"uuid","repository link","title","author","contributor","publication year","abstract","subject topic","language","publication type","publisher","isbn","issn","patent","patent status","bibliographic note","access restriction","embargo date","faculty","department","research group","programme","project","coordinates"
"uuid:f4b2e90c-373f-4106-ba6f-f832559eca85","http://resolver.tudelft.nl/uuid:f4b2e90c-373f-4106-ba6f-f832559eca85","Deep learning-based Image similarity estimation for geo-localization of Historical Aerial imagery","Liu, Yushan (TU Delft Civil Engineering & Geosciences)","Lindenbergh, R.C. (mentor); Dahle, F. (mentor); Wouters, B. (graduation committee); Delft University of Technology (degree granting institution)","2024","Historical aerial imagery serves as a valuable data source for observing Antarctica, facilitating an extended temporal scale of observation and enabling comparisons to deepen understanding of glacier dynamics. However, many historical aerial datasets, including the Antarctica Single Frames dataset utilized in this study, lack geo-referencing and orientation metadata essential for spatial analysis. One method of geo-referencing these historical images involves image matching to establish Ground Control Points (GCPs). This study focuses on the prerequisite for image matching: ensuring alignment between unreferenced historical images and already geo-referenced images in terms of scene and approximate resolution, a process termed 'geo-localization' herein.
Geo-localization is achieved by comparing the historical image with positions within a predefined geo-referenced Area of Interest (AoI). Two predefined remote sensing datasets are used: Sentinel-2 and Quantarctica Rock Outcrop Mask, from which AoIs are generated. Positions within the AoI exhibiting the highest similarity to the historical image are likely to correspond to the same ground area, thus providing the location of the historical imagery.
This similarity assessment employs two Siamese Networks: SigNet and ResNet-50. SigNet, originally designed for signature verification tasks, consists of four convolutional layers. In contrast, ResNet-50, initially developed for image classification purposes, is characterized by its deep architecture comprising approximately 50 convolutional layers, as suggested by its name. In this study, these two models are initially pre-trained on cross-domain datasets and subsequently adaptively trained with task-specific datasets created in this study. The adaptive training datasets comprise triplets of similar and dissimilar images pre-processed using methods devised in this study. An evaluation methodology based on confidence level is developed to assess the model and workflow performance, which is then applied to 51 test historical image samples.
Overall, the results indicate that the ResNet-50 based network outperforms SigNet, achieving a 95.5% average confidence level. However, the method does not meet the initial expectation of directly providing the location of the historical image within the AoI. Instead, it identifies potential locations. Nevertheless, this outcome is valuable as it streamlines the search process for subsequent image matching steps. For instance, a 95.5% average confidence level for the ResNet-50 based network correlates with an approximate 95.5% reduction in processing time for geo-referencing when integrated with image matching in subsequent steps.","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:1fad76b4-bcd3-4915-9a94-40e4ced35abd","http://resolver.tudelft.nl/uuid:1fad76b4-bcd3-4915-9a94-40e4ced35abd","The Effect of a Confining Cover Layer on Backward Erosion Piping Process: Investigation of the initial heave progression","Willemstein, Lotte (TU Delft Civil Engineering & Geosciences)","Hicks, M.A. (mentor); Brinkgreve, R.B.J. (graduation committee); Kok, M. (graduation committee); Wiggers, Albert (graduation committee); Sanders, Monique (graduation committee); Delft University of Technology (degree granting institution)","2023","The Netherlands is prone to flooding as more than a quarter of the country lies under sea level. To combat flooding and ensure that the country remains dry structures such are levees and dikes have been installed. However, older water retaining structures are more than ever failing the stringent safety standard assessments. These older conventional reinforcement measures, including berm constructions, are not only costly but require an expanse of ground to ensure performability.
Backward erosion piping is an internal erosion mechanism during which shallow pipes are formed in the direction opposite to the flow underneath water-retain structures as a result of the gradual removal of low cohesive material by the action of water. This mechanism is an important failure mechanism in both levees and dams where a cohesive layer covers a sand layer. Although failure resulting from backward erosion piping is not common, several levee failures in the United States, China and the Netherlands have been attributed to this mechanism.
There are mitigation measures known to stop the backward erosion mechanism. One such measure is the placement of a seepage wall, to create a physical barrier directly in the flow path trying to reach the lowest region of the hydraulic head. A review of the literature showed that current design rules only consider groundwater flow calculations when determining the likelihood of hydraulic heave, one of the failure modes within the backward erosion process. Hydraulic heave in the backward erosion piping context is closely linked to the quicksand condition, essentially stating that once the effective stress is zero, the sand particles become suspended, liquifying a solid layer. The absence of an assessment of the effective stresses during the design process in conjunction with hydraulic heave has contributed to the main research question addressed by this thesis; How does a restricted exit for groundwater flow affect hydraulic heave compared to Terzaghi’s free exit situation?.
The proposed workflow involves an extensive literature review of current and near-future decarbonisation technologies to replace diesel equipment and to create a haulage network based on block model data using the software Xpac Quarry solutions and its Haulnet package. Diesel equipment is imported from the Quarry solutions database and used as a base case to compare BEV and trolley assist simulations. Hydrogen and HVO fuel consumption have been calculated manually to obtain NPVs and associated emissions. An investigation into required infrastructure and energy requirements has been done to accurately define costs and resulting total CO2eq emissions.
The results indicate that replacing diesel at Ipoh with any of the decarbonization methods will result in a negative NPV as the infrastructure requirements need extensive capital investment of which the payback period often exceeds the life of mine. The least expensive method to implement HVO fuels, followed by BEVs and green hydrogen. Furthermore, it has been found that using BEVs instead of diesel at Ipoh is more environmentally polluting because producing 1 kWh of electricity is more polluting than producing the same energy worth of diesel. Green hydrogen is the least polluting method with no greenhouse gas emissions associated with it, followed by alternative fuels. When investigating the technological feasibility of the three main decarbonization options, hydrogen is the furthest away of being technologically feasible as from now. No green hydrogen using water electrolysers has been produced at an industrial scale, and a lack of technical expertise and infrastructure is present regarding distribution, transportation, and storage. Currently, no hydrogen LHD equipment is commercially available currently, and the same applies to BEVs that could replace the current equipment used at Ipoh. To bridge this gap, alternative fuels are the best option, but the market is competitive, and supply is limited. This project has given a good overview of current possibilities and clearly shows today’s options for decarbonisation and where industries stand with respect to infrastructure and equipment.
found that OMP removal rates were reduced by fouling due to the competitive effect of PMS. Take Trimethoprim as an example, its kinetics constant decreased from 22.491 to 0.916 s−1. PMS dosage also played an important role in both fouling alleviation and OMP removal. The improved performances were observed with increasing PMS dosage.","ultrafiltration (UF); wastewater treatment; AOPs; peroxymonosulfate","en","master thesis","","","","","","","","2025-11-30","","","","Applied Earth Sciences","",""
"uuid:096c6fd4-730b-4387-8c01-01df2bc1c949","http://resolver.tudelft.nl/uuid:096c6fd4-730b-4387-8c01-01df2bc1c949","Reliability assessment of quay wall renewal method Koningsgracht","Yassien, Jonas (TU Delft Civil Engineering & Geosciences; TU Delft Geo-engineering)","Korff, M. (mentor); Schweckendiek, T. (graduation committee); Kool, J. (graduation committee); Delft University of Technology (degree granting institution)","2023","This study focuses on the assessment of the reliability of the geobag wall system within the context of the Koningsgracht renewal project. The objective is to identify and understand the most sensitive phase during the project’s execution by conducting a comprehensive probabilistic analysis.
The geobag wall, a temporarily constructed component of Koningsgracht, emerges as the focal point of sensitivity in this study. Unlike other project elements, such as historic structures and conventional engineering components, the geobag wall possesses unique characteristics, notably its composition of individual geobags and the use of jute geotextile, which could result into individual instability.
The research delves into the analysis of failure mechanisms and limit states for the geobag wall, considering both the monolithic structure and potential local failures within its segments. The failure modes found include horizontal sliding, overturning and the rupture of the geotextile. Various parameters are examined to calculate factors of safety. To account for uncertainties inherent in geological and structural parameters, probabilistic methods are employed. Monte Carlo simulation and the First-Order-Second-Moment (FOSM) method are utilized to model the behavior of the geobag wall under different scenarios, encompassing a wide range of parameter combinations.
Correlations between parameters are introduced to simulate spatial variability, ensuring that the values of geological and structural factors align reasonably with one another. This approach reflects the real-world complexities of geotechnical systems. The analysis reveals intriguing results, with factors such as friction angle playing a significant role in horizontal sliding and overturning, while textile rupture remains relatively independent of geological parameters and heavily reliant on tensile strength of the jute geotextile. Additionally, wall dimensions, particularly height and width, are found to
exert a substantial influence on various failure modes.
Ultimately, the probabilistic analysis yields insights into the reliability of the geobag wall system. The study indicates a 1.625 · 10−4 probability of failure for the geobag wall system considering a Factor of Safety (FOS) of 1.0, aligning with the overall reliability of the Koningsgracht renewal method.","Quay wall; Probabilisitic Analysis; Reliability analysis","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:9bd9b6d0-b774-4223-a86e-bf216363d4f7","http://resolver.tudelft.nl/uuid:9bd9b6d0-b774-4223-a86e-bf216363d4f7","CO2 EOR Performance Evaluation in Unconventional Reservoir using Huff’n’Puff Scheme","Alfaleh, S.F.S. (TU Delft Civil Engineering & Geosciences)","Zitha, P.L.J. (mentor); Voskov, D.V. (mentor); Pluymakers, Anne (mentor); Delft University of Technology (degree granting institution)","2023","The increasing global demand for energy has necessitated the exploration of untapped potential energy resources. Unconventional oil reservoirs present a significant opportunity for development through various enhanced oil recovery (EOR) methods. Among these methods, the huff’n’puff scheme using Carbon Dioxide (CO2) EOR has emerged as a potent technique, considering both productivity and its impact on global warming. Unlike water injection, CO2 EOR exhibits high injectivity potential in tight formations, making it a promising approach.
This thesis focuses on investigating the performance of CO2 EOR in unconventional oil reservoirs using the huff’n’puff scheme through a comprehensive reservoir simulation study based on an open-source geological model. The study evaluates the effects of key parameters on oil production, including injection rate, injection time, soaking time, diffusion coefficient, and well completion.
The simulation results demonstrate that CO2 EOR can effectively enhance oil recovery from unconven- tional oil reservoirs. Specifically, the study reveals that implementing CO2 EOR increases cumulative oil production by 27% after 20 years compared to natural depletion cases. Furthermore, when incorporating a two-year primary recovery period, cumulative oil production is further elevated to 45%. By implementing the findings from the sensitivity study, cumulative oil production can be increased up to 67% in the optimum case.
In terms of the influence of the tested parameters on oil production, the study identifies that higher injection rates and longer injection, soaking, and production times for each cycle improve oil recovery until reaching an optimum value. Additionally, extending injection period by 10 times in each cycle with the same CO2 injected volume improved cumulative oil production by 7% compared to fixed injection rate as a result of longer diffusion and dissolution time. Moreover, implementing bottom CO2 injection targeting bottom layers improves vertical sweep efficiency due to buoyancy forces. The study also highlights the importance of the diffusion coefficient, as higher values facilitate faster CO2 transport, resulting in higher oil recovery and reduced CO2 reproduction.
This thesis provides valuable insights into the design and implementation of CO2 EOR projects in tight oil reservoirs. It emphasizes the need for careful selection of optimal operating conditions based on specific reservoir properties and highlights the significance of the diffusion mechanism in CO2 EOR performance. The findings contribute to the development of more effective CO2 EOR strategies for unconventional oil reservoirs, addressing gaps in previous research. Moreover, the study’s outcomes have practical implications for improving the design and implementation of CO2 EOR projects in the field, ultimately leading to increased oil production.","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:3bdfae69-df5d-4870-86bf-005a9b7b52f1","http://resolver.tudelft.nl/uuid:3bdfae69-df5d-4870-86bf-005a9b7b52f1","Simulation and history-matching of polymer-assisted water alternating CO2 injection using MRST","MODI, ANIKET (TU Delft Civil Engineering & Geosciences)","Zitha, P.L.J. (mentor); Mirzaie Yegane, M. (mentor); Delft University of Technology (degree granting institution)","2023","CO2 flooding is a widely employed method for enhancing oil recovery. However, it faces challenges stemming from differences in viscosity and density between oil and CO2, leading to poor sweep efficiency. This can result in issues such as viscous fingering, channelling, and gravity segregation, causing premature breakthroughs and excessive gas production. To address these concerns, the Polymer Assisted Water Alternating Gas (PA-WAG) technique combines the advantageous attributes of CO2 flooding, such as solubility and displacement, with the effective mobility control provided by polymer flooding. This results in a chemically enhanced Water Alternating Gas (WAG) flooding approach. A study by van Wieren et al. (2022) delved into the effectiveness of PA-WAG in addressing CO2 flow challenges and improving sweep efficiency by conducting core-flood experiments. This work builds upon that study by employing numerical simulations to replicate the core-flood experiments. These simulations shed light on the fundamental physical mechanisms during the PA-WAG injection process while also facilitating the calibration of flow parameters for practical implementation on a larger scale. The primary goal of this study was to comprehensively model three distinct enhanced oil recovery (EOR) techniques: polymer injection, CO2 flooding, and PA-WAG, all applied specifically to the Bentheimer sandstone cores. The objective was to history-match CT (Computed Tomography) scan saturation data, observed pressure drops, and oil recovery. A 2-dimensional (2D) model was constructed for each experiment, with CT scan images used to allocate varying porosity and permeability values to individual grid blocks. This enabled monitoring saturation distributions from the initial primary drainage phase onward. In the history matching of the primary drainage phase, parameters for relative permeabilities were determined from the Brooks-Corey equation, leveraging CT scan saturation data. The scaling of relative permeabilities based on CT scan saturations effectively accounted for capillary end effects observed in the core-flood experiments. During the history-matching of the polymer injection process, it was demonstrated that polymer-specific parameters, as determined from experimental data, could effectively modify waterflood relative permeabilities, thereby reducing the mobility ratio and accurately capturing the advancement of the polymer front. The formation of emulsions towards the end of polymer injection led to a notable increase in pressure drop, necessitating the incorporation of a high Residual Resistance Factor (RRF) to accommodate permeability reduction. In the case of history-matching for the CO2 flood, the black oil model successfully replicated the process of immiscible gas injection. It aptly captured gravity segregation while utilising CT scan saturation scaled relative permeabilities to assess the impact on oil recovery. The study unveiled that the relative permeability of gas under immiscible conditions was relatively lower than in miscible and near-miscible conditions. Simulating the PA-WAG injection by combining polymer and CO2 models effectively reproduced the core-flood experiments. The study substantiated the role of gas trapping in reducing the relative permeability of gas as a function of injection time, consequently leading to heightened pressure drops during subsequent polymer slug injections. The study showcased the efficacy of integrating black oil models for polymer and CO2 injection to successfully simulate PA-WAG injection and achieve unity with core-flood experiments yielding valuable insights into the physical processes underlying the technique.","EOR; core flood history match; Modelling and simulation; MRST; PA-WAG; Polymer flooding; CO2","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","Feasibility study of enhanced oil recovery by Polymer Assisted Water-Alternating-Gas",""
"uuid:ea00740d-d94e-4a10-a930-de4cf1740aa3","http://resolver.tudelft.nl/uuid:ea00740d-d94e-4a10-a930-de4cf1740aa3","Data assimilation for geothermal doublets using production data and electromagnetic observations: Assimilation of production and EM data","Oudshoorn, Christiaan (TU Delft Civil Engineering & Geosciences)","Werthmüller, D. (mentor); Voskov, D.V. (graduation committee); Slob, E.C. (graduation committee); Schmelzbach, Cédric (graduation committee); Delft University of Technology (degree granting institution); ETH Zürich (degree granting institution); Rheinisch-Westfälische Technische Hochschule (degree granting institution)","2023","The data assimilation process for geothermal reservoirs often relies on well data which primarily offers insights into the immediate vicinity of the borehole. However, integrating geophysical methods can provide valuable information beyond well proximity, possibly enhancing reservoir predictions. Electromagnetic methods can be sensitive to the decreasing conductivity from heat extraction in geothermal reservoirs. A scheme to incorporate electromagnetic data into a data assimilation process for geothermal reservoirs is presented and implemented in this study. First, an ensemble of prior models representing the reservoir uncertainty is used to determine the moments of the resulting temperature field using a forward geothermal simulation. Source and receiver locations are determined by maximizing the distance of the path through the expected temperature changes while ensuring that the source and receiver are not excessively distant. Subsequently, a conductivity model is implemented using an empirical relationship. The expected electric field response can then be simulated using an electromagnetic forward model. To assimilate the data, the Ensemble Smoother with the Multiple Data Assimilation (ES-MDA) method is employed. The findings demonstrate that the incorporation of electromagnetic data provides more information regarding the temperature field, which when combined with the localized data from the production well improves the temperature forecast accuracy of both the production well and the entire reservoir model.","Electromagnetic; Geothermal; numerical; Reservoir Simulation; Data Assimilation","en","master thesis","","","","","","","","2024-02-11","","","","Applied Earth Sciences","",""
"uuid:c8179612-f281-4f4c-a45c-e1a9672bfd8b","http://resolver.tudelft.nl/uuid:c8179612-f281-4f4c-a45c-e1a9672bfd8b","Safety Assessment for the Implementation of Autonomous Haulage Systems in an Open-Pit Mine","Aguilar Rodriguez, Mario (TU Delft Civil Engineering & Geosciences)","Buxton, M.W.N. (mentor); Soleymani Shishvan, M. (mentor); Lottermoser, B. (graduation committee); Rinne, M. (graduation committee); Delft University of Technology (degree granting institution)","2023","The implementation of autonomous haulage systems in open-pit mines is a progressive step in the industry, but it brings potential safety risks that need careful evaluation. This study developed a discrete event simulation model to analyze and evaluate these risks in different operating scenarios -fully autonomous, hybrid (a mix of autonomous and human-operated vehicles), and non-autonomous operations.The simulation model was developed using the HAULSIM and Anylogic software, integrated mine layout, haulage operations, and various fleet compositions. It provided insights into collision risks, a significant concern in mining safety literature. Results showed that collisions were inversely proportional to the number of autonomous vehicles in operation, indicating the potential safety advantages of fully autonomous operations. However, certain high-traffic intersections were identified as high-risk areas, emphasizing the need for targeted risk mitigation strategies. Further, a profile risk matrix was developed to provide a comprehensive view of collision severity and likelihood in each scenario. This highlighted the impact of collisions on both human safety and project operations. Based on the results, risk mitigation strategies were proposed, with a focus on redesigning intersections, implementing strict rules for human-operated trucks in autonomous zones, and improving autonomous vehicle capabilities. The study, while insightful, was limited by assumptions and the generic nature of operational data used in the simulation. Therefore, future research should seek to incorporate more detailed, mine-specific data and empirical insights from projects that have implemented autonomous haulage systems. Continuous advancements in autonomous technology and simulation modeling will be key to ensuring a safe and productive mining environment.
We examined two diverse datasets, representing a carbonate platform (Costa Field) and clastic formations (Volve Field). The Costa dataset, including 17 wells across a single reservoir, and the Volve dataset, comprising three wells across three different reservoirs, allowed for evaluating the robustness of our approach under different geological conditions. A critical part of our methodology is feature engineering, particularly incorporating vertical variability. We integrated measurements from adjacent well log readings into our models, recognizing the importance of spatial context and the smoothing effect of well logs over small-scale heterogeneities. This improved prediction accuracy by accounting for shared geological history and depositional environments in proximity.
In Costa Field, blind tests showed R2 scores up to 0.64, and validation R2 scores reached up to 0.8 using a leave-one-well-out cross-validation method. For the Volve Field, blind test R2 scores were up to 0.84, 0.76, and 0.78 for Hugin, Sleipner, and Skagerrak formations, respectively. These results, while satisfactory, underscore the potential of machine learning methods in accurately predicting permeability and highlight the need for effective feature engineering.
This work advocates that while machine learning holds promise for automated feature engineering, human intervention, specifically to incorporate spatial context, can still significantly enhance predictions. Future advancements may seek to internalize this spatial awareness within the machine learning algorithms themselves","Machine Learning (ML); Permeability; Petrophysics","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:f1a41622-b59f-42a6-bc7a-f7371038278f","http://resolver.tudelft.nl/uuid:f1a41622-b59f-42a6-bc7a-f7371038278f","Peering into the Heart of Thunderstorm Clouds: Insights from Cloud Radar and Spectral Polarimetry","Mak, Ho Yi Lydia (TU Delft Civil Engineering & Geosciences)","Unal, C.M.H. (mentor); Schleiss, M.A. (graduation committee); Dias Neto, J. (graduation committee); Glassmeier, F. (graduation committee); Delft University of Technology (degree granting institution)","2023","Lightning is a natural phenomena that can be dangerous to humans. It is however challenging to study thunderstorm clouds using direct observations since it can be dangerous to fly into thunderstorm clouds. In this study, cloud radar with millimeter wavelength is used to study the properties and dynamics of thunderstorm clouds. It is based on a case of thunderstorm on 2021-06-18 from 16:10 to 17:45 UTC near Cabauw. Polarimetric radar variables are used to investigate possible hydrometeors in the clouds and look for vertical alignment of ice crystals that is expected due to electric torque. The technique of Doppler spectra analysis, which has not been used in previous studies about thunderstorms so far, is used to help understand the behaviours of different types of particles within a radar resolution volume. Due to challenges posed by Mie scattering, scattering simulations are carried out to aid the interpretation of spectral polarimetric variables. From the results, there is a high chance that supercooled liquid water and conical graupel are present in thunderstorm clouds. There is also a possibility of ice crystals arranged in chains at the cloud top. Ice crystals become vertically aligned a few seconds before lightning and return to their usual horizontal alignment afterwards. However, this phenomenon has been witnessed in only a few cases, specifically when the lightning strike is in close proximity to the radar's line of sight or when the lightning is exceptionally strong. Doppler analyses show that updrafts are found near the core of the thunderstorm cloud, while downdrafts are observed at the edges. Strong turbulence is also observed as reflected by the large Doppler spectrum width.","cloud radar; spectral polarimetry; thunderstorm; lightning","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:909190a5-b91d-4f67-8134-3f19756ed817","http://resolver.tudelft.nl/uuid:909190a5-b91d-4f67-8134-3f19756ed817","Assessing Land Ice Height Decrease of the Fleming Glacier using ICESat-2 Satellite Data: A 2019-2022 Analysis","Snellink, Kamil (TU Delft Civil Engineering & Geosciences)","Dahle, F. (mentor); Wouters, B. (mentor); de Roda Husman, S. (graduation committee); Delft University of Technology (degree granting institution)","2023","The following report investigates the land ice height decrease of the Fleming Glacier between 2019 and 2022 using ICESat-2 satellite data. This glacier is located on the Antarctic Peninsula, an area that has been severely impacted by global warming. Using data from the Advanced Topographic Laser Altimeter System (ATLAS) on board ICESat-2, more specifically its ATL06 product, the average land ice heights in 2019 and 2022 could be compared. This was done with the aid of Python and the icepyx library, which allows for an easy extraction of the desired data from the NASA Eathdata website. The raw data had to be processed and filtered to eliminate the NaN values and reduce the noise. The resulting height measurements were then plotted and an average rate of land ice height decrease of 4.40 metres over the 3-year period was found, which corresponds to a 1.47 m/year decrease. The findings of this study indicate a slightly lower value compared to the results reported by Friedl et al. in their 1994-2016 study. However, this discrepancy is plausible, particularly considering the episode of increased ice melting observed in the Fleming Glacier after 2008, which can be attributed to the disintegration of the Wordie Ice Shelf. Crucially though, due to an issue with the Reference Ground Track overlap the amount of common data points found was just 27. This is insufficient to draw definitive conclusions regarding the overall melting of the entire Fleming Glacier. Future research, especially involving the use of the ATL11 product, is therefore recommended for this region.","glacier; ICESat-2; Fleming Glacier; Remote Sensing; ATLAS; Antarctica","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","","69.416667, -66.666667"
"uuid:0f9531bc-7ce3-4c42-a40d-1a836c921b99","http://resolver.tudelft.nl/uuid:0f9531bc-7ce3-4c42-a40d-1a836c921b99","Impact of water quality on UV disinfection of indigenous spores in surface, flocculated, and softened water from a drinking water treatment plant","Straathof, Judith (TU Delft Civil Engineering & Geosciences)","Hull, Natalie (mentor); van der Hoek, J.P. (mentor); de Kreuk, M.K. (graduation committee); Delft University of Technology (degree granting institution)","2023","UV disinfection is an efficient way to inactivate chlorine resistant protozoan pathogens such as Cryptosporidium parvum and Giardia muris. In the United States, regulatory UV disinfection credit is typically granted when turbidity is <1 NTU. However, studies show turbidity does not correlate well with UV dose responses and partial inactivation when turbidity is > 1 NTU should be considered to avoid certain violations while still protecting public health. The objective of this study was to examine the impact of worst-case scenarios at drinking water treatment plants on UV disinfection. Indigenous spores from unfiltered source water and samples taken during the flocculation and softening steps at the Dublin Road Water Treatment Plant in Columbus, Ohio were exposed to Low-Pressure mercury UV254 disinfection from July 2019 to January 2020. Raw source water and softened water had similar dose responses despite significantly different water quality parameters. Flocculated water had the worst dose response: significantly lower maximum inactivation rate and higher residual population density than the other two water types despite having a lower turbidity than softened water. The modeled Geeraerd-tail maximum inactivation rates (k¬max) were 0.027, 0.021, and 0.030 cm²/mJ for raw source, flocculated, and softened water, respectively. The modeled Geeraerd-tail residual population density values (N¬res) were 1.168, 7.081, and 0.216 SFU/mL for raw source, flocculated, and softened water, respectively. Relationships between water quality parameters and modeled UV inactivation parameters were analyzed to determine and compare other potential indicators for UV disinfection to turbidity. Particle size and particle properties that govern the degree of particle-associated microorganisms best explained the differences in dose response between flocculated water and the other two water types. Larger particles are worse for UV disinfection. Microorganisms associated with particles are harder to disinfect with UV and lead to tailing. Climate change impacts on types, consistency, quantity, and quality of source waters for drinking water treatment make it especially important to understand UV disinfection kinetics under challenging scenarios. Informing regulatory changes to properly account for disinfection when turbidity is > 1 NTU could be especially useful for small or aged utilities that may not be as equipped to handle highly variable water qualities.","drinking water; UV disinfection; turbidity; particles","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:4f45c50d-ecf6-4888-b338-16337f96e9d6","http://resolver.tudelft.nl/uuid:4f45c50d-ecf6-4888-b338-16337f96e9d6","Modelling of cavern convergence and brine permeation after plug & abandonment of deep salt caverns","Maat, Sander (TU Delft Civil Engineering & Geosciences)","Buxton, M.W.N. (mentor); Ngan-Tillard, D.J.M. (graduation committee); Delft University of Technology (degree granting institution)","2023","Frisia Zout B.V. extracts salt from the subsurface by means of solution mining in the north-western part of The Netherlands. The caverns are situated in the Zechstein-II Halite at a depth of around 2.5 km. Because of this depth and the low operating pressure (around 60% of lithostatic pressure) the salt creep within the cavern is high. Once a cavern is at the end of its lifetime it is decommissioned and shut in. During the shut-in period the cavern blanket fluid is removed and replaced with brine and gets time to equalize in pressure and temperature with its surroundings before being permanently abandoned. At the time of abandonment there is still a small pressure deficit (cavern brine at 98% of lithostatic pressure at roof of cavern). At this pressure deficit there is, in theory, still some salt creep because of the difference in pressure between the cavern brine and surrounding salt walls induced by lithostatic pressure. Since the cavern is closed and still creeps, the brine will escape by means of permeation through the surrounding salt walls and roof. At this point an equilibrium is reached between the cavern convergence and the brine permeation around the cavern.
This research aims to get a better understanding of the cavern convergence and permeation processes after abandonment. For this, a cavern convergence- and brine permeation model is made. Next to this the potential surface subsidence due to the migration of brine to more permeable layers is investigated. In the convergence model, the cavern is modelled as a stack of cylinders and a Norton-Hoff power law squeeze model is applied to the cavern. The squeeze model consists of 2 parts, a linear and a nonlinear part. The nonlinear part is most significant during the production phase and in these high-pressure deficits the squeeze model is fitted on the available production data. Recent creep tests on salt samples under lower pressure deficits (Bérest et al., 2019) have confirmed that the linear part becomes the most significant in the low-pressure deficit region and have shown that the linear creep is smaller than the linear component of existing squeeze model used for production.
Next to this a sensitivity analysis was done on the convergence model by varying the input variables of the model. The parameters that have a large uncertainty and have a large impact on the model were the linear part of the squeeze model and the width of a slice. To give a range of outputs of the convergence model a P10, P50 and P90 scenario is created where these are percentiles from the input range of the sensitivity analysis. The outcome of the convergence model at a cavern size of 1Mm3 suggests a yearly cavern convergence of around of 5, 103 and 2313 m3/year for the P10, P50 and P90 cases respectively.
Since there is an equilibrium between the cavern convergence and the brine permeation, the output of the convergence model (convergence rate) can be used as an input for the permeation model (permeation rate). For the permeation model, different paraboloid shapes are fitted on each layer and are filled with brine from the converging cavern. Once all the salt layers are filled in, the brine reaches more permeable layers and can freely flow over a larger area. The permeation model is run with the P10, P50 and P90 convergence model scenarios as an input and predicts that the system fills after 26, 588 and 12,363 years respectively. At this point there could be some subsidence because the brine can freely flow over a larger area in the more permeable layers above the Zechstein. This subsidence is 0.016 mm/year for the P50 case after 588 years. A negligible amount compared to unrelated subsidence processes.
13
To conclude the cavern convergence rates (even the P10 at 5m3/year) are high compared to the permeability of salt according to the Darcy flow law (around 17 l/year). This could have multiple explanations. From the cavern perspective, the cavern convergence rates could be lower. This could be because of a threshold pressure for salt creep to occur (van Oosterhout et al., 2022) or because of some inaccuracies in the linear component of the squeeze model. Future research could focus on determining the creep rates of salt under low-pressure deficits. From the permeation perspective, other permeation paths next to permeability could be at play as well. In the cavern there could be permeation via anhydrite alterations or via micro fractures created during the production phase of the cavern. It would be good to look at these permeation processes in the future. Next to this the secondary porosity of the salt remains a question as well. A good understanding of this porosity is needed to assess the storage capacity of the overlying salt layers before the brine enters more permeable zones.","modelling; Salt cavern; Salt; Mining; Abandonment; Convergence; Permeation","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","European Mining, Minerals and Environmental Programme",""
"uuid:641e5df2-c411-450d-9095-342673a225a7","http://resolver.tudelft.nl/uuid:641e5df2-c411-450d-9095-342673a225a7","Petrophysical and Mechanical Characterization of the Volcanic Rocks in the Hellisheiði Geothermal Field and implications of Thermal Fracturing in CO2 mineralization","Redondo Garcia, Elara (TU Delft Civil Engineering & Geosciences)","Barnhoorn, A. (mentor); Delft University of Technology (degree granting institution)","2023","The level of advancement in the understanding of the mechanical properties of volcanic rocks is comparatively lower than that of sedimentary rocks. As part of the SUCCEED Project (Synergetic Utilisation of CO2 Storage Coupled with Geothermal Energy Deployment), which aims to investigate the feasibility of injecting captured and produced CO2 into the reservoirs to enhance geothermal production and achieve permanent CO2 storage at the Hellisheiði Geothermal Field in Iceland, this experimental research provides significant insights into the petrophysical and mechanical properties of the volcanic rocks collected from surface outcrops. The subsurface in Hellisheiði is mainly built up of hyaloclastite formations and interglacial basaltic lavas. During a field campaign samples were collected in different outcrops, ensuring that the samples were of high quality and sufficiently diverse to enable comprehensive analysis. Four samples per block and rock type have been prepared from the collected blocks, and they have been subjected to different laboratory tests to evaluate their petrophysical properties, such as porosity, density, and permeability, and their geomechanical behavior, using Unconfined Compression Test (UCS), Active-Source Acoustic Test, and Splitting Tensile Strength Test. Additionally, laboratory experiments have been conducted to investigate the impact of rapid cooling on rock damage due to thermal fracturing. The results show that there are interdependent relationships between porosity, bulk density, ultimate strength, Young's modulus, and wave velocities that can be observed when considering average values per rock. The rocks studied showed a negative correlation between porosity and other parameters and a direct correlation between ultimate strength and Young's Modulus. When examining individual rock samples, no significant correlations were observed between porosity and other parameters, however, those correlations where evident when comparing between different rock types, emphasizing the importance of analyzing rock properties from a broader perspective. The rocks studied could be classified into five units based on their petrophysical and mechanical properties. Ordered from higher porosity and lower mechanical parameters, these units are: unit 1 consists of hyaloclastite HH-1, unit 2 includes porous basalts HBA-18 and HPB-23, unit 3 consists of low-porosity basalts HB-4 and HBimp-9, unit 4 is made up of dike ND-6, and unit 5 comprises gabbro G. This implies that there is a notable variation in the properties of rocks between different units, but the properties of rocks within the same unit do not differ significantly. Volcanic rocks have a significant amount of unconnected porosity, which, if connected, can enhance the storage capacity of the reservoir and improve the reactive surface area of the rocks in contact with the reinjected fluid, leading to a more efficient mineral storage process. The results of a thermal shock conducted to simulate reservoir and injection temperatures (270ºC and 60ºC) have shown no significant changes in the petrophysical and mechanical properties of the rocks, indicating that this temperature difference does not increase the effective porosity nor compromise the integrity of the reservoir. This study validates the potential use of certain rocks collected from surface outcrops in Hellisheiði as reservoir analogs for future geological models, particularly those with lower porosity.","Rock mechanics; Volcanic rocks; CO2 storage; geothermal energy; CCUS","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","SUCCEED Project",""
"uuid:4343c799-d1c7-4cbc-8c11-79d6b4623a25","http://resolver.tudelft.nl/uuid:4343c799-d1c7-4cbc-8c11-79d6b4623a25","Countergradient momentum flux in the presence of rolls in the atmospheric boundary layer","Mak, Ho Yi Lydia (TU Delft Civil Engineering & Geosciences)","de Roode, S.R. (mentor); Jansson, F.R. (mentor); Nuijens, Louise (graduation committee); Delft University of Technology (degree granting institution)","2023","In the atmospheric boundary layer, when surface heat flux is small and mean wind shear is strong, horizontal convective rolls that are elongated along the wind shear are formed. This study attempts to explain the asymmetry of rolls in terms of turbulence using large-eddy simulations. A pressure gradient in the north-south y direction is applied, which results in an east-west geostrophic wind. It is shown that the turbulent kinetic energy components in the x and y directions are not equal when rolls develop. In addition, a countergradient regime is present for vertical momentum flux in the y direction in convective boundary layer with rolls. In the countergradient regime, the wind variance in the y direction is destroyed, contrary to being produced in the x direction. The presence of a countergradient regime for v'w' but not u'w' suggests that the eddy viscosity in the x and y directions would be rather different, and even become negative for v'w'. Thus, the existing parameterization scheme in global atmospheric models may need to be modified. However, the design of an improved parameterization scheme is non-trivial as the countergradient regime is non-stationary when stability decreases, while it does not exist in neutral or stable boundary layers with rolls.","large-eddy simulation; countergradient momentum flux; horizontal convective rolls; turbulent kinetic energy; eddy viscosity","en","student report","","","","","","Programme: Applied Earth Sciences and Geoscience and Remote Sensing","","","","","","Applied Earth Sciences","",""
"uuid:39eb1e64-e489-4948-a4b3-da91097abf15","http://resolver.tudelft.nl/uuid:39eb1e64-e489-4948-a4b3-da91097abf15","A case study of Pb-scaling in a geothermal project in the West Netherlands Basin","Essaf, Najoua (TU Delft Civil Engineering & Geosciences)","Wolf, K.H.A.A. (mentor); Hussain, A.A.A. (mentor); Claringbould, Han (graduation committee); Delft University of Technology (degree granting institution)","2023","This research was done in the framework of the RVO project on Development of a well impairment model for predicting geothermal clogging (DIMOPREC) .
The importance of developing new energy sources with lower carbon emissions than conventional hydrocarbon based energy sources has been globally recognized (Andrews-Speed, 2016). Geothermal energy is a lower carbon energy source, which can be used for both electricity production and for direct heat use (Fridleifsson, 2001).
However, radioactive mineral scaling can accumulate in filters and tubing of the geothermal facilities, which can be an operational hurdle as this scale needs to be removed with necessary caution. The problem is not only the riskiness of being exposed to radioactive elements, but also the rise in pressure caused by scale accumulation. This occurs at the filters resulting in more process stops. Another problem with the scaling is that it causes increasing injection pressure. Since there is a regulatory limit to this pressure, an increase in injectivity is not preferable. Here, a case of a low-enthalpy geothermal project is discussed where very limited radioactive galena, PbS, is found.
This geothermal system is modelled in the geochemical software package PHREEQC. The PHREEQC model shows that a fraction (78 wt.%) of the collected galena is produced in solid phase from the reservoir, and a smaller fraction (22 wt.%) is formed after the heat exchanger. Gamma ray logs analyses and sedimentation history are presented to find potential sources of Pb and S ions. With the geological history and literature study it is found that the radioactive Pb could be originated from the Zechstein and Rotliegend where it attaches strong to the Copper shale formations. Scale and water analysis show that most of the captured galena is transported in a solid phase into the geothermal facility.
In the second part we discuss the development of a SKID for scaling determination during geothermal production. It is proposed to design a new SKID with additional measurement and monitoring options, which is able to provide the requested input parameters for the PFREEQC model. Requested data acquisition for long term monitoring includes fluid pressure, flowrate, temperature and pH values. The mobile function makes it possible to sample at several surface locations along the line of the geothermal facility. The obtained and stored data can be analyzed and compared to other locations in order to find out whether or not the brine and its composition change, and if so, how it changes
In order to reduce the amount of radioactive PbS in the filters of the geothermal system, it could be considered to acidify the brine to a level where the minerals are dissolved. In addition, increasing the facility pressure and/or increasing the minimum brine temperature after the heat exchanger, could reduce the amount of galena precipitation captured in the filters of the geothermal facility.","Geothermal; Radioactivity; PHREEQC","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:4422e6b4-069a-452d-9c42-c2bd20d85d01","http://resolver.tudelft.nl/uuid:4422e6b4-069a-452d-9c42-c2bd20d85d01","Airborne LiDAR data tree cover map: LiDAR data as additional data to Sentinel-2 spectral images to enhance land cover classification","de Boer, Adam (TU Delft Civil Engineering & Geosciences)","Dahle, F. (mentor); Lindenbergh, R.C. (mentor); Delft University of Technology (degree granting institution)","2023","The following report will enlighten to which extent LiDAR data could enhance land cover classification. It focuses on the area Lemps (26510) in Southwest France where a land cover classification was made using Sentinel-2 spectral images during the fieldwork. Using the additional LiDAR data, the focus shifts to distinguish coniferous and deciduous trees. Training data from the LiDAR data has been selected in CloudCompare. Using the training data, features for coniferous and deciduous trees were extracted in python. The unique features were used as classifiers. Features based on the Intensity were found to be important. Based on the classifiers, two methods were used to classify the area. Random Forest and Nearest Neighbour were the classification methods. The classification using Random Forest was found to be more accurate. The Random Forest classification map has been compared with previously acquired Sentinel-2 classification maps. The Corine Land Cover Classification and the classification map from the fieldwork were compared to the classification of coniferous and deciduous trees using LiDAR. Lots of overlap was found with the Corine Land Cover, some overlap was present with the map acquired during the fieldwork. The map created during the fieldwork contained less training data, hence the model was not trained enough. If more training data is collected for both LiDAR and Sentinel- 2 classifications, LiDAR data could enhance the general land cover classification. Especially taking the intensity into account as a classifier.","LiDAR; Classification; Random Forest; Nearest Neighbour; Intensity","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","Bachelor End Project","44.351, 5.418"
"uuid:3c3c98c2-f253-4672-8952-f5ef08a2495e","http://resolver.tudelft.nl/uuid:3c3c98c2-f253-4672-8952-f5ef08a2495e","Remote prediction of soil types: A working methodology to predict Unified Soil Classification System (USCS) classes based on total geological history","Thapa, Shlagha (TU Delft Civil Engineering & Geosciences)","Ngan-Tillard, D.J.M. (mentor); Slob, Siefko (mentor); Rongier, G. (mentor); de Jong, Steven (mentor); Delft University of Technology (degree granting institution)","2023","The Dutch Ministry of Defence is interested in developing a tool or workflow that can be used to remotely predict Unified Soil Classification System (USCS) classes of any area to aid mobility-related decisions. Therefore, this study was initiated by Cohere Consultants in collaboration with NEO, a Dutch remote sensing company and Utrecht University to create such tool or workflow. This MSc thesis provides a study in how the total geological history (TGH) approach as proposed by \cite{TGHA} can be used for predicting soil USCS classes. This is done by implementing the core concept of the TGH into a decision tree model that makes use of many modules, sub-modules and supporting modules to characterise the tectonic, geologic and geomorphological setting of a soil unit. The modules are divided depending if the unit dealt with is a soil, rock or part of a mountain, whereby the soil module incorporates 7 sub-modules that characterize alluvial, lacustrine, coastal, marsh, aeolian, evaporitic and glacial/periglacial environments. The rock and mountain modules, on the other hand, attempt to determine the presence and characteristics of residual soils using a weathering grade system and a table with the weathering products of 23 common rock types. The performance of the decision tree model was tested using two pilot studies in Konna, Mali and Zamora, Spain and one validation study in 's Hertogenbosch. For each study, a map with the predicted USCS soil classes was generated for the study area. The pilot studies explored the possibility of combining the predicted USCS soil maps with topographic wetness index (TWI) and slope angle maps to make a qualitative prediction on the trafficability of the area. The pilot studies showed that the TGH-based decision tree model has potential for being expanded into a tool for aiding military mobility predictions. Next, the validation study compared the predicted USCS map for 's Hertogenbosch to 5 ground truth data points collected by the Dutch Ministry of Defence. The validation study concluded that the decision tree was in general able to distinguish between coarse grained soils and fine grained soils, however struggled with correctly predicting if a soil has high or low plasticity. Finally, the Mali pilot study was able to compare USCS soil predictions made using the decision tree model to those made by a classification of hyperspectral data (made by \cite{flipsen_2022}). Based on the comparison, there seems to be promise for future works to integrate the two methods to benefit from the detail achievable by the hyperspectral method and the qualitative soil descriptions using the TGH-based decision tree. Future recommendations include fine-tuning the decision tree model so that is is able to incorporate more detailed geologic or soil maps (currently has been trained with maps of about 1:500,000), incorporating remote sensing data to create soil units, quantifying uncertainty and possibly automatising the workflow.","TGHA; USCS soil classes; Decision Tree Model; Geo-Engineering; Total Geological History; Soil classification; Remote predictions; Remote sensing; Geologic maps; Mapping; Knowledge Based Engineering","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:9cf8a17f-716c-4142-a067-0b6df3a66f7c","http://resolver.tudelft.nl/uuid:9cf8a17f-716c-4142-a067-0b6df3a66f7c","Fault Damage Zone Fracture Network Connectivity: A graph theory approach towards the assessment of fault damage zone leakage risk using DFN and outcrop studies","Spaa, Hidde (TU Delft Civil Engineering & Geosciences)","Bertotti, G. (mentor); Delft University of Technology (degree granting institution)","2022","Capturing CO2 directly at industrial complexes and safely storing it in the subsurface is one of the proposed mitigation measures of climate change. One of these challenges is identifying suitable reservoirs that ensure the safe and permanent storage of CO2. Therefore, detailed integrity assessments should be performed on the caprock to accurately determine and manage the risks involved in the permanent storage of CO2 (Kaldi et al., 2013). This should include leakage risk quantification of (sub-seismic) fault zones in the primary seal (Zappone et al., 2021). This thesis aims to understand and predict the probability of caprock leakage through a fault-related fracture network. It specifically focuses on the network organisation of fault damage zone (FDZ) fracture networks and the impact of their topology on the connectivity of the fracture network. Topology, in the form of fracture node classification, has been used to determine the connectivity of fracture networks (Sævik and Nixon, 2017). However, this research points out that the connectivity of a fracture network cannot be solely determined by a linear relationship between the fracture node ratio and the connectivity. This methodology does not effectively succeed in capturing connectivity differences of different fracture networks. To research these differences, a measure of connectivity is introduced based on the graph theory concept of the giant component. In this concept, networks are connected by a certain amount depending on their node type. By using the total length of the giant component we find the largest component ratio (LCR). This measure of connectivity and its relationship with percolation was tested using a DFN simulator. The concept of the giant component allows us to study the connectivity of various fracture networks. This is done by developing an algorithm that is based on the concept of robustness that removes fracture segments from a fracture network, which in turn enables us to find a relationship between the topology and the connectivity of the network and assess its uncertainty. From the DFN simulations and the robustness algorithm, it is found that the relationship between connectivity and topology is unique for different fracture networks. However, it was concluded that in general a fracture network significantly starts to increase in its connectivity when the average node has 1.6 edges connected to it (k). It also showed that the highest uncertainity of fracture network connectivity is present at 1.9<k<2.2.
sands, namely a stone column vibroreplacement technique.","MID; Compaction; Gas behaviour","en","master thesis","","","","","","","","2023-10-11","","","","Applied Earth Sciences","",""
"uuid:d49c775f-63d5-4108-b8fb-fd1930cd59b1","http://resolver.tudelft.nl/uuid:d49c775f-63d5-4108-b8fb-fd1930cd59b1","Fouling and chemical stability study on SiC-Al2O3 ultrafiltration membrane for sodium alginate filtration under constant flux crossflow mode","Zhang, Luqianxue (TU Delft Civil Engineering & Geosciences)","Heijman, Sebastiaan (mentor); Jan, A. (mentor); Rietveld, L.C. (graduation committee); van Lier, J.B. (graduation committee); Delft University of Technology (degree granting institution)","2022","Trials of surface modifications using low pressure chemical vapor deposition (LPCVD) has successfully decreased the high temperature needed for the fabrication of SiC membrane from 2000°C to below 900 °C. With this great success on the reduction of the energy con-sumption, however, further studies on the chemical stability and the fouling features of this kind of membrane were necessary. In this research, experiments were done on the SiC-Al2O3 UF membrane fabricated by LPCVD to study its chemical stability in a NaClO solution and its fouling features when filtrating sodium alginate and surface water under constant flux cross-flow mode. The backwash efficiency and the fouling resistance were analysed as well to further elucidate the fouling composition.
According to the results, the SiC-Al2O3 membrane coated under higher temperature (860°C) remained stable in the NaClO solution for 200 h, (1% for 100 h and then 5% for 100 h) while the membrane coated under lower temperature (750°C) showed a water permeability increase during chlorine treatment, indicating the dissolution of the SiC layer. The high temperature coated membrane (860°C) had a better antifouling ability than low temperature coated mem-brane (750°C) and the pristine membrane especially when filtrating the pure sodium alginate (SA) solution without Ca2+ under normal flux (170 LMH) or the surface water under lower flux (65 LMH). Cake filtration was observed in the fouling curves when the critical flux was not exceeded. The addition of Ca2+ into the pure SA solution resulted in the decrease of elec-trical repulsion and the increase of bridging between foulants and membrane surface. These led to the severe fouling of the high temperature coated membrane. The low temperature coated membrane had better antifouling ability than high temperature coated membrane and the pristine membrane when 2 mmol/L of Ca2+ was added. However, the backwash (back-wash flux of around 340 LMH for normal flux condition and around 195 LMH for lower flux condition) was not efficient for all the membranes and should be improved in the future ex-periments.
have shown that the addition of the ATBS-modified HPAM polymer to the water in the WAG method increased the recovery by 10% over the normal WAG injection, by improving the mobility ratio and displacement efficiency. By implementing the PA-WAG on a carbonate rock saturated with crude oil, a base line experiment with regarding reservoir simulated recovery was established, with a recovery of 76%. The stability test under the presence of CO2 showed that the dissolved CO2 impacts the polymer viscosity. After the initial decrease in apparent viscosity to 54% of the original viscosity, the ATBSmodified HPAM polymer was able to recover its viscosity to 84% of its original apparent viscosity after 29 days of aging. These results were achieved under full saturation of the polymer solution with CO2 . In addition, the impact of CO2 at PA-WAG flooding CO2 concentrations was evaluated, which showed now degradation with the exposure to CO2. The study concludes that the ATBS-modified HPAM polymer performs excellently in the PA-WAG method for enhanced recovery, significantly outperforming the WAG injection method.
FEM simulations with continuum elements are typically not suitable for modelling discontinuities with no width, due to the inability to model discontinuous fields. One solution is to represent discontinuities using zero-thickness interface elements. Inserting zero-thickness interface elements allows for discretely modelling discontinuous behaviour between neighbouring continuum elements. The continuum elements are then used to represent the bulk behaviour and the zero-thickness interface elements discretely model the discontinuity.
A new constitutive law for zero-thickness interface elements that expands the cohesive zone model with friction is formulated in this thesis. The tangential stress response of the interface elements consists of a cohesive and frictional contribution. The cohesive component of the constitutive law is based on the Crisfield’s cohesive elasto-damage model, which is characterised by a linear elastic response to increased relative displacement, followed by degradation of the cohesive strength and stiffness. The elasto-plastic frictional component is based on the Dahl friction model and implemented in parallel to the cohesive component.
The implemented new constitutive law is verified in a large variety of loading conditions, including tangential loading, tangential loading with a reversion of loading direction and combinations of mixed-mode loading. The constitutive laws are validated based on shear box experiments performed on London clay where interface elements are used to model a predefined shearing plane.
The cohesive and frictional constitutive law can represent confinement-dependent tangential stress and residual stress at large relative displacements. These features, observed in the shear box experiments, could not be reproduced by the purely cohesive constitutive law. This new constitutive law can be used to better model discontinuities in geomaterials represented by zero-thickness interface elements.","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:d6319d52-4d53-4f8e-a443-7f3aa288a138","http://resolver.tudelft.nl/uuid:d6319d52-4d53-4f8e-a443-7f3aa288a138","Soil-grout interface friction for HDD installed heat transport pipes","Pleij, Lodewijk (TU Delft Civil Engineering and Geosciences)","Broere, W. (mentor); Šavija, B. (graduation committee); Dieudonné, A.A.M. (graduation committee); Delft University of Technology (degree granting institution)","2022","The soil-grout interface friction was measured to be in between 0.0 [kPa] and 14 [kPa]. To measure this friction, a special research method was invented that enabled a tunnel to be recreated. With this setup, any formation could be used. The formation could be created with a hole in the middle which simulated a borehole. Next, by filling and pressurising this hole with a bentonite-water suspension, a stable borehole could be simulated. This borehole was then filled with drillgrout to recreate a tunnel filled with grout. This grout column could then be pulled out of the soil formation so that the friction between the drillgrout and soil could be measured. In this setup, no normal forces were present. Due to the absence of normal forces no friction angle could be deducted which made it impossible to estimate the effect of the friction at the depth where a pipe laid by HDD would generally be found. It was concluded that based on the data found, it is not recommended to use grout as a borehole filling around heat transportation pipes. Although the friction would be mainly determined by the filter cake strength, which is comparable to a weak clay, effects like irregular borehole diameters and large soil stresses at the depth of the pipe, would create a frictional force that is large enough to cause buckling or failure of the insulating PUR layer.","HDD; Friction; Soil; Drillgrout; Drilling; Pipe; Bentonite; DPIA","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:06c78212-894c-4779-a018-0df7fe7e9225","http://resolver.tudelft.nl/uuid:06c78212-894c-4779-a018-0df7fe7e9225","Coupling ORCHESTRA to Python: A modelling framework for simulating waste degradation in a bioreactor","de Zeeuw, Guido (TU Delft Civil Engineering and Geosciences)","Heimovaara, T.J. (mentor); Andrade Corona, C.F. (graduation committee); Meeussen, J.C.L. (graduation committee); Voskov, D.V. (graduation committee); Delft University of Technology (degree granting institution)","2022","Over the years, modelling frameworks have been proposed to describe and predict the degradation of municipal solid waste in landfills. These frameworks, however, fail to couple the kinetic solutions to the real-time equilibrium state of the system. Because of this, fundamental processes such as pH changes, NH4+ adsorption to the waste surface and changes to the fluid composition are often not (or inadequate) taken into account. In this study, we propose a degradation model that couples a kinetic solver to the chemical equilibrium software, ORCHESTRA. For this, a tool is developed that allows seamless operability between ORCHESTRA and the Python environment. The modelling framework is used to simulate the degradation of solid organic matter in a batch reactor following a simplified, but comprehensive, reaction network. Reaction rates are based on Monod kinetics that includes a wide variety of inhibition functions. The Freundlich equation is used to capture NH4+ adsorption to the waste surface. Results from various case studies show that the modelling framework is suitable for coupling real-time landfill chemistry to degradation kinetics. We found that NH4+ concentrations play a dominant role in the presented model. While low NH4+ concentrations limit biomass growth by substrate inhibition, high concentrations (>0.002 4
mol/L) affect the hydrolysis rate by toxicity inhibition. This translates to a model that is sensitive to a variety of input parameters such as the initial C/N ratio, the Kd (degree of adsorption) value and the initial organic fraction. A comparison with literature studies, however, implies that the model lacks fundamental processes such as gas and fluid transport or changes in volume and temperature. In addition to this, we discuss that the Freundlich isotherms may be inappropriate to capture adsorption in a coupled framework as no ion exchange is taken into account. Models that do so, such as the NICA-Donnan model, could improve the model results significantly.","Municipal Solid Waste treatment; Biogeochemical model; ORCHESTRA; ammonium adsorption","en","master thesis","","","","","","https://gitlab.tudelft.nl/guidozeeuw/orchestra_python","","","","","","Applied Earth Sciences","CURE",""
"uuid:6c44a1bf-9550-4a00-bfa8-175ffc177e33","http://resolver.tudelft.nl/uuid:6c44a1bf-9550-4a00-bfa8-175ffc177e33","Deformation of sandstones under cyclic loading relevant for underground energy storage","HERNANDEZ ACEVEDO, EDGAR (TU Delft Civil Engineering & Geosciences)","Hajibeygi, H. (mentor); Barnhoorn, A. (mentor); Naderloo, M. (graduation committee); Ramesh Kumar, K. (graduation committee); Delft University of Technology (degree granting institution)","2022","Underground energy storage (UES) in porous and cavity reservoirs can be used to balance the mismatch between the production and demand of renewable energy, as well as for securing gas and oil supply during shortage or high demand periods. Understanding the geomechanical behavior of these reservoirs under different storage conditions, i.e., storage frequency and fluid pressure, is key in defining their capacity and effective lifetime. This thesis work presents a rigorous analysis performed on sandstones to unravel their geomechanical response under cyclic loading. This study includes, importantly, both experimental and numerical investigations under several conditions which are relevant to UES. The rock response was studied considering cyclic stress states above and below the onset of dilatant cracking, under different frequencies and amplitudes. Within the number of cycles studied, measurements of axial strains and acoustic emissions indicated that inelastic strains accumulated cycle after cycle following an exponentially decreasing rate. Five types of deformations were interpreted: elastic, plastic, viscoelastic, cyclic-plastic and brittle creep. Based on these novel experimental results and observations, Nishihara's constitutive model was used for simulating viscoelastic and brittle creep deformations, while dilatant plastic strains were modeled using a Hardening-Softening model. Finally, an extension of the Modified Cam-Clay model was proposed to account for cyclic-plastic compaction. This approach can be extended and improved to study cyclic sandstone deformation's implications on subsidence, fault reactivation and cap rock flexure, among other physical phenomena impacting a reservoir's storage capacity.","Cyclic loading; Underground energy storage; Sandstone","en","master thesis","","","","","","","","2023-12-31","","","","Applied Earth Sciences","",""
"uuid:28bf13e1-a567-4d9d-98f4-a864e2c7eb15","http://resolver.tudelft.nl/uuid:28bf13e1-a567-4d9d-98f4-a864e2c7eb15","Simulation of CO2 Storage in Complex Geological Formations Using Parameterized Physics Spaces","ZHANG, ZILIANG (TU Delft Civil Engineering & Geosciences; TU Delft Geoscience and Engineering)","Hajibeygi, H. (mentor); Wang, Y. (graduation committee); Vuik, Cornelis (graduation committee); Boon, M.M. (graduation committee); Delft University of Technology (degree granting institution)","2022","In this work, an efficient compositional framework is developed to simulate CO2 storage in saline aquifers with complex geological geometries during a lifelong injection and migration process. The novelty of the development is that essential physics for CO2 trapping are considered by a parametrization method.
The numerical framework considers essential hydrodynamic physics, including hysteresis, dissolution and capillarity, by means of parameterized space to improve the computation efficiency. Those essential trapping physics are translated into parameterized spaces during an offline stage before simulation starts. Among them, the hysteresis behavior of constitutive relations is captured by the surfaces created from bounding and scanning curves, on which relative permeability and capillarity pressure are determined directly with a pair of saturation and turning point values.On the other hand, the new development allows for simulation of realistic reservoir models with complex geological features by implementing in corner point gird. The extension to corner point grid is validated by comparing simulation results obtained from the cartesian box and the converted corner-point grid of the same geometry, and it is applied to a field scale reservoir eventually.
A set of sensitivity analysis reveals the roles of various physical effects and their interactions in CO2 trapping in a realistic reservoir model, apart from the investigation on the impact of migration path, linear trapping coefficient and depth. The results show the proposed compositional framework casts a promising approach to predict the migration of CO2 plume, and to assess the amount of CO2 trapped by different trapping mechanisms in realistic field-scale reservoirs.","Geologic carbon storage; Compositional simulation; Multiphysics interaction","en","master thesis","","","","","","","","2023-08-24","","","","Applied Earth Sciences","",""
"uuid:49827786-deb7-4417-ba3d-67d1660471d8","http://resolver.tudelft.nl/uuid:49827786-deb7-4417-ba3d-67d1660471d8","Fracture characterisation in carbonate reservoirs for geothermal production","Barreiros Jorge, Sofia (TU Delft Civil Engineering and Geosciences)","Bruna, P.B.R. (mentor); Delft University of Technology (degree granting institution)","2022","Subsurface energy projects carry high risk due to the lack of data available to accurately model reservoir characteristics. There is a need for high level analysis to extrapolate subsurface data from a single point (i.e. a well). The focus of this study will be on fracture characterisation in a carbonate reservoir located within the Geneva Basin for the purposes of geothermal exploration. The goal is to use fracture characterisation techniques in the form of an OBI analysis and the use of a fracture growth model with a focus on geomechanics to predict the possible fracture growth patterns. This work will allow for a better understanding of fluid flow and permeability throughout the reservoir. As well as explore the benefits and limitations of this approach. The case study is a fractured carbonate reservoir made up of limestone and marlstone packages. To calculate the paleo stress environment, the fracture data is used to back calculate the possible magnitude of the stress field during fracture formation. This choice was made after careful consideration and comparison of the fracture data with the fault data. The output of this modelling will be a DFN with multiple layers controlled by the fracture density. This model can hopefully be used in the future for dynamic simulation to understand the impacts of these assumptions and validate with production data from the well.
Within this bachelor thesis, a beamforming technique is adopted to provide a framework that can be used to detect seismic events recorded by the passive seismic network. The goal is to separate coherent signals from noise and characterize the signal (e.g., estimate propagation direction). The objective of this bachelor thesis is to assess whether beamforming is capable of lowering the detection threshold, and determining the signal’s apparent velocity and back azimuth, using data recorded by the Kwintsheul seismic array. For applying the beam- forming technique, Kwintsheul data was implemented in a python code, originated from Remote Online Sessions for Emerging Seismologists (ROSES).
Following applying the beamforming technique, the results of the detection, and the parameter estimation of the back azimuth and apparent velocity, are given for the P-wave and S-wave, 300.96 deg. 6.43km/s and 315 deg. 3.31km/s, respectively. The results of the Fisher statistics and the f-k analysis show that beamforming is capable to discriminate coherent signals from noise.
For beamforming analysis, it is necessary to have array elements that are distant from the event. As the ar- ray design is fixed, it is, therefore, necessary to eliminate data from array elements in the proximity of the event. Hence only data from array elements in the far-field is used for beamforming. This approach decreases the num- ber of array elements, and therefore the signal to noise ratio is decreased as well. In this case, to improve the resolution of the applied beamforming technique, the array design needs to be modified, with all array elements situated in the far-field.","Signal analysis; beamforming; Earthquake analsyis; microseismicity; Geothermal","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:cd38305d-8758-4b27-b1f3-680955055370","http://resolver.tudelft.nl/uuid:cd38305d-8758-4b27-b1f3-680955055370","Assessment of the Conditions of Abandoned Wells in Potential CO2 Storage Reservoirs","Mozas Maradiaga, Javier (TU Delft Civil Engineering and Geosciences)","Hajibeygi, H. (mentor); Boon, M.M. (mentor); Delft University of Technology (degree granting institution)","2022","This project is part of the larger REX-CO2 project, which assesses the re-usability of abandoned wells in reservoirs targeted for CCS operations. It comes as a necessity to also assess the abandoned wells that will not be re-purposed, by assessing the risk they pose in terms of allowing the stored CO2 to resurface across them, which is the focus of this work.
In order to assess these wells, a decision making framework was developed that will consider the main mechanisms that can lead to leakage across an abandoned wellbore. The objective is that this framework could be used by an operator of a prospective reservoir for a CCS project, prior to the start of the operations, in order to understand the risk associated with the abandoned wells present, and take decisions for remediation if necessary and possible. This framework considers three main aspects relevant for the formation of leakage paths. These are the effectiveness of the abandonment process itself, the chemical processes that can lead to the degradation of the isolation elements, and the mechanical processes that can lead to loss of integrity.
The framework consists of two main parts. The first is a qualitative analysis, based on a thorough literature review, assessment of experts and testing with case studies. This qualitative assessment consist of decision trees, formed by a series of questions which answers will dictate the final outcome that will reflect the state of the abandonment. The second part is a quantitative risk analysis. For this purpose ""Bayesian Belief Networks"" are used which is a probabilistic tool used for calculating the relative probability of a combination of factors. The BBNs are constructed and populated based on a thorough literature review including data on experimental results. In addition, geomechanical simulations were carried to populate these models. All this data was processed and converted into normal random distribution functions, which were used to infer the probabilities that would be included in the BBNs. The final outcome of the BBNs reflect the probability for leakage to occur.
Both the qualitative and quantitative parts of the framework are integrated together in order to obtain a complete analysis. The complete framework was tested with case studies based on real wells for which the abandonment states are known and reported by the operator, to observe how the outcome of the framework analysis matched the outcomes of the analysis performed by the operator.
With this study, a complete and systematic framework was developed that can be used to aid decision making for prospective CCS projects in the future. The framework is constructed such that it has the capacity to be improved and expanded in the future, to increase its consistency and broaden its applications. A series of potential improvements are also explained at the end of this report. Furthermore, the framework can be used to challenge the current abandonment standards and assess what will have to be changed to adapt the current abandonment techniques so that they include CCS projects.
conducted using cyclic direct simple shear (DSS) and cyclic triaxial (CTX) tests as these tests under constant-volume conditions can evaluate the change in pore pressure within a soil accurately. Previous study shows what importance the relative density and sloping ground conditions, known as drained shear bias, have on the cyclic resistance to liquefaction of the tailings. However, in practice the pore water is not bounded within the material and excess pore water can flow out through installed drains. A round-robin program, issued by the University of Western Australia (UWA), requested a study on the liquefaction response of a particular fine-sand tailings material. Inspired by this round-robin program, an interest raised in studying the cyclic shear response of tailings by using a direct shear box to investigate the cyclic behaviour under partially drained conditions. With use of the direct-shear apparatus of Wille Geotechnik, a test program has
been set up to study the influences of relative density and drained shear bias under stress-controlled cyclic shearing and under constant normal load conditions.
Results of the experiments met the expectations that denser soils have a 9.6% higher cyclic resistance ratio (CRR), and samples with applied drained shear bias have a 32% lower CRR compared to samples tested with level ground conditions. Furthermore, samples which underwent post-cyclic shearing showed strain-hardening responses and yielded higher shear stresses compared to the monotonic test, indicating that the constant normal load further densified the samples during cyclic shearing. However, during the experiments, it was
quickly found out that the loading frequency was not being applied optimally making it not possible to analyse influence of partially drained conditions . This study showed promise on its capabilities to study cyclic shear loading on a soil. For future work, it is suggested to perform similar tests under a uniform loading frequency with the use of a shear box to evaluate its capabilities to study on partially drained conditions. It is also recommended to conduct tests under constant volume conditions, to evaluate the shear-box apparatus’ capabilities to
study the liquefaction response of a soil due to excess pore pressure generation.","Direct Shear Box; Cyclic loading; Tailings; CSR; CRR; Relative Density; void ratio; CDS; post-cyclic shear test","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:881307e6-9504-4616-a0b9-ed2425eebfe2","http://resolver.tudelft.nl/uuid:881307e6-9504-4616-a0b9-ed2425eebfe2","The influence of vertical loading on the lateral behaviour of rigid monopile foundation in clay soil: An analysis using 3D Finite Element Modeling","de Voogd, Rein (TU Delft Civil Engineering and Geosciences)","Gavin, Kenneth (graduation committee); Askarinejad, A. (graduation committee); Pisano, F. (graduation committee); Wang, H. (mentor); Zhang, Y. (mentor); Delft University of Technology (degree granting institution)","2022","Monopiles with large diameter (larger than 6 m) and low aspect ratio (less than 6) are increasingly used in offshore wind farms. These foundations demonstrate a rigid response under lateral loading. The validity of the existing design methods, that are based on small diameter flexible piles, has been questioned by both the industry and researchers. In addition, the monopiles are subjected to both lateral and vertical loads. The influence of vertical load on the lateral design of short rigid monopiles in clay soil is not clear. This study aims to perform a comprehensive study on the influence of vertical load on the lateral response of monopile foundations in clay soil.
All analysis in this study was performed using 3D finite element modeling in PLAXIS 3D software. The NGI-ADP constitutive model was adopted to simulate the nonlinear mechanical behaviour of clay. Considered in the analysis is a short rigid pile with a diameter of 10 m (L/D = 3) and a long flexible pile with a diameter of 2 m (L/D = 15). The analyzed clay soil profiles consist of a normally consolidated clay soil and an overconsolidated clay soil with a constant undrained shear strength profile equal to 30 kPa. For each pile in each type of clay soil, a pure lateral loading scenario is performed first to assess the validity of current design methods. Subsequently, a combined loading scenario is performed to assess the influence of vertical loading on the lateral behaviour of rigid monopile in clay soil.
Results of the pure lateral loading scenario suggest that current design methods heavily underestimate the lateral capacity of rigid monopile foundations in both clay soil profiles analyzed. According to the findings of this study, it can be concluded that current design methods are not fit to provide an accurate assessment regarding the lateral load response of rigid monopile in clay soil. In order to correctly assess the lateral load response of rigid monopile in clay soil, a method consisting of a 3D finite element model akin to the model used in the research or a PISA design model is advised. A potential third design method, the 1D rotational spring model, is also proposed.
Results of the combined loading scenario suggest that the presence of vertical loading causes a decrease in lateral and moment capacity of the rigid pile in both clay soil profiles analyzed. However, the influence is negligible when the vertical load magnitude is smaller than 50% of its bearing capacity. To quantify the influence of vertical load on a monopile foundation, a series of load analysis were performed on a real offshore wind turbine with a 5MW power capacity. It was found that the vertical load on a typical monopile foundation in clay is around 27% of its bearing capacity. According to the findings of this study, it can be concluded that the influence of vertical load on the lateral response of rigid monopiles in clay soil is limited and can be ignored in foundation design.
The results of the study indicate a lagoon depositional environment for the Early Permian, a carbonate self environment for the Middle-Upper Permian successions, with dimensions of 80 square kilometers and a general east-west orientation. The thickness of the carbonate deposits reaches a maximum of 2500 kilometers to the north of the reconstituted paleoshore. A Sabkha environment has been interpreted for the Upper Permian with significant deposits of anhydrite. Structurally, it was observed that the Permian is not affected by major normal faults.
Conversely, significant folds have been identified at the seismic data, with a general east-west strike and a northwards dip. Based on the displacement of seismic reflectors, two tectonic episodes have been identified. The first is dated to the Upper Carboniferous - Early Permian and the second to the Early-Middle Triassic. Decompaction calculations indicate low subsidence rates and general stability during the Early Permian. This was followed by significantly increased subsidence rates during the Middle and Upper Permian.","Permian; Tunisia; Jeffara Area; Carbonate Platform; Sbakha; Structural Reconstruction; Environmental Reconstruction","en","master thesis","","","","","","","","2023-03-19","","","","Applied Earth Sciences","",""
"uuid:77390c5e-f0a0-49fc-9819-82a5704f6e69","http://resolver.tudelft.nl/uuid:77390c5e-f0a0-49fc-9819-82a5704f6e69","Calibrated cryogenic amplifier measurements: Determining the characteristics of a current pumped nanobridge Josephson Parametric Amplifier using Short-Open-Load and Thermal Calibration","Locht, Lieuwe (TU Delft Applied Sciences)","Steele, G.A. (mentor); Blanter, Y.M. (graduation committee); van der Sar, T. (graduation committee); Bruno, A. (graduation committee); Franse, W.J.M. (graduation committee); Delft University of Technology (degree granting institution)","2021","In this project, we have done a calibrated measurement on a previously designed and fabricated current pumped Josephson Parametric amplifier. We have installed a microwave switch into our crygenic fridge tobe able to get a calibrated response measurement using Short-Open-Load calibration, which we used withmeasurements of the gain and flux tunability of the device. This showed that our previous measurements onthe gain deviated significantly, with about 10dB. We also did a thermal calibration on the amplifier by heatingthe plate it was attached to, and found that the input noise approximates the limit of a half quantum of noise.","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:66f4532c-df3e-40a7-a575-7c314c7a4385","http://resolver.tudelft.nl/uuid:66f4532c-df3e-40a7-a575-7c314c7a4385","Evaluating the value of Integrated Geodetic Reference Stations: Assessment of the InSAR and GNSS observations","ZOUROS, JOHN (TU Delft Civil Engineering and Geosciences)","Hanssen, R.F. (mentor); van Diepen, S.A.N. (graduation committee); Slobbe, D.C. (graduation committee); Delft University of Technology (degree granting institution)","2021","Interferometric Synthetic Aperture Radar (InSAR) and Global Navigation Satellite Systems (GNSS) are widely used to monitor the dynamic behavior of the Earth. InSAR is a geodetic technique that estimates millimeter-level relative displacement time-series in an opportunistic network of a multitude of coherent points on the Earth’s surface, in a local datum. GNSS uses ground-based instrumentation to acquire time-series data over a limited number of specific and well-defined points in a known geodetic datum.The Integrated Geodetic Reference Station (IGRS) is designed to combine these (and other) techniques into one common instrument, establishing an integrated benchmark, i.e., a GNSS antenna and two radar corner reflectors, ensuring an identical kinematic behavior. This enables a geodetic datum connection, effectively enabling the InSAR results to be represented in a common geodetic datum, instead of a free network.However, the efficacy of the IGRS has not yet been proven, i.e., a thorough analysis of the first empirical results of an IGRS network has not yet been performed.Here we show that by using three years of data from a spatio-temporal network of 29 IGRS stations in an area of 60×60 km, and 742 independent Synthetic Aperture Radar (SAR) acquisitions, we reach a high level of agreement, demonstrating that IGRS can be used to connect InSAR information products to a well-defined geodetic datum.By using an Overall Model Test with a significance level of 5% we found that 96% of the double-difference arcs in time and space, sustain the null hypothesis that both the InSAR and the GNSS results stem from the same distribution. We found that the main reason for rejecting the null hypothesis for the remaining 4% of the double-difference arcs is that the results of both the InSAR and the GNSS are affected by a leakage of signal from the functional to the stochastic model. For the InSAR observations there is inadequately modeled atmosphere leaking into the stochastic model, while for the GNSS it appears that the precision estimate of the periodically moving stations is worse than the non-periodically moving stations, which suggests that the stochastic model is influenced by the the functional model.In the end, this study proved the efficacy of the IGRS to connect different geodetic datums, and this enables the InSAR results to be integrated in a well-defined geodetic datum.","Integrated Geodetic Reference Stations; InSAR; GNSS","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:e3a039d4-e969-4cd2-822c-4135d09040ae","http://resolver.tudelft.nl/uuid:e3a039d4-e969-4cd2-822c-4135d09040ae","Earthquake Detection in Zeerijp: A Study on the Usage of Template Matching and Neural Networks for Detection of Small Earthquakes in Zeerijp","van Deventer, Julia (TU Delft Civil Engineering & Geosciences)","Vossepoel, F.C. (mentor); Ruigrok, Elmer (graduation committee); Drijkoningen, G.G. (graduation committee); Weemstra, C. (graduation committee); Diab Montero, H.A. (graduation committee); Delft University of Technology (degree granting institution)","2021","In this thesis, we discuss two pattern recognition techniques, template matching, and neural networks. We discuss how these techniques have been used for the development of two earthquake detection algorithms. The first algorithm is based on template matching and the second is based on deep learning. The algorithms are designed for the detection of small <0.5M events in the subsurface of Zeerijp, Groningen. These two algorithms have been compared to assess their earthquake detectability and practicality. The systems have been compared using field data from Zeerijp. The algorithm based on deep learning (a neural network) produced too many false positives considering the amount of seismic data we would like to use it for. The algorithm based on template matching did not produce any false positives during testing. The template matching system has been fed six months of continuous seismic data fromZeerijp. This resulted in the detection of at least 22 new events.","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:6ec73a1d-8eee-4b22-a893-e783d118e06f","http://resolver.tudelft.nl/uuid:6ec73a1d-8eee-4b22-a893-e783d118e06f","Electromagnetic heating assisted energy storage: Laboratory study","Kalpoe, Jash (TU Delft Civil Engineering and Geosciences)","Zitha, P.L.J. (mentor); Heller, H.K.J. (mentor); Delft University of Technology (degree granting institution)","2021","Energy storage is increasingly becoming a possible solution worldwide to aid the energy supply and demand. The objective of this study is to determine whether thermal energy storage can be effectively and efficiently achieved by ways of electromagnetic (EM) radiation. To serve this purpose, an experimental setup was designed in order to subject core flooding experiments to EM heating using a MW source. Temperature data is obtained and used to construct temperature profiles as well as energy absorption and storage profiles. The experiments vary from EM radiation under no flow conditions to experiments inducing flow in order to determine the effect of flow on energy absorption and storage amounts. The results obtained show that a significant amount of energy is absorbed by the core and that the introduction of flow at the chosen flowrates during EM heating does not diminish the energy absorption ability of water inside the core. Flow does however increase the rate of energy decline within the core when EM heating is stopped thus reducing the amount of energy stored. Nevertheless, around 40% of the energy absorbed after 150 seconds of EM heating is stored in the core after a cooling period of 60 minutes. This amount declines significantly when flow in implemented throughout heating and cooling. Even though the experimental setup performed accordingly, the large amounts of energy losses are an area that should be subject to improvement. When this technology is implemented in reservoirs or aquifers, the MW antenna is placed in the pay zone. This results in lower energy losses due to the over- and underlying formations functioning as insulation. Subject to improvements, this study concludes that EM stimulated core flooding is a legitimate and viable technology with significant potential for thermal energy storage purposes.""","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:d7c05557-80f4-4ef1-a833-ae70f1fdc44a","http://resolver.tudelft.nl/uuid:d7c05557-80f4-4ef1-a833-ae70f1fdc44a","CO2 degassing of geothermal fluids during coreflood experiments","Verweij, Cas (TU Delft Civil Engineering and Geosciences)","Pluymakers, A.M.H. (mentor); Boeije, C.S. (graduation committee); Zitha, P.L.J. (graduation committee); Bruhn, D.F. (graduation committee); Delft University of Technology (degree granting institution)","2021","In the energy transition from fossil fuels to less polluting renewable energy sources geothermal energy are considered as a promising technology. Gasses such as CO2 are often dissolved in geothermal waters. With the extraction of these fluids from the reservoir, a change in pressure will occur towards the extraction well which may cause dissolved gas to exsolve. The exsolved gas may clog the pores of the reservoir rock near the extraction well and therefore reduce the effective permeability, which can result in reduced production of geothermal waters. This project is aimed at experimentally investigating the conditions of the onset of the degassing process and what the influence of the degassing process is on the permeability. Therefore Bentheimer and Berea sandstone core flood experiments were performed, using either tap water or brine with different CO2 concentrations (0.2 1.3 mol/L) and at temperatures between 30 and 90°C. Flow rates were varied/kept constant, between 90 2 bar and between 5 and 22 bar respectively.
At 30 °C and up to 50 bar the onset of the degassing process is controlled by Henry’s law, i.e. it is governed by the solubility of gaseous CO2. The onset of the degassing process is not influenced by the pore size and initial permeability. At these conditions the effective permeability decreases by a factor 2 to 5 in the Bentheimer sandstone core and by about a factor 10 in the Berea sandstone core. This change in effective permeability is gradual in the Bentheimer sandstone while in the Berea sandstone the change is nearinstant. For rocks with small pore sizes and low initial permeability, the reduction in effective permeability is larger and the rate of permeability decrease is faster.
Experiments at temperatures between 30 and 90°C show that with increasing temperature Henry’s law becomes increasingly inaccurate to find the onset of the degassing process. The onset degassing pressure increases with temperature but are significantly lower than Henry’s law. This inaccuracy can partly be explained by the fluid in the core not reaching the right temperature or by the values used for extrapolating Henry’s law for different temperatures. In experiments performed with a 1M NaCl brine the pressure at which the degassing process starts is higher than for experiments performed with tap water. The increased salinity does not influence the change in effective permeability due to degassing. The reason for this is that the change in interfacial tension between CO2 does not change sufficiently between tap water and Brine to cause differences in the degassing process.
The results obtained from this research can be used for successful management of geothermal projects. It shows at what conditions the degassing process starts and what the effect of this process is. Once the conditions are known they can be avoided. The research also shows the degassing process and its effects can be reversed.","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:0acea55f-1fc0-49dd-94fd-a90e3b36fd2e","http://resolver.tudelft.nl/uuid:0acea55f-1fc0-49dd-94fd-a90e3b36fd2e","A study of starvation and dormancy of phosphate accumulating organisms and its effect on the Nereda® wastewater treatment: A study of starvation and dormancy of phosphate accumulating organisms and its effect on the Nereda® wastewater treatment","Sarah Jacob, Sarah (TU Delft Civil Engineering and Geosciences)","de Kreuk, M.K. (mentor); Pronk, M. (graduation committee); van den Berg, Lenno (graduation committee); Delft University of Technology (degree granting institution)","2021","Dormancy is a topic that is researched extensively for various microorganisms, especially in the field of medicine. However, not many studies have been conducted for the dormancy of microorganisms in the wastewater treatment sector. Treatment processes like the NEREDA® technology use Phosphate Accumulating Organisms (PAO) to remove phosphate from the wastewater. If dormancy affects these bacteria, it can cause the wastewater treatment plants to function at a lower capacity. Reviving dormant PAOs can increase treatment capacity and treat the wastewater during high influent loading without effluent deterioration. Studying the optimal conditions for granule storage without inducing dormancy can be advantageous during granule transport for inoculation of reactors during their start-up phase. This study presents the first independent assessment of the possible dormancy of PAOs in Aerobic Granular Sludge (AGS).
In this research thesis, dormancy is a survival strategy opted by PAOs to persist substrate limitation. There are two different pathways to dormancy that has been explored here. Responsive switching and starvation are studied as they express fast and slow transition respectively into dormancy. Lag faced during resuscitation of dormant cells is considered proportional to the length of dormancy in responsive switching.
The experimental phase of the research can be interpreted in three parts: first through method development, second through method testing and third through the application of the developed method. The method was developed to understand dormancy in PAOs by observing differences in their maintenance and activity rates. This method was then tested on granules where dormancy was induced by lowering the temperature to 4ºC and anaerobically storing without feed. This method was then applied to newly sampled granules from a full-scale reactor to study dormancy in the PAOs. The developed method increased the activity of the former granules by 60% but did not raise the activity of the latter. Maintenance rates increased by 167% and 68%, respectively, in the granules. Although dormancy could not be sufficiently proved by the method, starvation of PAOs in Utrecht NEREDA® reactors was possible.
Two techniques were used to model the subsurface fracture network: paleo-tectonic stress inversion and fracture network forward modelling techniques. The modelled DFN resembles the fractures geometry at the well location whereas away from the well the model is constrained by the subsurface fault geometry and far-field tectonic stress. Moreover, the modelled DFN consists of multiple 2 meters thick layers where each layer include a layer-bound fracture network. One of the main limitations of this approach is that it can not consider multiple tectonic regimes to simulate the fracture network. In addition, this approach requires large computational power.","Geothermal Exploration; Natural Fracture Networks; discrete fracture network; Geomechanical Modelling; Geneva Basin; Lower Cretaceous Carbonates","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:85defc82-74d7-4cc8-a7b9-5fc41a233f45","http://resolver.tudelft.nl/uuid:85defc82-74d7-4cc8-a7b9-5fc41a233f45","Spatial and temporal variability of hydrological behaviour and leachate composition in a landfill stabilized by in-situ aeration: An experimental and numerical study on the cause and mitigation of reduced aeration efficiency","de Jong, Ties (TU Delft Civil Engineering and Geosciences)","Gebert, J. (mentor); Heimovaara, T.J. (graduation committee); Bogaard, T.A. (graduation committee); Lammen, Hans (graduation committee); Delft University of Technology (degree granting institution)","2021","""Landfills form the final stage in waste processing and are sources of multiple environmentally harmful emissions. Due to the biodegradation of organic material, methane, a strong greenhouse gas, is released into the air and soluble pollutants, like ammonium or heavy metals, are flushed out of the landfill waste. In modern landfills, the waste body is isolated from the environment by an impermeable liner and both the gas and the leachate fluxes are collected and treated. However, sealing the landfill reduces the emissions on the short term but gives no sustainable solution as eternal active aftercare is needed and the emission potential is not reduced. The goal of the CURE project is to develop methods to enable the sustainable management of Dutch landfills. One of these methods is piloted at the Braambergen landfill, which is the in-situ aeration of the waste body with the goal of speeding up the biological degradation of organic matter to reduce the emission potential relatively quickly below the values in the Dutch regulations, such that the eternal active aftercare is not required anymore. The issue that the landfill operator, Afvalzorg, is facing is that in compartment 11Z of the landfill the aeration efficiency is poor due to ponding leachate. The objective of this thesis is to quantify the relation between the water level in the landfill and the efficiency of aeration, and to research the spatial and temporal variability of the water levels, leachate composition and hydraulic conductivity of the waste body to investigate the nature of the water and to find a suitable solution to mitigate the reduced aeration efficiency. To reach this goal, multiple types of field and lab measurements have been performed and the results of a water balance model have been used for a numerical evaluation. In the field, water tables have been measured as well the magnitude and composition of landfill gas extracted by the aeration wells. Pumping tests have been performed on the wells to assess the hydrological behaviour of the leachate surrounding the wells and to determine the horizontal hydraulic conductivity of the waste. Leachate samples from all the wells have been collected and analysed in the lab on pH, redox potential, electrical conductivity, DOC and ammonium concentration. Also were CTD-divers installed in some of the wells to monitor the response to rainfall and the medium long term behaviour of the water level and the electrical conductivity. The general conclusion of this thesis is that the studied compartment 11Z is homogenous in its heterogeneity. With all the different measurement types performed it was in some way the objective to see whether the behaviour or the properties of the landfill and the leachate can be grouped spatially, but this was not the case. Therefore can be concluded that the only scale for which a measurement can be representative for the entire compartment is on the scale of the compartment itself. This is in line with the expectations of large heterogeneity in landfills and the unique situation of aeration system on the Braambergen made it possible to proof this. The efficiency of the aeration system is particularly low in compartment 11Z because the conditions are unfavourable for both water and gas flow. The conditions in compartments 12 and especially 11N are more favourable because the waste, especially at the bottom of the compartments, is more permeable. Even if the amount of water in 11Z is reduced and the gas flow increases, the total amount of extracted LFG will not reach the same level as for the other compartments.","Landfill; Hydrological processes; Spatial variability; Temporal variability; Leachate composition; Water balance model","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:f0bf0e1b-7b5e-4cd1-853a-e0eeb1ff61c9","http://resolver.tudelft.nl/uuid:f0bf0e1b-7b5e-4cd1-853a-e0eeb1ff61c9","A visual assessment tool for mine development: The development of an evaluation tool to compare the visual impact of opencast mining operations in the pre-feasibility phase","van Hooijdonk, Eva (TU Delft Civil Engineering & Geosciences)","Buxton, M.W.N. (mentor); Keersemaker, M. (graduation committee); Blom, J.C. (graduation committee); Lottermoser, Bernd (graduation committee); Rinne, Mikael (graduation committee); Delft University of Technology (degree granting institution); Rheinisch-Westfälische Technische Hochschule (degree granting institution); Aalto University (degree granting institution)","2021","Surface mining operations can have a significant visual impact on the surrounding landscape and communities. There have been numerous cases of local populations pushing back against the development of mining operations near their communities. This study aims to determine whether it is possible to assess the visual impact of surface mining operations before the development has started. With this assessment it would become possible to make informed decisions as to pitshell development and selection in terms of visual impact. A tool was developed to determine whether it is possible to make this assessment. This tool must be able to be used to determine the visual impact of two or more scenarios in the pre-feasibility phase of development to assist in the decision of
which scenario will be developed further in the feasibility phase. In this context, the visual impact is defined as the perceived change in the landscape as a result of mine development on local communities around the surface mine development. The scenarios are defined as the option of pitshells designed during the pre-feasibility phase of mine development.
The tool makes a distinction between the physical changes in the landscape caused by the surface mining operation and how this physical change is perceived by anyone viewing the operation.
The tool is GIS based and utilizes the free open-source software QGIS to calculate the physical change in the landscape. The tool calculates the vertical and horizontal visibility angle. The visibility angle describes the extent that the change in the landscape takes up in the view of an observer. In addition
to that, the tool calculates the contrast between the changed colour in the landscape and its surroundings, which describes how much the change stands out. It requires two sets of data to work: a digital elevation model of the prospected surface mine pitshell and the surrounding landscape and a
RGB satellite image of the surrounding area. The DEM provides elevation data for every square metre of the landscape to the GIS, while the satellite image provides RGB colour data. All other data can be generated from the previously mentioned data features.
The tool is tested using a case study, in which several distinct pitshell scenarios are compared against one another on their visual impact. The case study is based on the extension of a limestone quarry in
Belgium, which aims to secure reserve for future operations. The area of interest is surrounded by several small to medium size villages, which would be affected visually by the extension. Therefore, a comparison should be made regarding the visual impact of the several pitshell scenarios. The results showed it is possible to determine the visual impact of surface mining operations before the
development has started. On this basis, it is possible to compare different pitshell scenarios and determine which scenario would be least impactful in terms of visual impact on the local community and surrounding landscape. The reliability of the tool can only be assessed theoretically, however a high level of accuracy is achieved by adhering to guiding principles which are set out in this thesis.","Visual impact; Landscape; Opencast; Mining; LVIA; pre-feasibility","en","master thesis","","","","","","","","2022-07-22","","","","Applied Earth Sciences","",""
"uuid:2ee4419a-5f3d-4039-834f-7332d8bc90c8","http://resolver.tudelft.nl/uuid:2ee4419a-5f3d-4039-834f-7332d8bc90c8","Quantified Characterization of Discrete Fractures through Surface Roughness, Surface Area, and Hydraulic Conductivity","Reijm, Cornelis (TU Delft Civil Engineering and Geosciences)","Dieudonné, A.A.M. (mentor); Barnhoorn, A. (graduation committee); Delft University of Technology (degree granting institution)","2021","Argillaceous (clay-rich) host formations for radioactive waste geological repositories are extensively researched for their capability to decrease the hydraulic conductivity of fractures over time (i.e. self-sealing). This self-sealing behavior is beneficial in the context of radioactive repositories as the excavation of these spaces unavoidably induce fractures in a region called the excavation damaged zone (EDZ), allowing for radioactive particles to leak into the surrounding environment and groundwater. Despite knowing the mechanisms for self-sealing (e.g. swelling of clay minerals), more research is needed into the complexities of self-sealing to fully understand and effectively utilize it widely. To facilitate research of swelling in induced fractures, a quantified method of fracture characterization using morphological descriptors is developed to provide insight into the morphological state of the fracture surface and its influence on the self-sealing capacities of argillaceous rocks. This was carried out by identifying morphological descriptors of a rough surface and their relation to roughness, as it pertains to macroscopic and microscopic roughness. A dynamic script was developed capable of: analyzing and quantifying morphological descriptors of roughness in 2 and 3-dimensions, calculating the surface area of a rough surface, and calculating hydraulic conductivities (kx and ky) of a discrete fracture. This method was tested using two samples of Opalinus Clay (OPA) from the Mont Terri underground research laboratory (URL) in Switzerland. Furthermore, derived data of heterogeneous morphology, along with surface area and hydraulic conductivity, is used to discuss the limitations and constraints of the developed method and compare 2-dimensional versus 3-dimensional morphological analysis to determine what combination of analysis fully captures the breadth of morphological information. It was determined that the morphological descriptors of amplitude, amplitude density, and the bearing area curve (BAC) are suitable descriptors to define the microscopic and macroscopic roughness of a rough surface, where both forms of roughness are defined in the context of influence from local maximums (asperities) and local minimums (valleys) of the surface. Comparison of the 2 and 3-dimensional analyses of these morphological descriptors shows that a combination of the 2D BAC, 3D amplitude, and 2D amplitude densities both fully capture the breadth of morphological information and provide an easier means of interpretation. Using Delaunay triangulation on the surfaces of both OPA samples, the calculated upper and lower bounds of surface area for sample 1 is: 2267.37mm2 and 942.09mm2 and is: 2377.64mm2 and 959.73mm2 for sample 2. Compared to the planar surface area of each OPA sample analyzed, this corresponds to an 847 - 2039% increase for OPA sample 1 and a 998 - 2399% increase in surface area for OPA sample 2. The calculated hydraulic conductivities kx and ky for sample 1 is: 1.78×10−7 m/s and 7.75×10−7 m/s and is: 8.01×10−9 m/s and 2.1×10−7 m/s for sample 2. This is compared to the hydraulic conductivity of the Opalinus clay material, which is 2×10−13 m/s. Future research into discrete fracture characterization using morphological descriptors should focus on increasing the computational efficiency of the existing code, improving the surface area calculations, and transforming the matrices of data into one points of data for easier comparison of discrete fractures across multiple samples. In doing so, it is hoped that this small contribution will aid in understanding morphology influence on swelling development in induced fractures in argillaceous geomaterial.","Argillaceous; Quantified Characterization; Discrete Fracture; Swelling; Opalinus Clay; Fracture Descriptors","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:83306209-2405-43a0-9baa-f1793136c2b3","http://resolver.tudelft.nl/uuid:83306209-2405-43a0-9baa-f1793136c2b3","Using Machine Learning to Predict Facies Associations from Wireline Logs for the Carboniferous in the Southern North Sea","Albeesh, Deema (TU Delft Civil Engineering and Geosciences)","Abels, H.A. (mentor); Martinius, A.W. (graduation committee); Barnhoorn, A. (graduation committee); Delft University of Technology (degree granting institution)","2021","The use of wireline facies associations can alleviate core data shortage during facies prediction by providing a more extensive input dataset. Wintershall has assigned wireline facies associations directly on cored and un-cored wells in the Carboniferous of the Sothern North Sea. Conducting facies prediction using these wireline facies associations as an input can help with tapping into the remaining exploration and development potential of the area. However, the accuracy of this input must be evaluated using core data before machine learning algorithms are applied. This was quantified as 71% for 9 cored wells, where the background floodplain and braided channel facies had the highest accuracies of 88% and 81% respectively, and the mouth bars and marine shales facies could not be adequately validated due to their insufficient core sampling. Consequently, when using wireline facies associations for training facies prediction algorithms, this input’s intrinsic uncertainty should be accounted for while examining the outputs, especially for facies that are not sufficiently validated by cores. Applying facies prediction with Support Vector Machine (SVM), Multilayer Perceptron Neural Network (MLP) and Recurrent Neural Network (RNN), showed that RNN can achieve the highest overall accuracy of 80.9%, due to the highest F1 scores for braided channel (0.88), point bars (0.60) and coal (0.53). The class imbalance problem is apparent for this dataset where the majority classes of background floodplain, braided channel, point bar and coal, are more predicted than the minority classes of crevasse splay sands, mouth bars, and marine shale. Applying RNN on the Westphalian A, B and C separately served as a form of imbalance correcting technique that increased the F1 scores of underrepresented facies. Future work can further refine the results by exploring imbalance correcting techniques through under-sampling the background floodplain and over-sampling the crevasse splay, mouth bar and marine shale facies.","machine learning; Facies Prediction; North Sea; Lithofacies","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:2e5dfc75-d7b8-44bd-a1f3-99f2b18f3533","http://resolver.tudelft.nl/uuid:2e5dfc75-d7b8-44bd-a1f3-99f2b18f3533","Sediment bypassing at Ameland inlet: And the role of an ebb-tidal delta nourishment","Lambregts, Paula (TU Delft Civil Engineering and Geosciences)","Wang, Zhengbing (graduation committee); van Prooijen, Bram (graduation committee); Storms, J.E.A. (graduation committee); Pearson, S.G. (mentor); Elias, Edwin P.L. (mentor); Pluis, Stefan (graduation committee); Delft University of Technology (degree granting institution)","2021","A large part of the Dutch coast, the barrier islands in the Wadden Sea included, would be eroding if the deficit in the total sediment budget was not compensated for through nourishments. Ebb-tidal deltas have an important function within the coastal system that make them of interest for coastal defence as a source and transport path for sand to the back-barrier basins and the island coastlines. As part of the Kustgenese 2.0 project, a pilot nourishment of 5.5 million m3 has been placed on the Ameland ebb-tidal delta. Improved understanding of sediment bypassing processes and the interaction with a nourishment is needed for strategic placement of nourishments in the future. In this thesis we analyse the high-frequency bathymetric dataset available at Ameland inlet between 2005 and 2020 and model the tide- and wave-driven transport pathways using to SedTRAILS to determine how sediment bypassing works under natural circumstances and under the influence of a nourishment. A new series of conceptual models has been proposed. These show that the formation and growth of a series of ebb-shields on the western side of the ebb-tidal delta plays an important role in sediment bypassing. Their development gradually results in transport pathways connecting the western side of the ebb-tidal delta to the major transport pathway along the ebb-delta front, which forms a direct connection to the Ameland coast in 2017. The influence of the pilot nourishment on sediment bypassing processes is limited, adding volume to the system but not altering the existing transport pathways. Transport pathways show that sediment from the nourishment eventually reaches the Ameland coast and is unlikely to feed the Terschelling coast or the tidal basin. This is valuable knowledge for the future sustainable coastal management of Ameland inlet, which can also be extended to other inlets.","ebb-tidal delta; Ameland Inlet; nourishment; SedTRAILS; Coastal Engineering","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:141a6408-e43d-4370-9204-449e7ab4c76a","http://resolver.tudelft.nl/uuid:141a6408-e43d-4370-9204-449e7ab4c76a","Evaluating the influence of cyclical versus non-cyclical fluvial sedimentation on geothermal flow","Doff, Jelmer (TU Delft Civil Engineering and Geosciences)","Abels, H.A. (mentor); Voskov, D.V. (mentor); Storms, J.E.A. (mentor); Delft University of Technology (degree granting institution)","2021","To produce accurate 3D fluvial architecture models, it is important to understand the influence of internally generated autogenic controls versus externally generated allogenic controls. When studying a fluvial system, autogenic controls such as river meandering and avulsions generally dominate over 103-104 years. Allogenic controls such as climate change and tectonics dominate more at time scales of 105-106 years. A dominant control is astronomical climate change that may produce cyclical fluvial sedimentary successions. The resulting alluvial architecture of autogenic and of allogenic forcing is highly different and it is expected to largely influence geothermal flow through fluvial reservoirs. The aim of this research is to depict the impact of allogenic (cyclical) versus autogenic (non-cyclical) fluvial sedimentation on geothermal flow. Process-imitating and stochastic based modelling software Flumy is used to generate fluvial facies models where either hypothetical cyclical forcing or hypothetical non-cyclical forcing was the dominant force. These models are subsequently tested for geothermal flow using DARTS (Delft Advanced Terra Simulator). We find that the Flumy numerical model can be used to produce hypothetical cyclical and hypothetical non-cyclical alluvial architecture. The main difference between the architectures is the shape of the sand bodies. The cyclical model has overall thicker, laterally wider sand bodies. The non-cyclical model has thinner, less wide, but more often connecting sand bodies. Geothermal flow modelling shows that matching N/G in the cyclical and non-cyclical model in the 20-40 % N/G range gives similar pressures at a constant, fixed water rate. This points to the hypothesis that, at comparable N/G, the well connectivity must also be similar. The non-cyclical model breakthrough times in the 20-30 % N/G range are generally equal or slower, compared to the cyclical model. This gives credence to the hypothesis that the cyclical model has overall equal or slower flow paths between the well connections in the geothermal doublet. The difference in flow path hypothesis can be properly tested through visualizing 3D streamlines and is a recommendation for the future.","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:8f5705b2-7c5b-418d-b63b-f0a21ba4b27f","http://resolver.tudelft.nl/uuid:8f5705b2-7c5b-418d-b63b-f0a21ba4b27f","Impact analysis of Capesize vessels on ArcelorMittal Ghent","van Erp, Huub (TU Delft Civil Engineering and Geosciences)","Buxton, M.W.N. (mentor); Soleymani Shishvan, M. (graduation committee); van Hassel, E.B.H.J. (graduation committee); van Hove, An (graduation committee); Delft University of Technology (degree granting institution)","2021","The enlargement of the lock complex of Terneuzen in 2023 will allow Capesize vessels up to 300 meters in length, to access the Ghent-Terneuzen canal and reach the quay of ArcelorMittal Ghent (AMG). The goal of this thesis is to estimate to what extent these vessels can be used, the impact that these vessels will have on the supply chain and the cost impact of the implementation of Capesize vessels. The production of AMG is expected to be increased up to 5.5 million ton of steel for 2026. Therefore, it will require an estimated 12.9 million ton of raw materials (12% increase compared to 2019) which mainly consist of iron ore and coal. Up to 31% of this material can be shipped from source ports that are accessible by Capesize vessels. The draught restriction of 12.5 meters for the canal, limits the amount of bulk material that can be unloaded by the Capesize vessel to 105,000 DWT which is 60% of the maximum of 175,000 DWT. The remaining 70,000 tons of material can be unloaded externally and be transported to AMG by the use of inland barging vessels. The increased volume of Capesize vessels compared to the current Panamax vessels will lead to an increase in load size and a decrease in load frequency which will affect the downstream installations of AMG. Most of the current quay cranes will be unable to unload Capesize vessels due to the increased size of the ships. A proposed crane was introduced in the model to examine the ideal positioning to unload Capesize vessels and barges. 6 realistic scenarios for 2026 have been examined with varying levels of Capesize utilization. As a result of these scenarios vessel arrival lists for full year were simulated. Each of the vessel lists served as input data on a quay model with as results the downstream impact. The main output parameters were the waiting time for sea vessels, waiting time for barges and the amount of material that had to be stored on a temporary storage. In general, the implementation had a negative effect on all three of the output parameters resulting in additional quay costs. The net effect of Capesize vessels on the total costs was positive thanks to the lower shipping price per ton of material. This benefit was partly compensated by the increased costs for barging that was caused by Capesize transport. The shipping costs for Capesize vessels should at least be 2.53 dollar per ton cheaper, to break-even with Panamax vessels. Under current circumstances the full-scale use of Capesize vessels can be feasible. However due the high volatility of the dry bulk market and bunker prices, it is impossible to guarantee this will be the case for 2026.","Capesize; Vessel Logistics; Ferrous Industry; Supply Chain","en","master thesis","","","","","","","","2022-04-30","","","","Applied Earth Sciences","",""
"uuid:32068148-350f-4dac-80f8-cbe1250b9e49","http://resolver.tudelft.nl/uuid:32068148-350f-4dac-80f8-cbe1250b9e49","InSAR-based analysis and monitoring of hazardous glacial lakes in the Himalaya","van Hout, Ylana (TU Delft Civil Engineering & Geosciences)","Giardina, Giorgia (mentor); Whitworth, Michael (mentor); Malinowska, D.U. (graduation committee); Milillo, Pietro (graduation committee); Askarinejad, A. (graduation committee); Lhermitte, S.L.M. (graduation committee); Delft University of Technology (degree granting institution)","2021","Glacial lake outburst floods (GLOFs) are outbursts caused by the failure of glacial lake moraine dams. Longer ongoing processes, such as moraine dam degradation, or instantaneous events, such as landslides, can trigger dam failure. GLOFs have a catastrophic downstream impact leading to significant economic damages and more than 12000 casualties worldwide until 2015, with Bhutan and Nepal being impacted the most. Climate change causes increasing temperature and precipitation, leading to the expansion of glacial lakes and the destabilisation of glaciers, slopes and moraine dams. Consequently, GLOFs are likely to become more frequent, and glacial lakes require continuous monitoring and analysis to understand and predict GLOF-related hazards.
Since glacial lakes often lie in inaccessible mountainous regions, on-site monitoring is challenging and remote sensing proposes a safe and cost-effective solution. Satellite radar is unaffected by nighttime and clouds, enabling continuous displacement measurements. Interferometric synthetic aperture radar (InSAR) using Sentinel-1 data from 2014 to 2021 was applied at six Himalayan glacial lake areas (Imja, Lunana, Barun, Rolpa, Thulagi and Lumding) to identify potential GLOF hazards and to investigate InSAR's capability as a monitoring tool. Optical, meteorological and topographical data were used to aid in interpreting the InSAR observations; linking displacements to potential hazards and evaluating the limitations of an InSAR-based analysis.
Significant deformation was detected at the terminal moraines of Imja, Thulagi, Rolpa, Lunana and Barun Lakes; on lateral moraines at Rolpa and Lunana Lakes; and on rock glaciers at Imja, Rolpa, Barun and Lunana Lakes. In addition, significant seasonal variation could be distinguished, showing the impact of temperature and precipitation on geomorphological processes and potential hazard developments at glacial lakes. InSAR-related limitations arose in regions with significant topographic variations, extant snow or vegetation covers, and rapid displacements.
This study demonstrates the capability of satellite InSAR as a glacial lake monitoring tool. An InSAR-based analysis is instrumental in highlighting areas from where GLOFs could originate, requiring mitigation measures or further investigation to map the impact of failure. By extending the research frame over multiple years, continuous and long-term monitoring could demonstrate the climatic influence on displacements and GLOF trigger developments.","InSAR; GLOF; Himalaya; PSI; Sentinel-1; glacial lake monitoring; outburst susceptibility","en","master thesis","","","","","","","","2024-04-25","","","","Applied Earth Sciences","",""
"uuid:4d7c5b96-a5a2-4b29-8a82-ae6bb12f6cb6","http://resolver.tudelft.nl/uuid:4d7c5b96-a5a2-4b29-8a82-ae6bb12f6cb6","The influence of installing UTES boreholes on the bearing capacity of piles","Griffioen, Pieter (TU Delft Civil Engineering and Geosciences; TU Delft Geo-engineering)","Vardon, P.J. (mentor); Gavin, K.G. (graduation committee); Bloemendal, J.M. (graduation committee); Ammerlaan, P.R.M. (graduation committee); Profittlich, M. (graduation committee); Hoefsloot, F. (graduation committee); Delft University of Technology (degree granting institution)","2021","The transition to renewable energy has lead to many new ways of energy production, such as wind and solar energy. For solar energy power, there is an excess of energy during summer and an deficiency of it during winter, which is reversed for the energy consumption. In order to amend this problem, there is an introduction of new ways of energy storage in the form of heat for domestic and industrial use. One of these is the use of Underground Thermal Energy Storage (UTES). These systems make use of the underground to store heat during summer and extract heat during winter by using a fluid as the heat transferring agent. There are many different ways of UTES installation, however there are two which are widely used in the Netherlands: 1) Aquifer Thermal Energy Storage (open systems) which are based on heat-transfer by convection and 2) Borehole Heat Exchangers (closed systems) which are based on heat-transfer by conduction. While the way of transferring heat differs, they both need vertically drilled boreholes to reach a certain storage depth. These boreholes are drilled close to, or underneath, pile-founded buildings. The drilling of boreholes influence in-situ soil stresses around them, which might influence the bearing capacity of the piles. The aim of this thesis is to investigate the influence of installing UTES systems on the bearing capacity of piles. This is done by: 1) investigating the stress changes in sand due to the drilling of boreholes (stress analysis) and 2) the influence of these stress changes on the bearing capacity of piles (bearing capacity analysis). All of the modelling was done in PLAXIS, by using the 2D-axisymmetric model for the first part and the 3D plane strain model for the second part. An advanced soil model for sand was used, with soil mechanical behavior according to the Hardening Soil small strain model. The stress analysis consists out of a parameter sensitivity analysis, including the key parameters: back-fill grout shrinkage and expansion, Over-Consolidation Ratio and Relative Density. After this, the influence of the borehole fluid pressure and borehole diameter on the stress states were investigated. As not all boreholes are drilled perfectly, the last part of the stress-analysis takes into account drilling complications. The bearing capacity analysis includes simulations of static pile load tests of non-displacement piles. Load-displacements curves are produced for several scenario's: 1) perfectly drilled boreholes, 2) boreholes with drilling complications, 3) influence of a soft soil layer and 4) displacement piles and the influence of a varying installation phasing. The results indicate no large effects of perfectly drilled boreholes on bearing capacity of piles located outside a zone of 1.5 times the borehole diameter. For boreholes with drilling complications, the bearing capacity is influenced for piles located in a zone of influence of only several meters (2-6m), depending on the severity of the complication. At last, loaded piles of existing buildings are extremely sensitive for stress changes due to the drilling process, which will cause severe loss of bearing capacity.","bearing capacity; (non-)displacement piles; UTES; boreholes; ATES; BHE; BTES; drilling complications","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:d2ec6475-f499-4aa2-b82f-70c897c3f741","http://resolver.tudelft.nl/uuid:d2ec6475-f499-4aa2-b82f-70c897c3f741","Ammonia recovery from calciner off-gas: The effect of reclaiming ammonia by direct injection into the plant system","Lohle, Wout (TU Delft Civil Engineering & Geosciences)","Rem, P.C. (mentor); Buxton, M.W.N. (graduation committee); Bakker, M.C.M. (graduation committee); Delft University of Technology (degree granting institution)","2020","Ammonia has been recognized as an effective leaching agent in hydro-metallurgical processes for the recovery of metals\cite{AmmLeach2013}. These processes result in ammonia-metal crystals, whereby in the last step, water and ammonia are removed from the crystals by a calcination process. In the past, the vaporized ammonia is considered a waste stream. However, regulations in the last few decades make it impossible for companies to dispose large amounts of ammonia into the air\cite{LRTAP2005}\cite{SOER2020}. Therefore, expensive installations, like catalytic oxidizers (CATOX) or membrane separators, need to be installed for ammonia reduction in the effluent gas stream. Climax Molybdenum b.v. installation in the Botlek Rotterdam produces pure molybdenum oxide according to the process described above. With the production, molybdenum oxide is leached in an ammonia solution to remove all contaminants, then crystallized and calcined. For the calcination process, the crystals are heated by a gas burner to vaporize the ammonia and water. The off-gas contains air, \ce{NH3}, \ce{CO2}, dust particles, and water vapor. The objective is to recycle the ammonia from the off-gasses of the calciner. Reclaiming the ammonia from the off-gas stream could reduce the costs up to \euro2000 per day. In this thesis, insights are gathered related to the chemical and physical reactions that occur when off-gasses of the calciner enter the process. Additionally, both the beneficial effects and potential complications of reclaiming ammonia from the off-gas are explained. This research is conducted by making mass balances on three different options for off-gas handling. These options include absorption into the leaching fluid (ARS:Ammonia Reduction System), absorption by water through a scrubbing system (AER:Ammonia Emission Reduction), and absorption by water through a scrubbing system with additional carbon dioxide removal with sodium hydroxide (AER+NaOH). In order to understand what happens when inorganic carbon (IC) comes into the system, experiments are conducted on both the leaching procedure of molybdenum and the stripping and condensing process of ammonia. Results show that inorganic carbon reaches its solubility in the leaching fluid at 2.12 mol/kg. Also, no effect on the solubility of ammonium molybdate was found, and no additional precipitation occurs on metals like zinc, calcium, magnesium, and iron. In the leaching fluid, the solubility of ammonium bicarbonate is reached at 183 grams per liter. Additionally, the influence of inorganic carbon on the stripping process showed that the strip rate of ammonia was reduced by 1.4. Also, could be concluded that stripping of ammonia was done efficiently at 80 degrees until the total ammonia nitrogen (TAN) mole concentration equals the total inorganic carbon (TIC) mole concentration. As a result, additional water treatment is needed for the discharge water to ensure the amount of ammonia does not exceed 25kg per day. Furthermore, another complication found was scaling. Scaling happens in both ARS and AER-system in the form of ammonium bicarbonate. In contrast, AER+NaOH system does not have the complication of scaling or ammonia in the discharge water, but the pH of the solution needs to be neutralized before discharge. Moreover, higher pH in the recycling water of the scrubber causes lower absorption efficiency of ammonia. ARS, AER, and AER+NaOH-system have an ammonia reduction of 41\%w, 33\%w, and 73\%w per day, respectively. For the ARS and AER-system, this means a cost-saving of \euro{1.160,-} and \euro{920,-} per day, respectively. The AER+NaOH-system has a direct cost of \euro{10.130,-} per day, due to the expensive sodium hydroxide. The cost of sodium hydroxide as a water treatment agent is higher than the cost savings of ammonia recovery from the off-gasses of the calciner. Therefore can be concluded that, ammonia recovery from off-gasses has large potential, but other methods are needed to treat ammonia in the discharge water to make it economically feasible. Further research can elaborate on alternatives for ammonia treatment in discharge water. Examples include the use of lime (CaO)\cite{AdPhysicochem2006}, increasing the stripping temperature\cite{Kim2013}, and leaching in sulfuric acid (\ce{H2SO4})\cite{EICforEngin2017}. However, this does not solve the scaling problem in the process. Therefore, further research should shine a light on the reduction of carbon dioxide that enters the chemical plant system. Examples proposed in this research, include condensing ammonia from the calciner off-gas stream. Multiple studies \cite{Xu1999}\cite{Mirl2020} show that, the condensing recovery is more effective for ammonia than carbon dioxide. Furthermore, this research also gives an economically feasible example of using an alternative calcination process without natural gas.","","en","master thesis","","","","","","","","2025-11-27","","","","Applied Earth Sciences","European Mining, Minerals and Environmental Programme",""
"uuid:dcef0d57-5594-4c2d-8d2b-dda75e61b8f7","http://resolver.tudelft.nl/uuid:dcef0d57-5594-4c2d-8d2b-dda75e61b8f7","Geotechnical Bearing Capacity of Timber Piles in the City of Amsterdam: Derivation of bearing capacity prediction factors based on static load tests conducted on instrumented timber piles","Honardar, Siavash (TU Delft Civil Engineering & Geosciences)","Korff, M. (mentor); de Lange, Dirk (graduation committee); Gavin, Kenneth (graduation committee); Ravenshorst, G.J.P. (graduation committee); Spruit, Rodriaan (graduation committee); Op De Kelder, Martin (graduation committee); Hutcheson, Erik (graduation committee); Delft University of Technology (degree granting institution)","2020","class=""MsoNormal"">In the city of Amsterdam, many structures, such as houses,bridges and quay walls, are founded on wooden piles. In order to gain insightinto the safety of such structures, assessment of the foundations is required.As part of an experimental framework assessing the safety of bridges and quaywalls in the city of Amsterdam, a number of piles are instrumented with fiberoptic sensors and load tested in compression. These tests aim to providedetailed information on the behavior of timber piles subjected to loading. Thisinformation can be used to determine the geotechnical bearing capacity of suchpiles. An in-depth analysis is conducted on 8 timber piles tested within thisframework. The conducted analysis has resulted in a variation ofoutcomes. Without including the effects of residual loads, an average baseresistance of 130 kN is observed. Upon inclusion of residual loads the averagetrue base resistance increases to a value of 188 kN. The average shaftcapacities in the bearing sand layer for scenarios excluding and includingresidual effects are 48 and 60 kN respectively. The correlation factor αp is derived usingthree cone resistance averaging techniques. The Koppejan method hasconsistently resulted in the highest derived αp factors withvalues of 1.09 and 1.61 for scenarios excluding and including residual loadsrespectively. The scenario excluding residual effects has resulted in anaverage αsof 0.009 for the bearing sand layer. Upon inclusion of residual loads, thederived αsfactor for the first sand layer amounts to 0.012. This increase in shear forcesis also observed in the Pleistocene peat layer. Therefore, residual loadsredistribute the capacity of the piles by increasing the shaft resistance inthe bearing sand and Pleistocene peat, while simultaneously decreasing theshear stresses in the Holocene layers above. Conclusively, timber pile characteristics such as variationin geometry and mechanical properties have significant effects on the capacityof the piles. Additionally, these variations result in fluctuations in thecalculated load distribution along the pile. Local smoothing of thesefluctuations results in higher apparent loads, most specifically at the pilebase. Therefore, smoothing algorithms are not implemented in this analysis. Thevariation in diameter along the entire length of each pile directly affects theload distribution. Despite this influence, no trend is observed for thevariation of αp factors with respect to pile tip diameter. Anapparent relationship between the tapering of the pile in the bearing sandlayer and the derived αs factors suggests that tapering effectivelyincreases the shear forces along the shaft in that layer. Furthermore, the usage of fiber optic sensors on woodenpiles has proven to be effective. The variation in local behavior of wood isclearly illustrated through the conducted analysis. As a consequence of thebiological nature of wood, the local behavior of wooden piles is best capturedby sensing technologies measuring strains at high spatial frequencies. ","Bearing capacity; Geotechnical Bearing Capacity; Timber piles; wooden structure; Amsterdam; Foundations; Soil-structure interaction; geo-engineering; Fiber optic sensors; Pile load test","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:94c2d220-262d-4eca-a3ae-b8ce7eb72ac1","http://resolver.tudelft.nl/uuid:94c2d220-262d-4eca-a3ae-b8ce7eb72ac1","Geologically relevant framework for adaptive fractured reservoir modeling","Ris, Daan (TU Delft Civil Engineering and Geosciences)","Hajibeygi, H. (mentor); Delft University of Technology (degree granting institution)","2020","It is a great challenge to accurately model the flow through subsurface reservoirs. The fact that they are located a few kilometers below the earth’s surface means that it is very difficult to locate flow affecting phenomena. Fractures are considered to be such phenomena. They can either enhance or block flow which has a substantial effect on the flow through the reservoir. This research addresses the flow properties of fractures and the location of fractures. This research introduces analogue fracture maps to get a grasp on possible fracture locations and introduces a classification of fractures based on their orientation with respect to subsurface stress. Using this classification, fractures are assigned different permeability values, a flow affecting property. Using this approach a fracture map is obtained that can be used to model flow through a reservoir. To model flow, the projection based Embedded Discrete Fracture Model (pEDFM) is implemented. This method uses independent grids for both the matrix and fracture and couples them using a transfer function. Even when using the pEDFM method, the computational costs for running simulations through a field scale model will be too large. Therefor the concept of multiscale is introduced and developed further in this research. This research uses algebraically calculated basis functions to prolong the coarse scale solution to finescale. Besides this, flexible coarsening is introduced for a static Multilevel Multiscale (MMs) modeling approach and for Adaptive Dynamic Modeling (ADM). This allows the user to independently choose coarsening ratios for matrix and fractures. This research shows that fractures can be represented accurately using only two vertices on a coarse grid. This can reduce computational costs. Besides the flexible coarsening, the research shows how the grid refinement scheme can be used in efficiently in multiphase simulations. Using a grid re-finement scheme enables the user to capture a saturation front and to use a multiscale grid at the same time. The grid refinement scheme works most efficiently when the cells belonging to high permeable fractures are coupled to the cells belonging to the matrix. The finescale solution This research finally shows the impact of geological uncertainty. The sensitivity analysis shows how geological uncertainty can have an influential impact on the problem that has to be solved. In the sensitivity analysis it is researched how a change in subsurface stress affects the finescale solutions.","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:9b835343-9844-42f8-b869-b3e1affbdc2e","http://resolver.tudelft.nl/uuid:9b835343-9844-42f8-b869-b3e1affbdc2e","Performance analysis of conventional and next-generation artificial geodetic radar reflectors","Patel, Karsh (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Remote Sensing)","Hanssen, R.F. (mentor); van der Marel, H. (graduation committee); van Leijen, F.J. (graduation committee); Hoogeboom, P. (graduation committee); Delft University of Technology (degree granting institution)","2020","The introduction of artificial reflectors in the areas to be imaged by a radar sensor facilitates interferometric analysis over regions of weak coherence between acquisitions. Traditionally, corner reflectors have been utilized; whose strong and stable scattering characteristics make them suitable for these purposes. Such reflectors also provide flexibility in exerting control over the network of points to be analyzed. However, the use of these reflectors is beset with the following challenges: settlement under self-weight, inefficient drainage retaining excess rain/snow, one setup per track etc. Based on the experiment carried out with several reflector devices at Wassenaar, The Netherlands, here we show that specific next-generation artificial reflectors can address some of the challenges posed by conventional corner reflectors while allowing the integration of measurements from several deformation monitoring techniques. As part of the experiment, a deliberate 7±0.05 mm vertical movement is imparted to radar transponder MUTE-1 which is estimated from Sentinel-1 radar images within 0.01 to 0.69 mm deviation while the line of sight motion and radar cross section change realized as a result of imparting deliberate tilt to DBFm device is estimated within 0.47 mm and 1.7 dBm2 respectively. The displacement results from SAR images for MUTE radar transponders are validated using a ground survey campaign. Displacement results in the horizontal direction (East-West projection) suggests that the location WASS01 housing devices MUTE-1 and DBFT tilts in the western directions (estimates of maximum tilt vary from 0.9 to 1.95 mm) while WASS02 location on which MUTE-2 is installed exhibits an eastward tilt (about 2 mm in magnitude). These tilt motions result from the susceptibility of concrete foundation design to swelling and shrinkage of soil. By analyzing meteorological data in conjunction with SAR results from installed devices, we find that the impact of heavy rain remains limited to the conventional reflector type, suggesting that the downward-pointing design of DBF CRs drains the water preventing its accumulation in the apex. Comparative stability analysis demonstrates that next-generation reflector devices (MUTE-2, DBFT and DBFX) can be utilized to determine motions in the vertical and horizontal direction and detect changes in orientation of the device over a vegetation area with low backscattering characteristics with sub-millimeter precision. We anticipate this study to be a small step towards a more sophisticated ground segment for SAR satellites consisting of reflectors that can adequately provide knowledge about deformation characteristics of the area under investigation.","InSAR; IGRS; Radar Transponders; Double backflip corner reflectors; Corner reflectors; geodesy","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","","52.121, 4.389"
"uuid:c756108d-6cb3-4cd2-b457-2ebc353b6d16","http://resolver.tudelft.nl/uuid:c756108d-6cb3-4cd2-b457-2ebc353b6d16","Investigation of the Relationship between Gas Production and Sediment Properties in River Environments","Oderwald Blázquez, Adrian (TU Delft Civil Engineering and Geosciences)","Gebert, Julia (mentor); Chassagne, Claire (graduation committee); Delft University of Technology (degree granting institution)","2020","In riverine environments under anaerobic conditions, methane and carbon dioxide are produced as a result of biological activity, causing degradation of organic matter. Under aerobic conditions, the bacteria present degrade the organic matter, whereby the concentration of dissolved oxygen may be lowered. Thus, issues experienced in the investigation area (the Port of Hamburg) are hindered construction operations, increased greenhouse gas emissions and the echo-sounding equipment used for sonic-depth finding for ships possibly showing an erroneous depth. The purpose of this investigation was to find out how gas generation and respiration relate to the basic sediment properties and what mathematical model with the highest accuracy can predict gas generation and respiration (separately), while maintaining within a given (precision) error (1%). Gas pressure was measured at the TU Delft for an incubation period of 100 days, which was later used to calculate the gas generation (mg C/g DW) with the use of the ideal gas law. Statistical methods used to analyze the data were: Pearson’s correlation coefficient, multiple regression analysis, adjusted coefficient of determination and error analysis. The results show that both gas generation and respiration have the highest Pearson’s correlation coefficient with TOC. Furthermore, in the multiple linear regression, gas generation had the highest coefficient of determination in a regression between TOC as the primary parameter and iron content (in solids) as the secondary parameter (푅2=0.91495). For respiration, it was displayed in a regression between TOC (as the primary parameter) and copper content in the solids (as the secondary parameter) (푅2=0.881). This concludes that organic matter degradation is driven by the quantity of organic matter. The residual sum of squares showed a decrease from the linear (and non-linear) model to the multiple linear regression model. The prob>|t| value (which determines the probability of error for the multiple linear regression) was much lower than 1% for all parameters in both the gas generation and respiration model, so it can be deduced that the variables are contributing to the model in a statistically significant way. Together with the previously mentioned highest coefficient of determination, the most accurate model for both gas generation and respiration found in this investigation was the multiple linear regression model, although the model for gas generation presented little difference to that of the simpler non-linear model. The exponential nature of the optimal fit for the data suggests that there is a threshold. In areas with low organic matter content, the organic matter present is much less degradable, falling into the “slow” pool category. It is recommended to investigate other mathematical models further. There is a possibility of a more accurate model (possibly a combination of a linear and non-linear model) for both gas generation and respiration which can model the parameters even better (higher coefficient of determination while still remaining within the permitted range of error). Furthermore, it is recommended to find out why the samples listed in tables 6 and 10 deviate more than accepted from the calculated value.","organic sediments; multiple linear regression analysis; total organic carbon","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","BIOMUD","53.5511, 9.9937, 51.9963, 4.3759"
"uuid:7d7cf2e1-60f2-4753-9660-1cb81b7e6fc4","http://resolver.tudelft.nl/uuid:7d7cf2e1-60f2-4753-9660-1cb81b7e6fc4","Estimation of Turbulence Intensity from Cup Anemometer-Based Mean Wind Speed Data via Fractal Interpolation","Alinaghi, Pouriya (TU Delft Civil Engineering and Geosciences)","Basu, S. (mentor); Siebesma, A.P. (graduation committee); Delft University of Technology (degree granting institution)","2020","In the well-known process of the turbine design, turbulence intensity (TI) plays a vital role in prediction of the power output and loads on the turbine's structure. TI is believed to be an important statistical parameter of the wind speed that can be extracted from the signals recorded by the dedicated sensors in the wind energy area. Despite the limitations of the mast-mounted sensors, they are probably more popular than LIDARs in wind energy applications. Although the sonic anemometers are reference tools in measuring turbulent features of wind, they are expensive instruments to be employed in a large-scale. In this regard, the cup anemometers appear to be the most commonly used instruments in the wind energy community. Accordingly, it would be tremendously advantageous if the 1-Hz cup anemometer data can be employed with the synthetic down-scaling idea to build the turbulence-like velocity signal fields. In this research, small-scale fluctuations are constructed via the Fractal Interpolation (FI) technique. In addition, this study aims to assess the compatibility of the FI technique in enhancing the cup anemometer data. The analysis has been carried out for the data collected in September 2018. Through this analysis, it is deduced that the cup anemometer data can be improved using the FI method. Subsequently, by applying the FI method, in most of the cases, the standard deviation values of the cup anemometer data are increased.","Turbulence Intensity; Fractal Interpolation; Cup anemometer; sonic anemometer; Wind Energy","en","student report","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:087da2de-62c1-4489-b943-7c44c40f3fb3","http://resolver.tudelft.nl/uuid:087da2de-62c1-4489-b943-7c44c40f3fb3","Temperature Based Water Content Measurement in Mud (Soil) With Fiber Optics","Van Ballaer, Frederik (TU Delft Civil Engineering & Geosciences)","Meshkati, Ebi (mentor); Vardon, P.J. (graduation committee); Doornenbal, Pieter (graduation committee); Draganov, D.S. (graduation committee); Klitsch, Norbert (graduation committee); Delft University of Technology (degree granting institution); Rheinisch-Westfälische Technische Hochschule (degree granting institution); ETH Zürich (degree granting institution)","2020","This research has demonstrated the applicability of a DTS system to estimate the volumetric water content in saturated mud material. 2 samples of synthetically generated mud and 1 sample of natural mud from the port of Rotterdam were investigated, first by conventional methods and subsequently also with DTS. The system set-up and heating strategy were optimized by testing with different media (air, water) and with different FO coil diameters. A step-by-step approach was then designed to translate the thermal response recorded in the muds into volumetric water contents. Early- and late- time cutoffs were applied to the slope selection procedure (∆T vs ln(t)), and a mud dependent correction factor was applied to obtain the effective heat flux. The average VWC’s (ϴ) subsequently derived from the DTS data were in good agreement with those obtained by conventional methods (core sampling); the standard deviation in the VWC’s (ϴ) of all three tested muds was between 0.030 and 0.040 m3/m3. For saturated conditions, Sayde et al. (2010) and Striegl and Loheide (2012) published larger standard deviations of 0.046 m3/m3 and >0.050 m3/m3 respectively. The approach detailed in this investigation has enabled DTS to perform as a guideline on the continuous volumetric water content profile in saturated muds.","Distributed Temperature Sensing; Volumetric water content; Thermal Conductivity","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:8657c881-7dfb-4179-abbe-184affb97507","http://resolver.tudelft.nl/uuid:8657c881-7dfb-4179-abbe-184affb97507","The influence of suction on the shear strength of a clay dike","Buiten, Hilma (TU Delft Civil Engineering & Geosciences)","Jommi, C. (mentor); Brinkgreve, R.B.J. (graduation committee); Aguilar Lopez, J.P. (graduation committee); Hopman, P. (mentor); van Duinen, A. (graduation committee); Delft University of Technology (degree granting institution)","2020","","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:ddb0bfaa-7e8e-49c5-8f39-0dff3d05c29b","http://resolver.tudelft.nl/uuid:ddb0bfaa-7e8e-49c5-8f39-0dff3d05c29b","Seismic Risk Assessment For Geothermal Projects: With The Creation Of A Physical Screening Model","Nieuwstad, Bas (TU Delft Civil Engineering and Geosciences)","Vossepoel, Femke (mentor); Vardon, Phil (mentor); Delft University of Technology (degree granting institution)","2020","Geothermal energy can be a great solution for the downscaling fossil fuel society, but it can potentially lead to seismic hazards. A doublet system, with a cold water injection well and a hot water production well, alters the stress situation in the subsurface, which can result in (micro)fracturing and fault reactivation. Even in water filled reservoirs, aquifers, with relatively good permeabilities, the acting in-situ stress on already existing fault can be changed such that there can be a seismic hazard. The three dominant phenomena that influence the fault reactivation and are triggered by geothermal water injection and production are the direct pore pressure change, poro-elastic stress change and thermo-elastic stress change. To predict and subsequently diminish or limit the seismic hazards in geothermal operations, Seismic Risk Analysis (SRA) are to be completed before such operations can take place in an often seismic risky location, like densely populated areas. In the current (Dutch) geothermal environment mainly three SRA’s are used; “Methodiek voor risicoanalyse ontrent geinduceerde beving door gaswinning” by the Staatstoezicht op de Mijnen (SodM), “Defining the Framework for Seismic Hazard Assessment in Geothermal Projects V0.1” by Q-con/IF-technology [6] and an Excel-model created by TNO/Geomech. By investigating and reviewing these three SRA’s in this thesis their shortcoming and limitations are exposed, for example their lack of physical foundation and explanatory results. From the foundation of the currently excising SRA’s a new alternative SRA, which corresponds in some steps with the older SRA’s, is created in this thesis. In order to successfully finish the new SRA one of the three steps should be completed, starting with SRA Step 1. In this first step of the new SRA a new Physical Screening Model (PSM) is created. When completing the SRA an indication of what type of seismic monitoring there should be done during production. This PSM is a fairly quick and simple in its use but provides sufficient informative data to investigate the seismic hazard for most geothermal operations in the Netherlands. In four different steps in the PSM, the potential reactivation of faults over the whole reservoir during production will be evaluated. With the spatio-temporal evolution of ΔP, Δσporo, ΔT (PSM Step 1) this model can predict fault reactivation at any place and time inside the reservoir, while it can also look at which parameter dominated this reactivation. In this thesis the physical background and results of the PSM will be explained step by step. Eventually there are three final results from the PSM; a Mohr plot that predicts if certain faults (at certain locations) are stable or not and the maximum Moment magnitude (Mw) in combinations with the Peak Ground Velocity (PGV), which predict the severity of a possible event. Sensitivity analyses and case studies done with the PSM in this thesis show the influence of dominating parameters, like permeability and injection rate, and what results can be expected when using this model.","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:3796ebec-7a17-41ce-b629-eb0416237e30","http://resolver.tudelft.nl/uuid:3796ebec-7a17-41ce-b629-eb0416237e30","Micro-scale effects of stylolite orientation on the motion of tensile failure: A study analyzing strain fields of stylolite limestones using Particle Image Velocimetry","Versluis, Barry (TU Delft Civil Engineering and Geosciences)","Pluymakers, Anne (mentor); Barnhoorn, Auke (graduation committee); Delft University of Technology (degree granting institution)","2020","Many laboratory tests of samples where the rock fractures are based on
meso-scale (cm) characterization of effective ‘intact’ strength parameters neglecting the microstructure effects. Understanding fracturing processes at
micro-scale (mm) will require models with microstructure data. However,
data is lacking on micro-scale.
Stylolites are natural rock-rock interlocked interfaces which form by a localized
dissolution process and their interface contains minerals and material
different from that in the surrounding host rock. Microstructures such as
stylolites influence the tensile stress behaviour in a rock formation. We are
interested in stylolites because they can act as drains or as barriers to flow.
Therefore, we introduce a study where we investigate on micro-scale failure
mechanisms of limestone samples with stylolites in diverse orientations.
In preceding study (Pluymakers et al., pers. comm.) a series of Brazilian
Disc Tests was performed on eleven samples all including stylolites of microscale
carbonate samples from the ”Treuchtlinger Marmor” formation from
the Molasse Basin (Munich, Germany). All experiments were filmed using a
DSLR camera.
In this study we aim to develop the use of the Particle Image Velocimetry
method to analyze such type of movies. We use the developed Particle Image
Velocimetry method to analyze three of the movies of the preceding study,
which contained samples where the stylolite is at different angles to the
horizontal axis of the sample, so to s3. Two samples has an angle of 90°
between the stylolite and s3 and one with an angle of 40°.
In this open-source software the pixel displacement is analyzed in frames
(i.e. consecutive images, ’before’ and ’after’ image) and it calculates the velocity
distribution within the framepairs, but it is also used to derive, display
and export multiple parameters of the flow pattern. In this study we derived
and displayed the strain rate on the image pairs.
The results show that the strain field of the two limestone samples of a 90°
stylolite behaves identical in the two major stress drops (i.e. DStress) from
the stress-displacement curve. However, the sample with a stylolite of 40° behaves differently. For the two 90° oriented stylolites random extension and
compression takes place at the first highest negative stress drop and symmetric
extension takes place at the second highest negative stress drop from
the stress-displacement curve. However, for the 40° oriented stylolites asymmetric extension takes place at the first highest negative stress drop from
the stress-displacement curve. And random extension at the second drop.
Another result of this study is that the strain rate obtained from PIVlab, the
strain rate per stress drop (MPa) (i.e. in the stress displacement-curve) in
both the two 90 ° stylolite samples and the 40 ° sample were different.
To put this work in the broader context of the energy transition, we consider
the rapid development of the geothermal sector. Nowadays geothermal
energy is considered as one of many alternative sources of energy using
the hot water in the Earth’s surface to generate electricity and power heating/
cooling systems. The Dinantian carbonates in the Netherlands and the
”Treuchtlinger Marmor” carbonates from Germany are of interest for Ultra
Deep Geothermal wells, because of their high geothermal potential. To enhance
the porosity/permeability in a formation where hot water needs to be
extracted hydraulic fracturing can be an option and this study gives insight
about how the rock formations on micro-scale behave when tensile failure
occurs. Tensile is one of the most important properties to be evaluated for
any textile material (i.e. rocks). Tensile failure is important because it occurs
when the stress on a component exceeds the strength of the material thus it
determines the strength of a rock and consequently is influenced by single
plane of weakness such as stylolites.","Micro-Scale analysis; Geothermal Energy; Stylolites; Limestones; permeability; Strain rate; Particle Image Velocimetry (PIV); MATLAB; Strain; Brazilian Disc Test; Tensile strength; Tensile tests; Tensile failure; Displacement; Rock Fractures Behavior","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","","47.768889, 10.140278"
"uuid:a6b4ed98-a46c-4878-9cca-e97dbf753167","http://resolver.tudelft.nl/uuid:a6b4ed98-a46c-4878-9cca-e97dbf753167","Investigation of the Effect of Water Quality on Formation Damage using Porous Discs","de Jonge, Maurits (TU Delft Civil Engineering and Geosciences)","Zitha, Pacelli (mentor); Voskov, Denis (mentor); Gebert, Julia (mentor); Welling, Marco (mentor); Delft University of Technology (degree granting institution)","2020","Water injection is widely used in the petroleum industry for the increase of hydrocarbon recovery or disposal of wastewater. Water production and injection are the primary mechanisms in Geothermal Energy. Both include injecting water into a porous formation under matrix injection conditions. While maintaining water injection is vital in these branches in the industry, so is the occurrence of formation damage (FD) due to suspended contaminants or brine incompatibility. Suspended particles in injection water are retained or deposited due to the creation of an External Filter Cake (EFC) or Internal Filter Cake (IFC) impairing the permeability. Consequently, FD results in Water Injectivity Decline (WID). In most cases, the negative impact on injectivity translates into operational and economic targets not being met. WID, as a result of FD, is highly connected to the Water Quality (WQ) of the injection water. A new approach to water quality (WQ) testing is proposed which suffices as a bridging application of membrane filtration and core flooding. To establish a foundation for this method, tests are conducted by performing particle-laden suspension injection experiments with porous outcrop sandstone 8 mm thin discs utilizing the ‘Con-vergence Hydra’. An experimental study is conducted investigating the effect of water quality (WQ) on formation damage, using dilute (20-100 mg/l) Baracarb2 (CaCO3) particle suspension as a model contaminant. Baracarb2 is tested for particle size distribution, mineral content and stability within synthetic brine (resembling Seawater). Subsequently, suspension flow experiments are conducted on porous thin discs (Bentheimer & Berea sandstone) as well as membrane filters (MF0.45μm). As performing suspension injection test with porous thin disc test utilising the Hydra has not been done before, reproducibility of the experiments is tested. The reproducibility of performing experiments utilising the Hydra is high, with very little difference between the experimental outcomes.Varying WQ within each different porous media type illustrates remarkably similar trends. Moreover, it is demonstrated that by performing a similarity curve collapse, a master curve is obtained for each porous medium type which scales with suspension concentration for Baracarb2. The damage mechanisms explaining this master curve all demonstrate a linear permeability impairment in the early part of the experiments. Subsequently, a linear impedance trend is observed where it is assumed that cake filtration is dominant. The latter is demonstrated by calculating the Modified fouling Index (MFI), which shows a linear dependency with suspension concentration. SEM imaging and Micro-CT scan images substantiate the damage mechanisms hypothesized from the pressure and rate data.The Con-vergence Hydra utilising porous thin discs has great potential for on-site testing which allows fast and reliable results on permeability impairment, i.e. formation damage. Subsequently, monitoring of the water quality can be done by performing MFI analysis during cake filtration. ","Water quality; Formation damage; Con-vergence Hydra; Baracarb2; Calcium carbonate; Porous sandstone disc; MFI","en","master thesis","","","","","","","","2020-06-18","","","","Applied Earth Sciences","",""
"uuid:b0bdbd56-4632-4d77-8b7b-89141992595b","http://resolver.tudelft.nl/uuid:b0bdbd56-4632-4d77-8b7b-89141992595b","3D Geomechanical Model In the Lower Germanic Triassic Group of De Lier Field the Netherlands","Dias Fahmi Fajrin, Dias (TU Delft Civil Engineering and Geosciences)","Bertotti, Giovanni (mentor); Delft University of Technology (degree granting institution)","2020","As the world’s population continues to increase, the demand for energy also increases. However, the use of fossil fuel energy has resulted in disadvantageous impacts for humans and the Earth. This condition becomes a good momentum to find a clean and more sustainable energy resources, given the fact that fossil fuel energy is a non-renewable resource that someday, in the future, its availability becomes scarce. Additionally, environmental awareness concerning energy-mix use and combating climate change also increases globally. Geothermal energy is one of the better alternatives for energy sources, as it is renewable as well as clean and green. A study from the Netherlands Organization for Applied Scientific Research (TNO) says that deeper Triassic sandstones, with possibly higher temperatures, could also potentially contain geothermal reservoirs. Therefore, this condition has paved the way for the exploration of the deep reservoir. The assessment of geothermal production usually faces considerable uncertainty due to, among other things, lack a comprehensive geomechanical model. Therefore, knowledge of the current state of stress is essential to address a wide range of problems that might arise during geothermal exploration and production—those problems such as wellbore stability, fault reactivation, induced seismicity, and deformation in depleting reservoirs. This study aims to construct a 3D geomechanical model in the Lower Germanic Triassic group, in De Lier field. By using the effective stress ratio concept, a 3D geomechanical model is constructed to describe the principal stresses distribution. The principal stresses distribution determines how the faulting stress regime will be formed. The vertical stress, as one of the principal stresses, is controlled by depth and density. On the other hand, the minimum horizontal stress is controlled by Poisson’s ratio. Four models are constructed based on several assumptions. In the model where gravity is the only source of stress, the maximum principal stress σ1 is always vertical. Whereas, in the models where tectonic stress is included, three depth intervals related to the faulting stress regime are observed. Imposing greater tectonic stress to the model will shift the depth of transition downward. Cross-section analysis shows that the local principal stresses variation due to the presence of different stratigraphic units and geological structures (faults and fractures). Fractures and faults at particular depth are inactive under the current stress field. Furthermore, pore pressure and friction coefficient have a significant impact on faults and fractures stability.","stress field; the west Netherlands basin; geothermal; 3D geomechanical model; geology","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:90970051-1c2c-4bfa-8862-051c4cdf3b5a","http://resolver.tudelft.nl/uuid:90970051-1c2c-4bfa-8862-051c4cdf3b5a","Analyzing subsidence in the Netherlands with attribute-enriched InSAR data","Bruna, Marc (TU Delft Civil Engineering and Geosciences)","Hanssen, Ramon (mentor); van Leijen, Freek (graduation committee); van Oosterom, P.J.M. (graduation committee); Delft University of Technology (degree granting institution)","2020","Subsidence is affecting different parts of the Netherlands. The strongest subsidence is observed in the province of Groningen due to ongoing natural gas extraction. Subsidence is also observed at several locations in the province of South Holland, where the processes of peat oxidation, soil compaction and the withdrawal of groundwater are at the root of the problem. In South Limburg, the after-effects of coal mining are seen in the surface deformation, which is characterised by ground heave due to rising mine water, and the potential risks for sinkhole and local subsidence due to near-surface mining. Not only does subsidence cause damage to the natural and built environment, but it also increases the vulnerability towards flooding. Considering the rise in sea level, subsidence forms a pressing issue for low-lying countries, such as the Netherlands. The combined efforts of interferometric synthetic-aperture radar (InSAR) data, global positioning system (GPS) points and gravity measurements have led to the recent Bodemdalingskaart (2018), which represents the nationwide subsidence in three statistically inferred products. These products are the the total surface deformation, the deformation caused by shallow subsurface processes, and the deformation caused by deep subsurface processes. This has triggered the discussion on how the deformation from 'shallow' and 'deep' processes can or should be better understood in a physical sense. The aim of this research is to 'enrich' Sentinel-1 persistent scatterer interferometry (PSI) points with contextual information, or 'attribute-enrichment', in order to better understand the origin of the observed deformation. Classifications from the Dutch 'basisregistraties' (base registries) are assigned to the PSI points, which are stored in a spatial database. The classifications include information on the Dutch soil types and geomorphology. The classifications from Bodemkaart are used in an analysis of nationwide extent, focused on the deformation behaviour of different soils and their groundwater levels. The nationwide average deformation of all track results suggest subsiding trends of about -1.24 mm/yr for marine clay soils and -0.48 mm/yr for peat soils, whereas opposite trends of uplift are observed of, on average, +0.77 mm/yr for river clay soils and +0.54 mm/yr for sand. The soil and geomorphology datasets are also used in combination with the geographic classifications of the built environment to study the distinction between deep and shallow-induced deformation in Groningen and South Holland. Here, the 2 x 2 km grid cell representation of deformation makes it possible to characterise areas with overall low PSI point density. In the localised deformation cases, the behaviour of classes from different attributes can be directly compared, e.g. road polygons intersecting with soil type polygons. For South Limburg, risk-assessment-based classifications are used to enrich the PSI points in the study the coal mining after-effects in the identified risk areas. The risk-deformation results suggest an overall slowing trend in the ground heave of the potential impact areas. The results from the case studies highlight the efficiency of attribute-enriched PSI datasets for the interpretation of deformation, based on both direct and indirect physical classifications.","Subsidence; InSAR; Attributes; GIS; Radar; PS-InSAR; Deformation; Geology; Netherlands","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:b24ad7aa-4eee-4f1f-ad8c-fbdba9df5154","http://resolver.tudelft.nl/uuid:b24ad7aa-4eee-4f1f-ad8c-fbdba9df5154","Geotechnical characterization of sediments from the Rockall Bank Slide Complex","van Opdurp, Dylan (TU Delft Civil Engineering and Geosciences)","Gavin, Kenneth (mentor); Ngan-Tillard, Dominique (graduation committee); Broere, Wout (graduation committee); Lanzafame, Robert (graduation committee); Delft University of Technology (degree granting institution)","2020","The main reason for this research is the possibility of landslides that could trigger a tsunami together with general interest from the oil and gas industry. The goal of this thesis is to find out what the geotechnical properties are of the 7 different locations at the eastern flank of the Rockall bank which is located to the west of Ireland and to the south of Iceland in the Atlantic Ocean. The possible effects of these properties on slope stability are then discussed. This will be done by geotechnically testing the sediments in a laboratory. All standards used during testing can be seen in chapter 3.1.1. The gravity cores used for this research were found to contain parts of sediment that were quite intact together with other more disturbed parts of sediment. The sediments that were found could be classified as silty SAND, clayey SILTS and silty CLAYS which are calcareous to very higly calcareous,from medium to very high plasticity, low to medium-organic and have extremely low to very low undrained shear strengths. Grain size distribtions were found to be gap-graded and well graded and the the sediments were found to be inactive to normal soil based on the Atterberg limits.Geotechnical properties such as gravimetric water contents are found to range from 0.20 to 1.18, the volumetric water contents range from 0.50 to 0.80, a liquidity index from 0 to 3, specific gravities from 2.72 to 2.79, void ratios from 1 to 3, bulk volumetric weights from 14 kN/m3 to 18 kN/m3, dry volumetric weights from 7 kN/m3 to 13 kN/m3, clay contents from 10% to 60%, a silt content of 15% to 60%, a sand content from 8% to 70%, calcite contents from 17.3% to 57.4%, organic matter contents from 2.6% to 9.0%, liquid limits from 0.40 to 0.82 and plastic limits from 0.23 to 0.49. The undrained shear strength for the original and remoulded sediments from the UU DS tests is found to range from 2 kPa to 8 kPa and from 0 kPa to 4 kPa. The undrained shear strengths from original and remoulded sediments from the fall cone test range from 4 kPa to 33 kPa and from 0 kPa to 4 kPa. The undrained shear strengths from the original pocket vane tests range from 5 kPa to 22 kPa. The sensitivities of the sediments measured by the fall cone tests are found to range from 2 to 28 and the sensitivities obtained by direct shear testing are found to range from 0.5 to 4.Based on these undrained shear strengths a failure mechanism similar to that of a direct shear test is found to be more likely on the undisturbed sediments and a failure mechanism like that of a fall cone test is found to be more likely for the remoulded sediments. The non-phyllosilicate minerals that are present are Smectite, Illite, Muscovite, Chlorite and Kaolinite. The phyllosilicate minerals that are present are Quartz, Alkali feldspar, Plagioclase, Calcite, Ankerite, Siderite, Anatase, Rutile, Hematite, Pyrite, Halite and Apatite. This mineral composition can be logically explained by their possible weathering paths and indicates that the possible parent material is Monzogranite type 2 also called Muscovite-metagranite. Magnetic particles are found to be present in all sediments in small amounts that are not quantified. Similar sediments are found to be present from the research of ( Georgiopoulou, Krastel et al., 2019). This confirms the presence of turbidty deposits. These turbidity deposits are indicated to be present at all sites based on the fininng-upward sequences found. Also the presence of lighter interglacial and darker glacial sediments is found. It was also found that the likley reasons for slope instability on the eastern side of the Rockall Bank are the much higher water contents and clay contents of the sediments present compared to the sediments found on eastern side of the Rockall through.The risk of liquefaction upon distrubance is found at sites 1736, 1672, 1988, 1959 and 1604. No risk of liquefaction upon disturbance is found at site 688. The organic matter content is considered to not have an effect on strenght parameters of the sediments present whereas an increase in the amount of foraminifera shells could increase stability of the sediments. Only differential compaction is not found to be a probable factor in lanslide initiation. A long term instability could arise from weathering of Smectite minerals. Erosion could cause slope instability due to sediments with widely varying grain size distributions. The high water content sediments that are present are prone to liquefaction due a disturbance possibly from seismic activity. It is recommended that in future studies a quantification of the marine shell fraction is made. Also a microscope spectrometry is recommended to be done on the sand fraction together with an X-ray diffraction on the <63µm fraction. The most important recommendation is to do a slope stability analysis on the RBSC using the geotechnical properties presented in this thesis.","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:d894ab33-edb2-486c-9379-be4565b53352","http://resolver.tudelft.nl/uuid:d894ab33-edb2-486c-9379-be4565b53352","Modelling direct sediment producers to climate change effects","Burgers, F. (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Remote Sensing)","Browne, N.K. (mentor); O'Leary, M.J. (mentor); Verhagen, A.A. (mentor); Tissier, M.F.S. (mentor); Delft University of Technology (degree granting institution)","2020","The resiliency of coral reef islands to changing environments associated with climate change is controlled by the delicate balance between the import and export of sediment. The majority of the sediment is derived from coral reefs for which the stability of these islands is directly related to reef health. Understanding the sediment signature and its drivers is essential to assess island resiliency. We performed a study on sediments from the islands Eva and Fly in the Exmouth Gulf, Australia. We analysed the grainsize distribution and the abundance of sediment producers in order to desribe and discriminate the spatial distribution of these sediment characteristics and performed statistical analysis to identify corresponding key environmental drivers. We found that the sediments were typically course sand-sized (500 − 1000 [μm]) and the dominant constituent is reef-derived sediment. The median grainsize of Eva island (549 [μm]) is nearly equal to the median grainsize of Fly island (540 [μm]). The standard deviation of the grain size distribution of the sediments from Eva island was much larger than at Fly island. However, analysis of variance showed there were no significant differences between islands (Eva/Fly), hydrodynamic regimes (high/low), distance to shore (inshore/offshore) and local habitat (reef/no reef). Furthermore, a distance-based redundancy analysis showed no key environmental driver responsible for the distribution in grainsize and composition of the sediment. The environmental factors which were analyses were depth, temperature, pH, dissolved oxygen content and the oxidation-reduction potential. The spatiotemporal scales that were studied are potentially smaller than the scales on which climate change effects act, which explains the absence of significant spatial differences or key environmental drivers. Based on these findings it is not possible to assess the resiliency of Eva and Fly islands, however a study from Perry et al. (2011) found that islands with their particular characteristics (sand-sized and coral-dominated) are expected to undergo major morphological change under a range of predicted climate change scenarios. This research provides a baseline for future studies to assess the stability of Eva and Fly islands or sedimentological research other reef-derived islands.","Sediment characteristics; Environmental drivers; Climate change; Morphodynamics","en","student report","","","","","","","","","","","","Applied Earth Sciences","Additional thesis","-21.922153, 114.431844"
"uuid:befd2817-346c-427d-8fc5-2cf77bb10c37","http://resolver.tudelft.nl/uuid:befd2817-346c-427d-8fc5-2cf77bb10c37","Ionospheric errors in GPS: Measuring and modelling the ionospheric delay using single and dual frequency receivers","Beenen, Kathelijne (TU Delft Civil Engineering and Geosciences)","Verhagen, S. (mentor); van de Giesen, Nick (mentor); Delft University of Technology (degree granting institution)","2020","Accurate weather forecasting plays an important role in predicting precipitation events. With the warming climate the precipitable water vapour in the atmospheric is increasing. Since weather parameters as precipitable water vapor have a high spatial variability, interpolation of water vapor data over an area of hundreds of kilometer does not have a sufficient quality for weather prediction applications. Nowadays, researchers are investigating if the precipitable water vapour can be quantified using GPS transmitted signals in a densified GPS network. An accurate quantification of the ionospheric delay is important to efficiently calculate the precipitable water vapour. Moreover, the ionospheric delay is the biggest error and limitation of the GPS signal. It is important to understand how the ionospheric delay varies spatially and in time. Therefore, variability in the ionospheric delay is an interesting factor in weather forecasting and climate change. To monitor the ionospheric delay a high temporal (in minutes) and spatial resolution (in km-grid) is needed, because the ionospheric delay changes spatially and throughout the day. A possibility to achieve this is to densify GPS networks. Previous research has shown that it is possible to measure the ionospheric delay with dual frequency receivers. In developing countries this densification of GPS networks cannot be achieved with expensive dual-frequency receivers. This study investigates if a higher receiver network density can be achieved with the help of low-cost single frequency receivers. Therefore, a densified GPS network of dual and single frequency receivers is set-up in and around Kampala, Uganda. This research demonstrates how the Satellite-specific Epoch-difference Ionospheric Delay model (SEID) can be used to compute the ionospheric delay for a single frequency receiver through time. The SEID model creates a second frequency for a single frequency receiver which is used to resolve the ionospheric delay. The intensity of the ionospheric delay depends on the electrons in the ionosphere. The number of free electrons in the path of a signal is expressed as the total electron content. This research shows how to compute the total electron content in the ionospheric layer of the atmosphere. After computing the second frequency for the single frequency receivers the observations need to be processed using Precise Point Positioning (PPP) to compute the precipitable water vapour. As a case study Uganda is chosen, because it is located on the equator. The ionospheric delay fluctuates more at the equator so this is an interesting region to investigate the variability. The analysis shows that an high accuracy of the GPS signal is needed to create desirable results. Therefore, field campaigns with single frequency and dual frequency receivers should incorporate antennas with noise reduction. In order tot assess the accuracy of the ionospheric delay obtained by using single and dual frequency receivers, future research should be focus on better network set-up and getting the right equipment with better noise reduction","GPS; Single frequency receivers; SEID model; Ionospheric Delay","en","student report","","","","","","","","","","","","Applied Earth Sciences","TWIGA","0.347596, 32.582520"
"uuid:9012d2b1-b2b2-4529-a12b-b118905c2162","http://resolver.tudelft.nl/uuid:9012d2b1-b2b2-4529-a12b-b118905c2162","Improving the quality control of Cofra Roller Compaction: A study on the relation between the impact acceleration and the soil compaction","Kalloe, Davini (TU Delft Civil Engineering and Geosciences)","Pisanò, Federico (mentor); Broere, Wout (graduation committee); Tsouvalas, Apostolos (graduation committee); Vink, Jan-Willem (mentor); Dijkstra, Jeroen (graduation committee); Delft University of Technology (degree granting institution)","2020","Ground improvement in the form of soil compaction plays a important part in reclamation projects. The development of the Cofra Roller Compaction (CRC), a non-circular impact roller, has proven to be valuable in these projects. However, the heterogeneity of the subsoil causes locally a non-uniform degree of compaction. Traditional compaction control tests are limited in measuring depth, expensive and cause time delay. Therefore, the Continuous Compaction Control (CCC) and Continuous Impact Response (CIR)method were developed
in order to provide more real-time information of the compaction based on the response of the drum of the roller. The aim of this study is to develop a semi-empirical energy model which is based on the contact forces of the roller-soil interface as most CCC systems, but also uses field test data as was given in the CIR system to validate this model. The relevant parameters needed for this model were obtained from the field test conducted for the HES Hartel Tank Terminal project in Rotterdam. These included the impact acceleration, the cone resistance, the in situ density, the dynamic modulus and the dynamic plate load test velocity. Two methods are considered in this thesis and both aim to reproduce the measured values from the dynamic plate load test during the field test. The first method considers the acceleration signals and includes double numerical integration of these signals to obtain the displacement, while the other considers modelling the roller as a dynamic plate load test and obtaining the displacement from solving a 2-DOF spring-mass-damper system.
However, after analysis of the motion of the roller, it was observed that due to the non-circular shape of the roller, a wedge effect was created where horizontal shearing forces caused loosening of the soil. This inhibited soil compaction up to 0.5 m depth. The impact acceleration signals were thus not representative of the soil compaction. Nonetheless, the DPL-Soil model was proven to be successful in correlating the soil settlement to the dynamic modulus. This study considers a silty sand, so further research should be carried out to obtain correlations for various soils. In order to develop the semi-empirical energy model, it is thus recommended to capture an accurate acceleration response. This can be done by placing accelerometers at a minimum depth of 0.5 m, replacing the 8G accelerometer with e.g. 16G accelerometer and increasing the sampling rate to at least 1000 Hz. In order to filter out the soil variability, a field test with the roller should be performed on a homogeneous sand without fines. Correlations can then be drawn again for the same field tests performed in this thesis. Finite Element Modelling (FEM) could be used to model the interaction between the non-circular shape of the lobe, the rolling motion and the soil. This might form a better correction method for the acceleration signals than those explained in this thesis. Low frequency geophones can be used to measure the velocity directly. This because low frequency data of the accelerometer should be removed and the roller works on a low frequency. The load imparted to the ground could also be measured directly by burying earth pressure cells at a minimum depth of 0.5m and at various depths to get a more accurate representation of the pressure distribution through the soil layers. By using other numerical integration methods such as Simpson’s 3/8 rule and Boole’s rule, the numerical accuracy of the displacement response of the roller could also be improved.","impact roller; Compaction; acceleration","en","student report","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:387fa42e-7106-4608-91de-137054a566c7","http://resolver.tudelft.nl/uuid:387fa42e-7106-4608-91de-137054a566c7","Hybrid Polymer-based System for EOR at High Salinity and High Temperature: Experiments","Fattah, Abdulaziz (TU Delft Civil Engineering and Geosciences)","Zitha, P.L.J. (mentor); Mirzaie Yegane, M. (mentor); Delft University of Technology (degree granting institution)","2020","Polymer flooding plays an essential role in Enhanced Oil Recovery by means of achieving a more favorable mobility ratio through increasing the viscosity of the displacing phase and thus improve macroscopic sweep efficiency. Conventional polymer, e.g., hydrolyzed polyacrylamide, dissolved in brine at high-salinity and high-temperature can be subjected to thermal degradation due to hydrolysis of amide group to acid which can result in precipitation driven by the interaction between acid groups and divalent ions, so these processes lead to loss in viscosifying power of drive fluid, thereby hindering polymer efficiency. To overcome these challenges associated with polymers at harsh conditions, a new hybrid dispersion consists of silica nanoparticles and hydrophobically modified polyacrylamide was proposed. This study aims to investigate the adsorptive and transport behaviour for this novel combination using rheological measurement and core flood experiments. Two-phase experiments were conducted to reveal the potential ability of the dispersion in increasing oil recovery compared to water flooding. Three different systems are used in this study, first, polymer solution at a concentration of 500 mg/L, second, nanofluids containing only SiO2 particles with a concentration of 5,000 mg/L and the third system is the dispersion of silica nanoparticles at 5,000 mg/L and PAM-98 at 500 mg/L. Rheological tests and single-phase experiment results showed that introducing silica nanoparticles to polymer solution led to the bulk viscosity enhancement and improvement in the adsorptive and transport behaviour of nanofluid. However, two-phase experimental results showed no increase in incremental oil recovery at the given study conditions, since water flooding was highly efficient.","Enhanced oil recovery; Polymer flooding; Nanoparticles; Hydrophobically modified polymer; Adsorption, Injectivity; core flood experiments","en","master thesis","","","","","","","","2022-02-28","","","","Applied Earth Sciences","",""
"uuid:d0c5ccdc-6d02-491a-ae69-87adfef2fa35","http://resolver.tudelft.nl/uuid:d0c5ccdc-6d02-491a-ae69-87adfef2fa35","Rainfall Analysis through GPS SNR data in Uganda and The Netherlands: Additional Thesis","Roosenbrand, Esther (TU Delft Civil Engineering and Geosciences)","van de Giesen, Nick (mentor); Verhagen, S. (mentor); Delft University of Technology (degree granting institution)","2020","Gathering accurate and reliable precipitation data is essential in developing countries, since it applied to a wide range of applications, from improving short term weather models to global climate change research. The most common way of acquiring rainfall measurements is the rain gauge. However, this traditional measurement equipment requires frequent visits from researchers, due to the clogging risks as well as the risk of being easily tampered with by unauthorized people. This makes it impractical and expensive to create a extensive network of these rain gauges, whilst the demand for the precipitating data remains high. A measurement equipment type which is more suitable for this remote and independent requirement for precipitation measurement in developing countries is GPS, since an aspect of GPS measurements is the possibility to use the equipment in relatively remote conditions, with little human interference necessary. In addition to this, due to the nature of GPS measurements, rain is expected to be an important component in GPS data, as a disruptive to the signal, a variable found in the Signal-to-Noise ratio (SNR). Considering the above, GPS seems like a good alternative to the traditional rain gauge for precipitationmeasurements. During this additional thesis, the question whether GPS can be used reliably for precipitation data, will be answered. During a measuring campaign in Uganda from September to November in 2018, GPS data was gathered near precipitation measurement locations from TWIGA’s School-2-School initiative. For the processing, graphs of the SNR and precipitation of the same days and locations were created and were visually inspected to see if a relationship or correlation was present. From these graphs this relationship between SNR and precipitation was not immediately clear. The nature of the SNR can be caused by a multitude of reasons and variables and unless the correlation is very strong between variables, this correlation will not be very clear from just a visual inspection of these SNR and precipitation graphs. To untangle these variables, correlationmatrices were used, where the variables can be looked at in pairs and instead of as quadruplets (or more). From the correlation matrix of the Ugandan data is is clear that correlation between precipitation and SNR is not significant, as it is similar to the correlation with a randomly generated variable. A slight correlation is present, however, with the GPS elevation angle. During processing, data from Cabauw (the Netherlands) was used as an extra data set to compensate for the small amount of rain in the Ugandan data. This processing followed the same procedure as was applied with the Ugandan data; visual inspection of the SNR and precipitation graphs and generating a correlationmatrix. In the Dutch data the relationship between the SNR and the precipitation was still small, however, larger than in the Ugandan data. Nonetheless, the correlation between the SNR and the elevation was very strong. In conclusion, from both the Ugandan and Dutch data, the correlation between precipitation and SNR is not strong enough, or in other words, using GPS data to approximate rainfall, is not achievable using the methods applied and resources used during this additional thesis.","","en","student report","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:7620e531-6bf7-4d7f-9f53-aea392fb05f0","http://resolver.tudelft.nl/uuid:7620e531-6bf7-4d7f-9f53-aea392fb05f0","Quality assessment and quality control system for armourstones; by the use of simple testing tools","Spoelstra, Jelle (TU Delft Civil Engineering and Geosciences; TU Delft Geo-engineering)","Ngan-Tillard, Dominique (mentor); Dieudonné, Anne-Catherine (graduation committee); Verhoef, Peter (graduation committee); Abels, Hemmo (graduation committee); Delft University of Technology (degree granting institution)","2020","Several waterway protection structures in the Netherlands dealt with rapid degrading armourstone after construction. This suggests that the current selection procedure of armourstones is not flawless to all degradation mechanisms, especially in dynamic environments. In this work armourstone is meant to include all rock that is used in river, coastal and offshore constructions, including rip rap and rock fill. Armourstones are in the Netherlands selected by their CE marking, which lists the description of the armourstone product and information on regulated characteristics. These characteristics are tested according to the European standard EN 13381-1&2:2002, which specifies the properties of aggregate acquired by processing natural materials for use as armourstone. This research is executed to provide a contribution in the quality control and assessment of armourstone and rock fill to ensure proper handling and installation in coastal and waterway protection structures. The research started with a durability investigation according to the standard EN 133831&2:2002 on sampled sandstones and limestones that will be used in a submarine trench backfill, to check the regulated armourstone characteristics. Next, a petrographic analysis under the microscope was performed on methylene blue (MB) stained thin rock sections to investigate the presence of deleterious constituents and structures. This analysis was followed by extensive index testing to investigate the applicability of simple testing tools in a durability investigation. These tools include the Brazilian tensile strength (BTS) test, an indirect tensile strength test, the Equotip test, a surface hardness tester that records the surface rebound of an impact body, and the MB adsorption and staining test. MB is a dye that colours constituents with an excess in negative electric charges. The tests according to EN 13383-1&2:2002 suggested that the sampled armourstone bulk satisfies the required durability parameters and no evidence was found that indicates rapid degradation during the engineering lifetime. Nevertheless, variability in the armourstone pieces was spotted and some individual rock pieces approached or exceeded minimum durability requirements. The BTS test revealed considerable variation in tensile strength, a key parameter to assess degradation, between armourstone blocks and within a single block when a similar orientation of the bedding was maintained. Moreover, the orientation of the bedding in the sandstone had large influence on the tensile strength, where the values obtained perpendicular on the bedding were twice as high than parallel to the bedding. Single impact method (SIM) Equotip measurements on rough, untreated aggregate surfaces were consistent. The rebounds correlated to visual features like grain size, cracks, surface roughness and degree of weathering within handheld specimens. Equotip measurements on the rock cores and sawn surfaces obtained higher mean rebound values and smaller standard deviations. The mean and standard deviation are considered most suitable to be used in a durability investigation. The repeated impact method (RIM) by the Equotip was not successful to indicate the degree of weathering of single hand specimens. The mean Equotip values on the aggregate correlated well to the water absorption when divided into proper density and size classes. The mean rebounds on the cores distinguished well between weathered and intact cores when saturated, and correlate well to the unconfined compressive strength (UCS) values. Furthermore, the Equotip mean rebound value related to the BTS value when performed on isotropic rock disks. The MB adsorption test and MB staining of the thin sections indicated the presence of localised spots and laminae rich in clay or organic matter. The staining of sawn aggregate surfaces agreed with some of the deleterious structures in the thin sections, yet was not consistent throughout the tested rock pieces and varied between the dark coloured limestone and light coloured sandstone. The Equotip test, BTS test and MB adsorption test are quick, easy and cheap methods to obtain more understanding in variability and rock behaviour which are not necessarily captured by the standard laboratory tests according to EN 13383-1&2:2002. The simple index tests should always be accompanied by the standard laboratory tests to provide a proper reference and understanding. Detailed mechanical durability tests, like the slaking test or wet-dry cyclic tests, should be performed when the durability assessment indicates a high amount of deleterious minerals and structures, to identify the amount of degradation caused by swelling behaviour of these minerals.","Armourstone; Rock Durability; Equotip; Simple Testing Tools","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:bcadae15-3429-443f-8421-3aa661d8495b","http://resolver.tudelft.nl/uuid:bcadae15-3429-443f-8421-3aa661d8495b","Chalk putty: specimen preparation and aging properties","Sanchez Alonso, Carlota (TU Delft Civil Engineering and Geosciences; TU Delft Geo-engineering)","Ngan-Tillard, Dominique (mentor); Jommi, Cristina (graduation committee); Zitha, Pacelli (graduation committee); Delft University of Technology (degree granting institution)","2019","Chalk putty is a soil-like material that is formed when intact chalk is disturbed. Recently, it has become of special interest due to the development of offshore wind farms in the North and Baltic Seas, where in a number of sites piles are driven into chalk strata. Several pile tests reported in the literature show increased shaft capacity up to 4 months after driving. Although it is a widespread remark in the scientific publications that chalk properties improve over time, laboratory replications of this phenomenon are scarce and the results are inconclusive. The aim of this thesis is to develop a specimen preparation technique yielding representative specimens as well as feasible for commercial purposes. Thereafter, the evolution of the characteristics of chalk putty over time is assessed through laboratory tests. Triaxial with Bender Elements, Direct Simple Shear, Constant Rate of Strain and Thixotropy have been conducted on specimens aged up to 3 months. Finding that the behavior of chalk putty cannot be classified among the classic types of soils. On one hand, Constant Rate of Strain tests have shown that the response is comparable to silty soil, with a gradual transition between re-loading and virgin compression lines, leading to difficulty in the determination of the yield point. On the other hand, in shear, the critical state friction angle is in the range of dense sand. Regarding the volumetric response, there is an initial compressive response, succeeded by a constant volume phase during destructuration and eventual dilation or contraction at larger strains. Furthermore, it was determined that the material possesses thixotropic properties when mixed with de-ionized water. Finally, no increase in the shear strength or was recorded while the initial shear stiffness decreases with aging time -due to unconfined preservation of the samples. However, the ultimate dilatancy of the specimens increases over time, this may be a result of dissolved calcium carbonate during crushing and saturation which re-precipitates or re-cements around the grains.","Chalk; Ageing; Sample preparation; Soil laboratory testing","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:75210d94-22f5-4f99-9327-c65044543b3e","http://resolver.tudelft.nl/uuid:75210d94-22f5-4f99-9327-c65044543b3e","Design of a Miniature Cone Penetrometer: Design and Calibration of a Miniature Cone Penetration Test Device for the Geo-Technical Centrifuge of Delft University of Technology","Honardar, Siavash (TU Delft Civil Engineering and Geosciences)","Askarinejad, Amin (mentor); de Lange, Dirk (mentor); Delft University of Technology (degree granting institution)","2019","The aim of this project is to elaborate upon the design proposal of a miniature cone penetration test device. The usage of CPTs in the geotechnical centrifuges has proven to be a reliable experimental method. The usage of a CPT in a centrifuge can provide determinant results for many applications of geotechnical experimentation. The usage of cone penetration tests in centrifuge modelling is a significant experimental method in geotechnical engineering. The measurement of cone resistance and pore-pressure during in-flight tests can provide valuable data to correlate with soil properties and material behaviour. Through the years, this method has proven to be reliable and repeatable and has helped in verifying correlations of laboratory measurements and field data. The inexpensive and time-efficient nature of centrifuge testing and the reliability of cone penetration testing complement each other. This method has many relevant applications and acts as an effective tool. A literature study is conducted to obtain practical information on the design process of minia- ture CPTs. The existing designs are studied and their specifics are compared to the boundary conditions of the centrifuge of Delft University of Technology. This apparatus is capable of con- ducting tests at 300 times the gravitational acceleration and can carry samples with widths up to 400 millimeters. Two sets of existing sample containers are considered in this project which define physical dimensional boundaries. These sample containers consist of rectangular and cylindrical boxes with defined dimensions. The existing boundaries are further analyzed with respect to boundary effects derived from previously conducted tests to define design specifications for a potential miniature probe. The definition of such boundaries set the basis of the design proposal. For the rectangular containers a miniature probe with a maximum diameter of 4 millimeters can be used. As for the cylindrical sample containers, miniature probes with maximum diameters of 7.5 and 9.5 millimeters are appropriate to be designed. The analyzed existing designs are then scaled and altered with respect to the determined boundary values and the proposal is further evaluated.
Three miniature CPTs are designed with diameters of 4, 7.5 and 9.5 millimeters. Each design has certain applications and can be used in specific scenarios. All three designs include modular load cells and sub-parts that can be replaced and altered. Each proposed device consists of a modular load cell designed based on required material properties to experience a minimum amount of 500 micro-strain without buckling. The first design, with a cone diameter of 4 millimeters, can be used in any container with a minimum width of 12 centimeters and for soil samples with a maximum average grain size of 200 micrometers. The second design, with a cone diameter of 7.5 millimeters, can be used in containers with a minimum width of 22.5 centimeters and is applicable to soil samples with a maximum average grain size of 270 micrometers. The final design, with a diameter of 9.5 millimeters, is meant to be used in sample containers of widths above 28.5 centimeters and for soil samples with a maximum average grain size of 340 micrometers. The designs are then evaluated with regards to manufacturing costs and feasibility. An estimation is made based on previously designed and patented devices and material catalogues provided by manufacturers. The cost of the first two designs are estimated to amount to 1580 to 2080 Euros, whereas the third design is estimated to cost 3080 to 3580 euros due to temperature compensated pore-pressure sensor that is included in the design. Upon further evaluation, the first design with a diameter of 4 millimeters is chosen as the most feasible and practical concept due to applicability and practicality of the design.","Cone Penetration Test; CPT; Centrifuge modelling; Design Proposal","en","student report","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:5a9ce853-6d01-4643-8406-704faf5c34f2","http://resolver.tudelft.nl/uuid:5a9ce853-6d01-4643-8406-704faf5c34f2","Evaluating the electrochemical properties and behaviour of copper/cobalt minerals: Using Cyclic Voltammetry and Electrochemical Quartz Crystal Microbalance techniques","Elpenhof, Chris (TU Delft Civil Engineering and Geosciences)","Buxton, M.W.N. (mentor); Glass, Hylke J. (graduation committee); Bakker, M.C.M. (graduation committee); Delft University of Technology (degree granting institution)","2019","Mining projects around the world face a significant challenge to reduce their footprint and be more environmentally friendly. Research has shown that mineral processing is of major influence, due to the use of heavy chemicals that are both expensive and polluting. Currently, electrowinning (the electrodeposition of metals) is only used in the last purification step of the process. So far, the majority of the studies on cobalt have focused on non-electrowinning possibilities. Therefore, it is of interest to investigate the electrochemical behaviour within different environments to obtain more information and gain a better understanding. This thesis focuses on the electrochemical behaviour and deposition of cobalt-bearing minerals, which will be evaluated with the help of cyclic voltammetry (CV) and the electrochemical quartz crystal microbalance (EQCM). These techniques use the help of multiple variable input parameters, which will be investigated and compared to gain the optimised condition to perform the experiments. Furthermore, the sensitivity of the techniques to different input parameters and different solutions will be investigated. This is done to investigate what the origins are for the differences in the electrochemical behaviour of copper-cobalt minerals in aqueous solutions using analytical, synthetic and real ores, and to find a correlation between the obtained results using the graphs generated using CV and EQCM-techniques. This is done to investigate to possibilities using selective electrowinning, meaning the electrodeposition of multiple elements within the same electrolyte solution. Based on a review of the literature, the experimental setup used for the experiments will be discussed to gain better understanding of the specialised equipment and corresponding software. Cobalt chloride, cobalt sulphate and copper sulfate solution will be evaluated first, after which two synthetic cobalt-bearing minerals containing iron will be tested. With the help of CV, the electrochemical behaviour, e.g. redox- reactions, can be analysed. Using the EQCM, accurate measurements of the mass change per unit area of the electroplated cobalt will be recorded. Synthetic minerals will be used to discover how much can be recovered using this technique. Finally, six samples from the Democratic Republic of Congo (DRC) will be evaluated to obtain the same data as for the synthetic minerals. For this QEMSCAN data is used to evaluate the mineral composition. Analysis of the results demonstrated that under different circumstances in different environments, similar electrochemical behaviour and the occurrence of copper, iron and/or cobalt deposition is observed. However, for special cases these reactions do not occur. This difference can be explained by a varying mineralogy, where bornite and chalcopyrite have a positive effect on the electrochemical activity. Regarding the shape of the voltammogram, the number of electrons involved in the reaction has the largest influence. Furthermore, alkaline conditions have a positive effect on the electrodeposition of cobalt. No overall correlation has been found between the samples. For all experiments similar reactions and electrochemical activity is observed regarding the peak potentials and within the same environment, correlations can be found. Recommendations for further research are to investigate the influence of changes to parameters such as temperature, magnetic field and impurities on the electrochemical behaviour of the reaction and changes in the yield of electrodeposited material, to generate more data to validate and calibrate the characteristic potentials that can be used for selective electrowinning and to gather more data of the selective electrowinning experiments in terms of additional (rare) elements, such as lithium.","Electrochemistry; Cobalt; Copper; Cyclic voltammetry; Electrochemical quartz crystal microbalance; CoG3-project","en","master thesis","","","","","","","","2020-03-09","","","","Applied Earth Sciences","Cobalt: Geology, Geomicrobiology and Geometallurgy",""
"uuid:d23fc690-0590-4fec-bd7a-dc259eafc4c8","http://resolver.tudelft.nl/uuid:d23fc690-0590-4fec-bd7a-dc259eafc4c8","SAR-based flood mapping in urban environments","van der Zee, Thijs (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Remote Sensing)","van Leijen, Freek (mentor); Hanssen, Ramon (graduation committee); ten Veldhuis, M.C. (graduation committee); Delft University of Technology (degree granting institution)","2019","Flooding is a very costly natural disaster especially when it hits urban areas. Yet synthetic aperture radar (SAR) based flood mapping barely works in urban areas. Buildings and man made objects have similar backscatter signatures as still standing water. This makes them hard to distinguish from one another. Structures can block the visibility of the ground surface for side looking SAR satellites making large parts of potentially flooded ground going unseen by SAR satellites. Smooth surfaces and limited ground visibility make it hard to produce accurate flood maps using SAR in urban environments. Here we have shown how the use of a temporal stack can improve the result of urban flood detection with
SAR. Traditionally SAR based flood mapping uses a single image or an image pair to classify flooded and non-flooded pixels. This study found these methods unable to detect flooded pixels in an urban setting. By using a temporal stack of SAR images more pixels are correctly classified as flooded while keeping false positive classifications low. However the number off correctly classified pixels remains too low to be useful on its own, by adding ancillary data in the form of a high resolution DEM an accurate flood map for a very specific area is produced. This means that SAR images are not suitable for flood mapping in urban areas as a single source of information. When they are combined with other data they have the potential to produce accurate flood maps useful for First responders when the next flooding disaster hits.","SAR; Flood; mapping","en","master thesis","","","","","","","","2019-10-07","","","","Applied Earth Sciences","",""
"uuid:6725a374-c44f-402f-8d10-ac63827c3773","http://resolver.tudelft.nl/uuid:6725a374-c44f-402f-8d10-ac63827c3773","Determining the structural evolution and strain distribution of a geologically complex area in SE of France by restoring multiphase deformation","Jones, Cyrille (TU Delft Civil Engineering and Geosciences)","Blom, J.C. (mentor); Abels, H.A. (graduation committee); Delft University of Technology (degree granting institution)","2019","The structural evolution, phases and amount of deformation, and the strain distribution of the sedimentary cover of a geologically complex area of 270 km2 in the French subalpine chains (Southeast of France; in the surroundings of the village La Motte-Chalancon) were deduced from the modelling of two folded and faulted competent layers (Tithonian and Barremian formations) both in 2D and 3D. These models were constructed from collected geological data such as BRGM (Bureau de Recherches Geologiques et Minères) geological maps, previous Bachelor’s fieldwork data, new field data and the study of aerial photographs (Google Earth). A grid of 20 vertical 2D cross-sections (10 N-S, and 10 E-W) was generated which was then imported and digitized in the geological modelling software package Move and the 3D model of the competent layers was built, validated and restored to its initial configuration prior to deformation by first removing each fault displacement (Fault Parallel Flow method) and then unfolding each structure (Flexural Slip method) in Move, showing deformation and shortening in two directions: N-S and E-W. The amount of deformation in both directions was estimated from the 3D model. Major deformation took place in the N-S direction with a maximum of 21% shortening for both layers which corresponds to an absolute shortening of 4067m for the Tithonian layer and 4076m for the Barremian layer. Less deformation took place in the E-W direction with a maximum of 9% to 10% for the Tithonian and Barremian horizons respectively which corresponds to an absolute shortening of 1697m and 1976m respectively. This resulted in an area reduction of 16% and 19% of the original area prior to deformation for the Tithonian and Barremian, respectively.
Two phases of deformation over geological time were deduced from the orientations of the folds and faults present in the studied area. The presence of NW-SE trending folds and thrust faults (e.g. Mt D’Angele fault, Pommerol fault, or Chalancon fault) along with a conjugate strike-slip system (of one oriented N-S and one NE-SW) reflects the NE-SW compressional stress regime of the first stage of deformation which is related to the Pyrenean phase of the Alpine Orogeny. The second stage, the Alpine phase, which resulted in E-W contractions, is associated with the formation of domal/basinal structures as well as folds with plunging fold axes within the studied area. The northeastern part of the studied area exhibits different fault trends. Two tear faults (L’Aiguille and Ruelles fault), a dextral N-S strike-slip fault (Establet fault), and two E-W trending reverse faults (Peyssias and Hidden fault) resulted from N-S compression. These are related to the first phase of the Pyrenean stage, and then later partly rotated during the latter phase of the Alpine stage.
The strain maps produced from the 3D model displaying the high-/low-strain zones of the area mainly show E-W and NW-SE trending strain zones which confirm the direction of the main stress regime of the Pyrenean compressional phase oriented NW-SE.
surface melt on blue ice. This is done via interferometry (and the corresponding coherence) and with the backscatter coefficient. Coherence turns out the be an unreliable method to detect surface melt, since the influence of wind and precipitation on the decrease of coherence is dominant. Thus, surface melt detection via this method is difficult. Backscatter showed some potential to detect surface melt on blue ice, but due to the larger standard deviation than the actual decrease of backscatter (assumed due to surface melt), a clear distinction between blue ice and surface melt can not be made. Melt features, such as rivers, lakes and ponds are detectable with the backscatter, due to their distinctive shape. Since these melt features are linked to surface melt, backscatter can indirectly be used to detect surface melt on blue ice.","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:40c078cd-f3fe-4625-896e-ac981f3158fc","http://resolver.tudelft.nl/uuid:40c078cd-f3fe-4625-896e-ac981f3158fc","Geotechnical Hazards | Geological Considerations in Dams Failure","Bărbunţoiu, Teodora (TU Delft Civil Engineering and Geosciences)","Ngan-Tillard, Dominique (graduation committee); Broere, Wout (mentor); Delft University of Technology (degree granting institution)","2019","Dams and reservoirs pose safety concerns to society worldwide. In case of a disaster, the water impounded in the reservoir escapes and destroys everything in its path. Reasons for failure range from geology, hydrology and seismicity, to design problems, lack of maintenance and poor field investigation. Prior cases show that various dams gave away mainly due to geological causes, so there is a particular interest to see how the local terrain features could influence the longevity of the structure. Three historical case studies are discussed in order to emphasize the impact of geology regarding dam failure. The Saint Francis Dam is a prime example of poor site investigation, where the lack of knowledge on the foundation rock led to the rupture of the gravity dam. The Malpasset Dam gave away predominantly due to underestimated effects of the uplift, nevertheless, the geologists were unaware of an active fault system and the mechanical properties of the rock mass. The Baldwin Hills Reservoir comes with a more thorough site investigation, yet still, due to earth movements, the water from the reservoir infiltrated through the embankment. Therefore, geological features at the site need to be included in the design options of the dam in order to ensure a safe, feasible and economical project. With respect to the way we build nowadays, engineers have learnt important lessons from past experiences, however, issues such as ageing of the structures and the unpredictability of geology and weather, could still influence the safety of modern dams.","","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:2b3bf137-051e-4141-8d22-573d32e640fc","http://resolver.tudelft.nl/uuid:2b3bf137-051e-4141-8d22-573d32e640fc","Interaction between tensile fractures under varying orientations in Indiana Limestone","ter Steege, Friso (TU Delft Civil Engineering and Geosciences)","Barnhoorn, A. (mentor); Pluymakers, A.M.H. (graduation committee); Ngan-Tillard, D.J.M. (graduation committee); Delft University of Technology (degree granting institution)","2019","The interaction between fractures and the associated effects are studied in fields like geothermal engineering, seismology, volcanology and geo-engineering. Fractures can massively influence the permeability and porosity in a rock formation, reducing resistance to flow. However, to improve permeability, multiple fractures must connect to each other. Therefore, it is important to understand the effects of a stress field under varying orientations and how it influences new and existing fractures. Brazilian disc tests were filmed and performed on 18 Indiana limestone samples, after which 13 samples were fractured a second time under orientations varying from 20° to 90°. Afterwards, video footage of the tests was used to study fracture propagation and fracture roughness. Analysis of the results showed that four distinct types of fracture behaviour occurred. Each type was generally displayed between certain angles. Case 1, under 30° shows reactivation of the original fracture. Case 2, between 30 and 45°, shows largely reactivation of the primary fracture but new secondary fractures towards the ends of the sample. Case 3, between 45 and 60°, shows the primary fracture closing and formation of secondary fractures near the centre of the disk. Case 4, from 60° onwards, shows the primary fracture close completely while a new fracture forms perpendicular and independent of the first. The results imply that initiating a stress field in a certain orientation has differing consequences. A stress field more parallel towards the original fracture causes reactivation of the fracture, without much impact on the permeability. However, a stress field initiated perpendicular to the primary fracture causes a new fracture to form, independent of and straight through the primary fracture. This is likely to increase permeability and therefore reduce resistance to flow.","Brazilian Disc Test; indiana limestone; tensile fractures; fracture interaction","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:ef4fd272-72e8-466d-8674-d0b2b27829d0","http://resolver.tudelft.nl/uuid:ef4fd272-72e8-466d-8674-d0b2b27829d0","ERT and GPR as Potential Geophysical Tools for Detecting Clandestine Buried Forensic Evidence","Mulder, Claire (TU Delft Civil Engineering and Geosciences)","Slob, E.C. (mentor); Drijkoningen, G.G. (mentor); Nienaber, Coen (mentor); Delft University of Technology (degree granting institution)","2019","Forensic investigations focused on determining clandestine buried weapons, narcotics or even homicide evidence, can be expensive, inefficient and depend greatly on prior information and the tools available. Geophysical tools have potential to improve these investigations, on the ground that they can detect shallow buried objects in a non-invasive way. This report studies the use of electrical resistivity tomography (ERT) in combination with ground penetrating radar (GPR) to detect buried objects at two different sites, both with conditions found here in The Netherlands. The first is a test site at the Technical University of Delft, The Netherlands. Here, two plastic barrels are buried, one is empty and the other is filled with metal rods. The second site is at the ARISTA Facility in Amsterdam, The Netherlands. Here, human cadavers are buried for forensic research. The ERT was used in two ways, the first was to produce 2 dimensional (2D) surveys, which were combined to create a 3 dimensional (3D) model. The second method made measurements that created a 3D model directly. For each the dipole-dipole array was used. At the TU Delft site the results for the 2D method showed clear resistivity anomalies at the locations of the barrels. These anomalies corresponded to clear reflections in the GPR radargrams. The results at the ARISTA facility are inconclusive due to damage in the instrument used. The grid designs made for both ERT methods could however be used in a continuation of this study, and future research should be done within this topic to improve forensic investigations.","","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:bfc71739-37d1-45d1-b9f7-e87448626fa6","http://resolver.tudelft.nl/uuid:bfc71739-37d1-45d1-b9f7-e87448626fa6","Determination of REV and Effective Properties of Fluvial Depositional Systems: A feasibility study using 3D FLUMY models","Lottman, Tim (TU Delft Civil Engineering and Geosciences)","Storms, Joep (mentor); Martinius, Allard (mentor); Delft University of Technology (degree granting institution)","2019","Fluvial reservoirs are difficult to model due to the high permeability contrast between the sandstone bodies and the overbank deposits and the complex geometry of the permeable (sandstone bodies) and impermeable zones (overbank deposits). A set of fluvial meandering models has been generated using FLUMY. The models represent a range of Net-to-Gross ratios and sandstone body geometries. In order to quantify the effect of sample size on effective properties, the models are evaluated based on the statistical moments of the probability distributions of porosity and single-phase permeability as a function of sample size. The porosity and permeability show a high spread at small sample volumes, but the spread reduces as the sample size increases. A normalized standard deviation, the coefficient of variation, has been used as a criterion for the variability of the probability distributions. The coefficient of variation of the porosity and the horizontal permeability show a monotonic decline as a function of sample size. The coefficient of variation of the vertical permeability does not show a monotonic decline. This is caused by a drastic decrease of the mean of the vertical permeability with increasing sample volume. The mean of the horizontal permeability also decreases with increasing sample size, but to a lesser extent. The mean of the probability distributions of permeability as a function of sample size converges much earlier than the standard deviation. This convergence indicates that we can determine the effective properties at the Representative Elementary Volume (REV), without reaching REV. The convergence of the mean could potentially be used as a criterion for the relevant spatial scale of upscaling from the fine scale static model to the coarse scale model. Furthermore, if cells are uncorrelated at a scale where the mean of the permeability is not a function of sample volume anymore, random attribution of properties can be used to populate dynamic grid cells.","Representative Elementary Volume; effective properties; permeability; porosity; fluvial deposits; FLUMY; connectivity; Sandstone; claystone; geometry","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:fc61066f-7acc-49a8-8ceb-6223ce90c063","http://resolver.tudelft.nl/uuid:fc61066f-7acc-49a8-8ceb-6223ce90c063","Estimation of wintertime Arctic sea ice thickness with satellite scatterometers","Egbers, Ruben (TU Delft Civil Engineering and Geosciences)","Belmonte Rivas, Maria (mentor); Lhermitte, S.L.M. (graduation committee); Slobbe, D.C. (graduation committee); Hanssen, R.F. (graduation committee); Delft University of Technology (degree granting institution)","2019","Accurate information on Arctic sea ice thickness has been historically limited both spatially and temporally to spare submarine sonar measurements until the advent of satellite altimeters such as ICEsat (operating from 2002 to 2008) and CryoSat-2 (operating from 2011 to present day). This study aims to use the historical record of normalized radar backscatter measurements from satellite Ku-band and C-band scatterometers (ERS, QuikSCAT and ASCAT), which have been continuously operating since 1992, to homogenize the satellite altimeter record and extend the record of Arctic sea ice thickness measurements backwards in time. This study is structured so as to first derive a set of empirical relationships between normalized backscatter measurements and wintertime sea ice thickness estimates in the Arctic using existing satellite altimeter records as a reference. Two separate scatterometer sea ice thickness models are produced using coincident scatterometer and altimeter observations, one for C-band sea ice thickness estimation using ASCAT and CryoSat-2 collocations, and another for Ku-band sea ice thickness estimation using QuikSCAT and ICESat collocations. Based on the agreement to the altimeter records, the estimation of wintertime sea ice thickness using the C-band and Ku-band scatterometer models is uncertain to within 0.5 m (1-sigma), that is, a precision similar to that of the original altimeter references. The homogenization of the satellite altimeter records cannot be done directly, because the ICESat and CryoSat-2 instruments operate in different periods, but it can be done indirectly by comparing the sea ice thickness estimates obtained from Ku-band (based on ICESat) and C-band (based on CryoSat-2) estimates during the years that the Ku-band and C-band scatterometers operate simultaneously. These overlap years have been used to verify the consistency between the C-band and Ku-band relationships, and to correct for a 0.55 m bias in the CryoSat-2 reference, having considered the earlier ICESat record as absolute standard. After removing this bias from the CryoSat-2 reference, the sea ice thickness estimates from C-band and Ku-band records agree to within 0.15 m (1-sigma). Moreover, the resulting scatterometer sea ice thickness models allow the introduction of new thickness thresholds from a previously existing backscatter-based classification of Arctic sea ice types, providing a thickness threshold of 1.54 m to define first year ice (FYI), and a thickness threshold of 2.25 m to separate second year ice (SYI) from older multiyear ice (old MYI). Ancillary datasets were used to investigate the correlations between backscatter-based sea ice thickness and physical variables, such as snow depth and surface deformation, in order to investigate possible sources of systematic error, which otherwise appear to be bound within 0.30 m (1-sigma). The maps of differences between scatterometer and altimeter sea ice thickness estimates were analysed in terms of collocated sea ice convergence, sea ice shear and snow depth parameters using a multiple regression model. The results show that both the Ku-band and C-band models underestimate ice thickness in areas of high convergence such as the Fram Strait, and overestimate ice thickness in areas with high shear such as the Beaufort Gyre. These correlations may be interpreted as led by increases in backscatter due to surface deformation with (case of convergence) or without (case of shear) associated increases in ice thickness. In addition, the Ku-band model is found sensitive to snow load, with overestimation interpreted as led by an increase in backscatter without associated ice growth, and the C-band model is sensitive to marginal rough ice. An unphysically large dependence on snow depth was found for the C-band estimate, which we conjecture is due to problems with the CryoSat-2 reference. Finally, a reconstruction of Arctic sea ice thickness in the wintertime has been made by combining the Ku-band and C-band sea ice thickness models with the normalized radar backscatter record of ERS, QuikSCAT and ASCAT from 1992 through 2017. These showed a decline average Arctic sea ice thickness of -0.28 m / decade, with a steady decline in second-year ice and high variability in the mean multi-year ice thickness.","Arctic; sea ice thickness; scatterometers; ERS; ASCAT; QuikSCAT; estimation; ICESat; CryoSat-2","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:d25e499e-89de-4fa5-b96e-3ada53141754","http://resolver.tudelft.nl/uuid:d25e499e-89de-4fa5-b96e-3ada53141754","Optimization of Jetted Radial Wells","Troost, Diederik (TU Delft Civil Engineering and Geosciences)","Jansen, J.D. (mentor); Peters, Lies (mentor); Leeuwenburgh, O. (mentor); Delft University of Technology (degree granting institution)","2019","Jetted radial wells are a relatively new form of hydraulic stimulation for oil and gas wells, where small diameters holes extend radially from a wellbore. This technique for increasing well connectivity could also be applied to geothermal wells. Radials can be freely placed along a backbone well, making the design of an economically viable well plan time intensive. Numerical optimization has been extensively applied to well design and will be applied for the design of a radial well plan. A simple optimization case is used to compare gradient-based and gradient-free optimization for jetted radial optimization, the gradient-free CMA-ES algorithm is chosen for the workflow. In addition to CMA-ES, mixed integer CMA-ES and uncertainty-handling CMA-ES are incorporated in the workflow. Three reservoir cases are evaluated for optimization using these algorithms. The workflow is able to determine well plans with higher NPV in each of these cases though finding a global optimum remains difficult.","Petroleum Engineering; geothermal; Optimization; Jetted radial wells; CMA-ES","en","master thesis","","","","","","","","2019-01-09","","","","Applied Earth Sciences","",""
"uuid:64b67a50-3fcb-4b7f-82e1-56c040170262","http://resolver.tudelft.nl/uuid:64b67a50-3fcb-4b7f-82e1-56c040170262","The suitability of High Temperature – Aquifer Thermal Energy Storage in Holland-Rijnland","de Voogd, Rein (TU Delft Civil Engineering and Geosciences)","Bloemendal, Martin (mentor); Vardon, Phil (mentor); Delft University of Technology (degree granting institution)","2019","High Temperature – Aquifer Thermal Energy Storage (HT-ATES) is a way to efficiently store heat with use of the subsurface. Region Holland-Rijnland has the vision to be free of the use of natural gas in 2050. A proposed high temperature heating network from the port of Rotterdam to the households of Leiden, combined with the use of an HT-ATES system as a buffer, could be the next step to achieve the laid-out vision. This research is a first step in the possibility of placing an HT-ATES system near Leiden. An interpretation of the subsurface near Leiden is done based on information from DINOloket to find potential formations and aquifers. Then, combined with different scenarios for the heat demand from the proposed heat network, a preliminary design of an HT-ATES system is made to test the viability of the potential aquifers. The most suitable aquifer is found in the Maassluis formation at a depth of 230 meters. Per scenario, this aquifer needs the least number of wells for the desired pumping rate. Depending on the scenario, the aquifer has a thermal recovery efficiency ratio between 0,16 – 0,26 and an area – to – volume ratio between 0,051 – 0,056. Other suitable aquifers can be found in the Maassluis formation at a depth of 170 meters and in the Oosterhout formation at a depth of 320 meters. The subsurface near Leiden is suitable for an HT-ATES system, but more research needs to be done on the conflict between heat supply from the port of Rotterdam and heat demand from the proposed network in order for an HT-ATES system to fully supply the seasonal heat demands.","HT-ATES; High temperature storage; ATES","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:3ca2d0d4-d275-46fd-b8db-3f66ebef53a2","http://resolver.tudelft.nl/uuid:3ca2d0d4-d275-46fd-b8db-3f66ebef53a2","Discrete Frequency Seismology","Visser, Adriaan (TU Delft Applied Sciences; TU Delft Civil Engineering and Geosciences)","Hanssen, Ramon (mentor); Verschuur, D.J. (graduation committee); Dheenathayalan, Prabu (graduation committee); Blacquière, Gerrit (graduation committee); Kalkman, Jeroen (graduation committee); Delft University of Technology (degree granting institution)","2018","This work determines whether the amount of frequency components present in the data can be reduced, whilst still retaining image quality, whereas most efforts in seismological research are done in reducing spatial sampling. It is shown using a PCA on the frequency spectra of several data sets that indeed a large redundancy in frequency content is present in onshore seismic data, and an attempt is made to generate a distribution of frequencies in order of importance. Given this redundancy in the frequency spectrum of onshore seismic data, it has been attempted to reconstruct the missing frequencies by applying the Fourier transformation iteratively to the data. However, this transform does not take spatial sampling into account, which is aimed at to compensate for the missing frequencies. Therefore it has been elected to use a linear Radon transformation instead, which keeps components which are connected in space-time connected in the transform domain. A CGNE scheme has been set up to reconstruct the data, which performs very well along the almost linear asymptots in the shot records, up to a reduction of 70% of frequency components. This scheme iteratively applies the linear Radon transform to a shot record, weighing the data in the transform domain with an amplitude based norm. The energy that was spread out due to aliasing because of the missing frequencies is refocused to the main reflectors, especially along the asymptots of the reflection hyperbola. Missing frequencies are reconstructed, up to a scaling factor, and band gaps of up to 6Hz get filled in very well. Next, it is attempted in this work to give quantitative quality metrics, to make comparison between seismic images easier and based on data, rather than subjective visual inspection. Treating migration as a black box, several quality metrics have been devised for the migrated sections: correlation to the ground truth, contrast within an image, average length of found lines, and local SNR. Contrast is not a very good metric to compare between images as its average across an image is almost constant with reduction percentage. The other parameters are good metrics and show a clear trend that the fewer frequency components present in the shot records, the worse the quality of the final image. An increase in deterioration of image quality is observed around 70% reduction, which is in correspondence with the earlier found value for the shot records.","Seismology; Frequency; Sparse inversion; Radon","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:1a15154f-7d08-4c5c-bdc1-4966f958e498","http://resolver.tudelft.nl/uuid:1a15154f-7d08-4c5c-bdc1-4966f958e498","Automated dig-limit optimization through simulated annealing","Hanemaaijer, Thijs (TU Delft Civil Engineering and Geosciences)","Wambeke, Tom (mentor); van Duijvenbode, Jeroen (mentor); Buxton, Mike (mentor); Soleymani Shishvan, Masoud (mentor); Delft University of Technology (degree granting institution)","2018","","dig-limit; simulated annealing; mine planning; dig-lines; optimization; meta-heuristic; ore-waste classification; dilution; ore loss","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:de98f060-7048-49b0-b5bb-4de0cd6e94d2","http://resolver.tudelft.nl/uuid:de98f060-7048-49b0-b5bb-4de0cd6e94d2","Denitrification-based pretreatment for the compaction of silty sands","Hopman, Jessy (TU Delft Civil Engineering and Geosciences; TU Delft Geo-engineering)","Jommi, Cristina (mentor); Dieudonné, Anne-Catherine (mentor); de Kreuk, Merle (mentor); van Paassen, L.A. (mentor); Vos, B. (mentor); van der Star, Wouter R L (mentor); Delft University of Technology (degree granting institution)","2018","Recent developments in bio-based soil improvement techniques include the use of the bacterially mediated process of denitrification to alter engineering properties of soils. Pham (2017) used the denitrification process to stimulate the production of gas and precipitation of calcium carbonate as a soil improvement method. The ability to desaturate a soil to its optimum saturation by means of gas production inspired the use of this method to improve the engineering properties of soils more efficiently by means of a two-stage process of desaturation and compaction. Andrag (2017) started a research to investigate the potential of this concept and developed a test setup for the assessment of its efficiency. The prospects of this biogenic soil pretreatment method are further investigated in the current study. The objective of the research is to assess how the compactability of an initially saturated soil is influenced by the in-situ formation of gas bubbles and if this gas can be used to reduce the energy requirements for compaction of a soil to a given target density. A review on existing literature is initially carried out to grasp the latest developments on this topic. Information from literature is used to determine the typical characteristics of soils on which compaction activities are often found to be ineffective. Based on this information, a representative silty sand with a high gas storage capacity is created for further experiments. It is found that gradation is one of the main properties controlling the water content-dry density relationship of soils. The water content-dry density relationship of soils composed from industrially produced material is found to be often significantly different from natural soils, which can be explained by differences in gradation. A testing strategy is developed and a setup is established for assessment of the concept of biogenic soil pretreatment for reducing energy requirements for compaction. Denitrifying bacteria are cultivated with a chemostat setup which can supply bacterial inoculum for subsequent experiments. The effect of the biogenic pretreatment is evaluated by comparing the energy requirements for compression of treated and untreated soil samples from initial conditions to a given target density with a constant strain-rate. Soil samples are successfully desaturated to targeted saturations by means of an engineered treatment regime. Concentrations of the substrates are determined based on the stoichiometry of the biochemical reaction, Henry’s law, Boyle’s law and the ideal gas law. Gas is produced at a steady rate inside the soil samples with a very limited amount of gas escaping, confirming the high storage capacity of the assembled sample material. The determined optimum saturation of the silty sand (80%), is therefore achieved without exceeding the gas percolation threshold of the soil. The gas that escapes the sample during the gas production stage and the loading stage, is captured with a gas trap that is included in the setup. The changes in water content and dry density of the soil during the experiment can be accurately predicted by means of a volume balance. The major part of the initially available nitrate in the pore fluid is consumed at the end of the experiments, with a limited amount of accumulated nitrite. Moreover, the denitrification process is successfully buffered by including calcium within the engineered substrate solution.
It is initially presumed that energy requirements for static compaction of a silty sand in the Rowe cell can be reduced by bringing the soil closer to optimum conditions in terms of saturation, before starting the loading stage. Based on an analysis of the work input per volume, it is found that the energy requirements for compaction increase slightly as a result of the biogenic pretreatment. In terms of compactability, no clear benefit is obtained from the biogenic pretreatment according to the energy-based assessment method that is used in this research. The slightly higher energy requirements for compaction of treated samples can possibly be explained by the formation of biofilm or entrapment of gas bubbles in the drainage lines of the setup. Cementation effects as a result of calcium carbonate precipitation are not expected to play a role, since calculations show that the relative amount of calcium carbonate in the soil is very limited at the end of the experiments. It is recommended to further investigate the potential of the denitrification-based pretreatment for the compaction of soils by exploring new methods of assessment. It is suggested to focus on implementation of a dynamic loading component to the test method and to investigate the options for execution of a field experiment. Representation of conditions that apply in practice is thereby essential. The potential of biogenic pretreatment for improvement of the engineering properties of silts and clays can also be investigated as it might be a sustainable alternative for the relatively scarce and costly coarse-grained fill material that is normally used nowadays.","denitrification; compaction; desaturation; proctor; nitrogen; biogas","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:db02fb1d-c44a-4f52-adba-6a3877640daf","http://resolver.tudelft.nl/uuid:db02fb1d-c44a-4f52-adba-6a3877640daf","Foams for Enhanced Oil Recovery: Exergy Analysis to Asses Feasibility and Surfactant Screening for Practical Steam Foam Applications","Casquera Garcia, Alberto (TU Delft Civil Engineering & Geosciences)","Farajzadeh, R. (mentor); Jones, S.A. (mentor); Delft University of Technology (degree granting institution)","2018","As the world population is projected to keep growing over the next decades, an increase in energy is required and hydrocarbon fuels will remain as the primary source of energy. Since most of the hydrocarbon resources have been discovered, it is necessary to extend the use of Enhanced Oil Recovery (EOR) methods on these mature fields to increase the fraction of oil recovered. Foam-EOR has shown to improve sweep efficiency during gas injection. However, there are two challenges regarding the use of foams: 1) the performance of the surfactants needed to generate foam and 2) the cost of these surfactants. In this study the performance of six surfactants was tested for steam foam applications; focusing on solubility, thermal stability, foam stability and adsorption in porous media. The solubility of the surfactants ranged from good to poor. However, poor solubility can be enhanced by heating up the solution. The surfactants tested showed a large range of stability behavior, from very good to very poor. The surfactant with the best thermal stability at 275°C has a molecule with three characteristics related to high thermal stability: 1) Sulfonate head, 2) aromatic compound attached to the head, and 3) a long hydrophobic tail (above 18 carbon atoms). The other surfactants, with a low to very low thermal stability lacked one or more of these characteristics. The surfactant with the best thermal stability also had the best foam behavior in porous media at 180°C, showing a max. apparent viscosity of 0.42 Pa·s and a Mobility Reduction Factor of 2818. Finally, for this surfactant, the dynamic adsorption in Bentheimer sandstone was 0.059 mg/grock at 120°C. Additionally, an exergy analysis was carried out to assess the cost of the surfactant from a thermodynamic point of view. For this purpose, the Exergy Recovery Factor was calculated for a system on which the Water Alternating Gas (WAG) and Surfactant Alternating Gas (SAG) EOR methods are applied, with different gases injected. The system includes from the initial capture of the gas and transport of the gas to the final oil and gas production from the reservoir and separation and recirculation of produced fluids. Despite the high exergy cost of the surfactant, the exergy recovery factor was higher for SAG than for WAG, meaning that more energy is extracted than invested. It was also found that less CO2 was produced per barrel of incremental oil extracted with SAG than with WAG.
In this study, fractures in layered rocks are investigated, starting with its geometry and also the stress field contributed to the fracture generation and development. The fracture geometry such as fracture length, average aperture, aperture distribution and orientation are quantified in a two dimension slice image. The study focused on comparing the fracture behavior when (a) the layered rock compositions are the same between samples with increasing confining pressure or (b) the different compositions of layered rocks (different mechanical contrast) between samples in the same confining pressure.
The results show that fracture tends to propagate through layer interface when the mechanical contrast between adjacent layers and the confining pressure are low. The fracture in the weak layer developed at a gentler dip (shear fracture) with higher fracture aperture compared to the ones in the strong layer which almost vertical (tensile fracture). In addition, the shear fracture in the weak layer usually accompanied by the zone of cataclastic flow while the tensile fracture has a more clear pathway for fluid flow.
However, mode I opening/tensile fractures are less likely to affect fluid flow in the reservoir because their aperture is insignificant at depth. While in mode II sliding/shear fractures, only several parts along the fracture that can provide the open space, which depend on the presence of jogs and irregularities on the fracture surfaces.
The results from fracture measurements show that in the weak layer, average aperture and aperture distribution will reduce with the increasing of confining pressure, but increased with the increasing of mechanical contrast. Average fracture aperture and distribution have a significant role in capillary pressure. The higher average aperture will reduce the amount of pressure needed to flow the fluid, while a higher number of aperture standard deviation (aperture distribution) has a contrasting effect. The average aperture has a bigger impact on capillary pressure compare to aperture distribution. Thus, by increasing the confining pressure or decreasing the mechanical contrast, the required pressure for fluid to flow is increasing.
Furthermore, the numerical modeling is performed by imitating the rock mechanical properties and the fracturing conditions from the laboratory experiment. The results show that under compressive stresses, the layered rocks still generate tensile stresses around the interface within the strong layer. The tensile stresses occur because of the stress transfer between adjacent stiff and soft layer with a bonded interface. The presence of tensile stress and the crack-tip stress are responsible for the generation of the tensile fracture in the strong layer for all samples.
The effect of varying the number of confining pressure, Poisson’s ratio and Young’s modulus on the tensile stresses distribution are also performed. The sensitivity study shows that Poisson’s ratio has a more significant impact compared to Young’s modulus on both maximum tensile stress and thickness of tensile region. Higher Poisson’s ratio resulting in higher tensile stresses, while on Young’s modulus it depends on the contrast between adjacent layers rather than the magnitudes.
Understanding the fracture behavior in layered rocks is beneficial for reservoir characterization, as fractures can enhance the permeability and providing vertical connectivity between isolated reservoirs. Accurately interpret 3D natural fracture distribution can help the estimation of the resource and recoverable potential early in field life. It will also contribute to optimizing the well placement and completion design for efficient production planning.","Layered Rocks; Rock Fractures Behavior; Rock Modelling; Stress Distribution","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:18f5c577-a298-4b3b-8cfe-af3050c3ab61","http://resolver.tudelft.nl/uuid:18f5c577-a298-4b3b-8cfe-af3050c3ab61","Utilizing Process-Based Models to Better Incorporate Heterogeneities within Reservoir Modelling","Vacek, Matt (TU Delft Civil Engineering and Geosciences)","Martinius, Allard (mentor); Storms, Joep (mentor); Rossen, Bill (mentor); van der Vegt, Helena (mentor); Delft University of Technology (degree granting institution)","2018","Traditional reservoir modelling utilizes a stochastic approach centered around statistics to generate a 3D representation of the reservoir. While the results of a stochastic approach are favorable, they tend to lack the detail that is necessary to fully understand the different aspects of the reservoir, more precisely, the inclusion of heterogeneities. A possible solution to this problem is the use of process-based models. Process-based models utilize the physical processes involved in the transportation, deposition, and erosion of sediments. As a result, the models generated are more complex in nature and better represent what is found within the subsurface. The use of process-based models within reservoir modelling is a a relatively new process that has yet to be fully utilized due to the difficulty in calibrating the models with well data. Before process-based models can be tested on their viability to include the multi-scalar heterogeneities, the model must be calibrated to match the real-world data. To test this, a combination of field work, lab work, and computer simulations is required. In this experiment, the Roda Sandstone Member, a Gilbert-type delta deposit in Northern Spain, was chosen as the unit of focus. The Roda Sandstone consists of multiple prograding sand lobes, with Roda Y being chosen as the focus of this experiment. The Roda Y sandstone exhibits a predominately medium and coarse grain distribution in the central locations of the sand lobe, and a fine and very fine distribution in the distal locations. Five simulations were run within the process-based modelling software ""Delft3D"", each with varying sediment input parameters, to observe the effects on the results. The results for the simulations show a strong calibration for each of the five simulations for coarse and medium grained sand, with a percent difference between the model results and the field data of 4-8%. The fine and very fine data contain a higher average difference between the two data sets, ranging from 18-23%. The difference for mud averages around 11%, with predominately more mud being deposited within the simulations. The large differences for the fine and very fine grained can be attributed to the difference in the size and shape of the sand lobe produced by the simulations. In locations were the two data points are equivalent in regards to depositional location within the sand lobe, a high correlation is observed. The results indicate that process-based models have the potential to be a very useful took within reservoir modelling. As this is the first step in a series of steps, additional testing is required for the additional aspects involved in utilizing process-based models to better incorporate heterogeneities within reservoir models.","Delft3D; Process-based modelling; Roda Formation; Heterogeneity","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:a3717fef-f895-4ed8-b492-decfad4870be","http://resolver.tudelft.nl/uuid:a3717fef-f895-4ed8-b492-decfad4870be","Heat Exchange in Tensile Fractures: an Experimental and Numerical Approach","Balmer, Marco (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Engineering)","Bruhn, David (mentor); Barnhoorn, Auke (mentor); Bakker, Richard (mentor); Vossepoel, Femke (graduation committee); Delft University of Technology (degree granting institution)","2018","Geothermal energy is a relatively sustainable energy source of which the essence is to extract heat from hot subsurface rocks. Circulating fluids serve as the transport agent of heat. The contact area between the fluids and the rocks is where the relevant heat transfer occurs, i.e., where the water is heated up. In some geothermal reservoirs, this circulation occurs naturally through porous matrix (mainly sediments) or through heavily fractured formations. Enhanced geothermal systems (EGS) are potentially favorable reservoirs where subsurface permeability is increased by means of artificial stimulation techniques. These stimulation techniques often involve hydraulic fracturing where a limited existing fracture network is expanded or “enhanced” by injecting fluids under high pressure conditions. While the geometry of the generated fractures influences permeability, the effect on heat exchange has received less attention. This thesis discusses the effects of fracture geometry on the heat transfer between solid and fluid. Along with laboratory experiments, numerical simulations were conducted. All investigations were performed on igneous granite rocks. Tensile fractures were generated to allow a fluid flow along the otherwise impermeable rock samples. Several parameters were varied throughout the experiments and simulations including volumetric flow rate, fracture aperture, rock temperature and fracture geometry and surface area in order to investigate their impact on heat transfer processes. Flow rate variations in the experiments have shown that higher flow rates cause the fluid to absorb less heat per unit volume and cause the rock to cool down more extensively, therefore thermal depletion of the reservoir is likely to occur within a shorter time frame. The dependency of exchanged heat on fracture aperture variations (in the range of 0.05 to 0.5 mm) did not yield a clear trend within the experiments, but does so in numerical simulations. Aperture variations in the numerical simulations did not cause notable differences in transferred heat as long as the volumetric flow rate is kept constant. However, as the fluid velocity is kept constant the amount of fluid flushed along the fracture per unit time is affected by varying apertures. This causes a difference in heat transfer as well. Increased fracture surface areas alone (more extensive topology/roughness) have shown a minimal impact on the heat production while a more extensive fracture network (additional branches) has shown notable enhancement in the amount of heat produced. Cooling behavior of the rock has shown correlations with Newton’s law of cooling and suggests a limitation of heat production by the heat conduction occurring within the rock.
Experimental findings cannot directly be compared with natural reservoir conditions. The reason for this is a thermal equilibrium that is achieved at each flow experiment, i.e., the heat withdrawn equals the heat resupplied by a heater. In natural reservoirs this is often not the case where a cold front propagates towards the production well and determines the lifetime of how long heat can efficiently be produced from a certain rock mass. This results in an unsteady heat conduction where the heat withdrawn does not equal the heat resupplied.","Geothermal Energy; Heat transfer; Fracture; Laboratory experiment; Numerical Simulation; Enhanced Geothermal System","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:e13e5255-c2c2-461d-977b-334ef236713b","http://resolver.tudelft.nl/uuid:e13e5255-c2c2-461d-977b-334ef236713b","Lateral persistency of precession-driven floodplain cycles and their relation to fluvial sandbodies","de Lanoy, Jasper (TU Delft Civil Engineering & Geosciences; TU Delft Geoscience and Engineering)","Abels, H.A. (mentor); Storms, J.E.A. (graduation committee); Lindenbergh, R.C. (graduation committee); Delft University of Technology (degree granting institution)","2018","Accurately predicting the subsurface architecture is essential in finding potential reservoirs for subsurface engineering purposes. The architecture of the deposits is determined by both autogenic (internal) and allogenic (external) controls on the fluvial system and its deposition of sediments. However, the extents to which each of the two controls have an influence and how they interact in fluvial systems, is not sufficiently known for predicting the architecture of the deposits. Allogenic astronomical cycles have a trend which can be extracted from the deposits, leaving autogenic variability. This thesis means to find the lateral and vertical persistency of externally-driven floodplain deposits and their relation to the fluvial sands. Photogrammetry panels of the Early Eocene Willwood Formation (Bighorn Basin, USA) have been interpreted, a formation in which previous studies have found a pattern matching precession, one of the astronomical cycles. The formation consists of two floodplain facies in successions, together with a sandstone channel facies. Previous researches focused on the floodplain successions stratigraphically and only limited on the sandstones; this thesis means to find the lateral and vertical persistency of the floodplain successions and how these sandstones relate to the successions. The two floodplain facies, overbank deposits and heterolitics, form successions with an average thickness of 6.9m and standard deviation of 1.3m, measured over a maximum distance of 3.0km parallel and 2.8km perpendicular to the paleoflow direction. The longer the distance along which the successions are measured, the larger the range and standard deviation of an individual succession is and the more the average thickness converges to the average thickness of 6.9m. The average thickness over the 28 successions indicates a cyclicity period of 20.9kyr, matching precession cyclicity. The sandstones are subdivided into two classes based on their thickness: minor and major. The minor sands are observed to occur in the heterolitics layer of the floodplain successions. The average major sandbody thickness is 14.0m with a standard deviation of 3.9m, based on 13 bodies. Though most being multistory, it is thicker than results from previous research in the area. Opposed to the minor sands, there is not sufficient data and information on the major sands to confirm a depositional model. For the floodplain successions steps have been made to predict their behavior; once there is sufficient data to determine the role of the sandstones, prediction of the full alluvial architecture is enabled.","Willwood Formation; Bighorn Basin; autogenic; allogenic; fluvial deposits; Milankovitch Cycles; orbital climate change","en","master thesis","","","","","","","","2023-09-18","","","","Applied Earth Sciences","",""
"uuid:3890a9fa-d16c-43a9-bcf2-d5f5dbf1f68d","http://resolver.tudelft.nl/uuid:3890a9fa-d16c-43a9-bcf2-d5f5dbf1f68d","Effect of Mineral Scaling on Geothermal Wells: Carbonate Scaling","Rajvanshi, Ullas (TU Delft Civil Engineering & Geosciences)","Vardon, P.J. (mentor); Voskov, D.V. (mentor); Delft University of Technology (degree granting institution)","2018","As of 2040, Energy Information Administration (EIA) expects an increase of 28% in world energy consump- tion. The majority of this consumption is projected to account from developing countries such as India, China and other third world countries since the economy is increasing rapidly. [3]
In order to overcome this fast increase, the human kind cannot rely only on fossil fuels and other sustain- able technologies like solar, wind, geothermal are required. However, the emmision of CO2 is also increasing from 6000 million metric tons carbon in year 2000 to 10000 million metrics tons in 2010. That’s why many countries such as Denmark, Norway, Germany, The Netherlands etc., are moving away from traditional fuel sources to the new energy. One of these energy is Geothermal energy. Despite the fact that geothermal is a clean energy and almost CO2 emission free, it does have some challenges mainly, scaling and corrosion. Moreover, thats not the only problem associated with this. Scaling is site spe- cific which is a major problem in the wells.","Geothermal Energy; Scaling; Geo-Engineering; Carbonates","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:dbd01d9a-887a-4493-b318-7a04d1939508","http://resolver.tudelft.nl/uuid:dbd01d9a-887a-4493-b318-7a04d1939508","Foam-Assisted Chemical Flooding at Reservoir Conditions","Al Mutawa, Abdulaziz (TU Delft Civil Engineering and Geosciences)","Zitha, Pacelli (mentor); Rossen, Bill (mentor); Bertotti, Giovanni (mentor); Vincent-bonnieu, Sebastien (mentor); Delft University of Technology (degree granting institution)","2018","Despite recent drop in the growth of global oil demand, the trend is expected to gradually pick up and continue increasing. Industrial and transportation sectors are still considered the highest consumers of oil. The petrochemicals sector’s demand for oil is increasing sharply and expected to continue in that fashion for the upcoming years. As oil fields age and mature, extraction of oil via primary and secondary techniques becomes, to an extent, inefficient. That encourages more research and development in enhance oil recovery (EOR) methods. In EOR, the aim is to either change a physical or chemical property of reservoir fluid in order to improve the oil recovery factor. The techniques can be categorized as thermal, physical, chemical or gaseous. In this experimental study, the lessons learned from gas flooding methods and surfactant flooding methods are taken into account in order to come up with a novel Foam-Assisted Chemical Flooding (FACF) procedure that aims to enhance the oil recovery factor to its maximum. In this approach, a surfactant slug solution is injected into a core at residual oil after water flooding conditions to mobilize trapped oil by capillary pressure. Then, a surfactant drive solution is co-injected with N2 for foam generation to serve as mobility buffer displacing the accumulated mobilized oil. The experimental study is performed under reservoir conditions of 90 ±1oC temperature and 20 bar of back pressure. In this study, surfactant stability is tested in synthetic formation brine. Then, phase behaviour tests are conducted to identify the capability of the surfactant to reduce o/w interfacial tension (IFT) to ultra-low values. The resulting solutions are categorized into their associated Winsor Types and classified based on salinity as under-optimum, optimum and over-optimum. A final surfactant slug solution is formulated based on these tests. Afterwards, bulk foam tests are performed in absence and presence of crude oil to test surfactant foaming ability and the resulting from stability and strength. Core-flood experiments are carried out to assess the possibility of generating foam in porous media in absence of crude oil and at residual oil to waterflooding. Full EOR FACF experiments are conducted, two at under-optimum and two at optimum salinity conditions. Two FACF experiments are performed with the assistance of medical CT scanner. In one FACF experiment, the foam is pre-generated utilizing a mixing tee and then injected into the Bentheimer sandstone. The study reported here showed that surfactants are not stable in synthetic seawater injection brine, as it tends to form complexes in presence of divalent ions, and subsequently generate precipitations. Stability was achieved by removing the divalent ions from the synthetic brine. In addition, phase behaviour study yielded that surfactant (A) is a better o/w IFT reduction agent than surfactant (B). A distinct layer of micro-emulsion was observed in excess of water and oil phases. On the other hand, surfactant (B) displayed better foaming abilities than surfactant (A) in absence of crude oil. Using surfactant (B), foam was generated in multiple qualities in a Bentheimer sandstone core-flood experiments in absence of crude oil. The critical foam gas fraction was found to be 75%. However, attempts to generate foam in porous media at residual oil to water flooding conditions were not successful. In three FACF core-flooding experiments, weak and unstable foam was generated during the surfactant drive co-injection phase. Whereas, in the last FACF experiment where a mixing tee was utilized, pressure drop and gas breakthrough data show that stable foam was generated. The CT images from two FACF experiments, one at optimum and the other at under-optimum salinity conditions displayed unstable water front in waterflooding phase, and unfavourable mobility conditions, during the surfactant slug injection. However, the effect of salinity conditions was seen in the different oil bank shapes in both experiments. The one at under-optimum salinity condition showed more unstable front. The study reported here showed that the FACF technology yields improving oil recovery of 70±5%, 77±5% and 73±5% for the FACF experiments where it was very challenging to generate foam in-situ and reached up to 80±5% of oil initially in place in the case where foam was pre-generated outside the core (55%, 61%, 59% and 46% are the oil recovery factors after waterflooding, respectively). The study revealed that drive foam strength has a bigger impact than its surfactant slug salinity.","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:c6924adf-9f7b-4850-8099-056eb06bc11a","http://resolver.tudelft.nl/uuid:c6924adf-9f7b-4850-8099-056eb06bc11a","Optimization Strategies of CO2 Injection for Sequestration and EOR","Chen, Yuan (TU Delft Civil Engineering and Geosciences)","Voskov, Denis (mentor); Delft University of Technology (degree granting institution)","2018","The current situation with green gas emission requires the development of low carbon energy solutions. However, a significant part of the modern energy industry still relies on fossil fuels. To combine these two contradictory targets, we investigate a strategy based on a combination of CO2 sequestration with Enhanced Oil Recovery (EOR) in the hydrocarbon reservoirs. In such technology, the development of miscibility is the most attractive strategy from both technological and economic aspects.
Modeling of this process involves solving complex nonlinear problem describing compositional flow and transport in highly heterogeneous porous media. An accurate capture of the miscibility development usually requires an extensive number of components to be present in the compositional problem which makes simulation run-time prohibitive for optimization. Here, we apply a multi-scale reconstructing of compositional transport to the optimization of CO2 injection. In this approach, a restriction operator, based on the parametrization of injection and production tie-lines, is constructed following the fractional flow theory. This operator is tabulated as a function of pressure and pseudo-composition which then is used in the Operator-Based Linearization (OBL) framework for simulation. As a result, a pseudo two-component solution of the multidimensional problem will match the position of trailing and leading shocks of the original problem which helps to accurately predict phase distribution. Applying a simple prolongation operator, based on interpolation between injection and production compositions, a compositional solution with the correct reconstruction of two-phase region can be obtained.
The reconstructed multicomponent solution can be used then as an effective proxy-model mimicking the behavior of the original multicomponent system. In this study, we use this proxy-model in the optimization procedure which helps to improve the performance of the simulation with the increasing intricacy of the reservoir model. In this work, the nonlinear constrained optimization function is applied to find optimal pressure values for CO2 injection process to acquire a highest Net Present Values (NPV). Starting with the limited number of the controls, the global extrema of the objective function can be determined from both full physics model and proxy model. The result shows that both models can converge to the similar extrema given various initial guesses. It is noting that for multicomponent system, the proxy model can also have salient accuracy to predict the NPV extrema compared with the original full model.
As a result, the reconstructed proxy model can be significantly cheaper than a full conventional compositional model. An additional benefit of the proposed methodology is based on the fact that important technological features of CO2 injection process can be captured with lower degrees of freedom which accelerates the optimization process.","CO2 injection; Optimization; Compositional modeling; Enhanced Oil Recovery; Carbon capture and storage","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:377ef44a-fc4e-46d7-a61e-0803f50a4f94","http://resolver.tudelft.nl/uuid:377ef44a-fc4e-46d7-a61e-0803f50a4f94","Liquid Injectivity is SAG Foam EOR","Flores Martinez, Wendy (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Engineering)","Rossen, Bill (mentor); Gong, Jiakun (mentor); Vincent-bonnieu, Sebastien (mentor); Delft University of Technology (degree granting institution)","2018","EOR processes employing gas injection can be very efficient in recovering oil where the gas sweeps. Unfortunately, gas injection has poor sweep efficiency because or reservoir heterogeneity, viscous instability and gravity segregation of injected gas to the top of the formation. Foam can improve the sweep efficiency in gas injection in Enhanced Oil Recovery. The best injection strategy to overcome gravity override in homogeneous reservoirs is a SAG process with a large slug of surfactant followed by a large slug of gas. An additional advantage of SAG injection is increased gas injectivity. Water is displaced from the near-well region where foam weakens, this raises gas mobility and increases injectivity. However, during liquid injection, the injectivity is considered to be poor.
Liquid injectivity is not fully understood during SAG process. In this study several core-flood experiments were conducted to investigate how injectivity is affected by the injection strategy. Through these experiments, it has been found that the gas injection flow rate has no significant effect during the gas injection period, foam collapses after roughly the same number of pore volumes of gas injected regardless of the injection rate.
During the liquid injection period, liquid was injected at different flow rates following a gas injection period. The results suggested a moderately shear-thinning behaviour. Liquid injection rate was increased 10, 40 and 100 times, but the rise in pressure gradient is not proportional to the increment in injection rate.
Furthermore, the effect of the size slug injected was investigated on the subsequent liquid injection. Results show that during prolonged periods of gas injection after foam, a region near the inlet is formed in which the gas mobility is much greater and the liquid mobility is much greater than downstream during the subsequent liquid injection. The bigger the gas slug size, the better the subsequent liquid injectivity in the nearest region to the inlet.
The effect of foam quality was studied; it has been found that foam quality has no big effect during the subsequent gas and liquid injections. The results of foam injection at 0.60 and 0.95 quality followed by gas injection show that foam collapsed after roughly similar number of pore volumes injected regardless of foam quality. During the liquid injection period the trends of the pressure gradient were similar at foam initial quality injection 0.60 and 0.95.
Finally, in order to verify the capability of the radial model developed by Gong et al. \cite{Gong}, the experimental data was fitted to the linear-flow and radial-flow models. The results suggest that the simulation based on Peaceman equation underestimated the gas and liquid injectivity in SAG process, and furthermore, the conventional simulator cannot represent the effect of gas injection on the subsequent liquid injection.","Foam; SAG; EOR; INJECTIVITY","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:9fbd867a-fc1f-45ce-ac78-a5e7ad1921d4","http://resolver.tudelft.nl/uuid:9fbd867a-fc1f-45ce-ac78-a5e7ad1921d4","Statistical Analysis of Geotechnical Parameters in Starnmeer and Alkmaardermeer: Dike Stability analysis","Bitar, Zeid (TU Delft Civil Engineering and Geosciences)","Hicks, Michael (mentor); de Gast, Tom (mentor); Delft University of Technology (degree granting institution)","2018","The aim of this thesis report is to analyze slope stability parameters given by HHNK for the dike around a polder located in the province of North-Holland, “Starnmeer”, and a lake located to the west of it called “Alkmaardermeer”. Most of the dike has been reported to be too low in some places and plans of restoration will be implemented in 2019. A RFEM (Random Finite Elemental Method) analysis is to be done in collaboration with TU Delft and HHNK on these dikes to identify slope failure probabilities, where the input data is to be addressed in this report. Starnmeer contains thick layers of peat and clay until a depth of approximately -5 meters NAP, where a large sand aquifer begins to much larger depths. For geotechnical analysis, the first few meters are of primary concern, so only the thick peat and clay layers will be assessed. Rising water levels proves problematic for the polder, but fortunately drainage opportunities to adjacent water bodies is possible. The addition or reduction of water heavily influences soil behavior by affecting underlying pore water pressures and stress states. Parameters to be analyzed include wet bulk density, dry bulk density, water content, cohesion, and the friction angle. A statistical analysis and distribution of each parameter provide meaningful insight on probabilities and disseminations of measurement data. The clay layer was found to have a significant amount of sand and silt, affecting the porosity, sorting, cohesion, and bulk densities resulting in an uncompacted porous clay layer. The peat layer is also highly saturated, highly organic, and rather loose. The layers are hence prone to heaving and rapid primary consolidation. By classifying each of the five parameters for both regions to be normally distributed or lognormally distributed, the data can be then standardized and correlated to each other to determine linear dependencies. The relations heavily vary depending on the environmental setting and other physical aspects. For instance, the wet and dry bulk densities are found to have a strong positive correlation with each other in Starnmeer but not in Alkmaardermeer. The layers were found to be heavily saturated, which negatively influences the correlation between water content and bulk densities. Cohesion and friction angle are primarily dependent on the consistency, shape, and packing of the soil grains, so low to no correlation was established.","","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:fd2707f0-4b14-4e96-b35f-e79b91417542","http://resolver.tudelft.nl/uuid:fd2707f0-4b14-4e96-b35f-e79b91417542","Multi-proxy analysis of the sedimentary and climatic response to the Palaeocene-Eocene Thermal Maximum in the Hengyang Basin, Hunan Province, China","Mäder, Mäde (TU Delft Civil Engineering & Geosciences; TU Delft Geoscience and Engineering)","Abels, H.A. (mentor); Storms, J.E.A. (graduation committee); Vizcaino, M. (graduation committee); Delft University of Technology (degree granting institution)","2018","The Paleocene-Eocene Thermal Maximum (PETM) was a time of relatively abrupt climate change with intensive atmospheric greenhouse warming of 5 - 8˚C and is regarded as quasi-analogous for the modern anthropogenically-induced global warming. It therefore attracted considerable attention from geologists over the last decades. The PETM occurred 56 million years ago and is characterized by a sharp negative δ13C isotope excursion which has been observed in terrestrial and marine sediment records the world over. The PETM global warming led to a significant alteration in regional climate and to an enhanced hydrologic cycle which triggered an increase in weathering and sediment discharge from catchments to basins.
The sedimentary, biotic, and climatic responses to the PETM have been studied intensely on the American and European continents. However, detailed analyses of the impact to the PETM on the Asian continent remain rare. Here, a detailed analysis of the sedimentary and climatic response to the PETM in the Hengyang Basin, Hunan Province, China, is presented. High-resolution isotope measurements of pedogenic carbonate nodules reveal the characteristic isotope excursion of the PETM and strongly improve the previous low-resolution isotope series. Pedogenic features and clay types of PETM floodplain deposits indicate oxic conditions and a climate with pronounced seasonality in which intensive dry periods alternated with wet seasons. Grain size analysis of the paleosols support the hypothesis of coarsening deposits as a response to the PETM even though the coarsening is not strongly pronounced. Sediment bypassing and a depleted regolith in coarse material is suggested as the main reasons for the only minor pronounced coarsening in the PETM units. A generalized PETM model, which was simulated in PaCMod, a spatially lumped numerical model developed at the University of Delft, Netherlands, predicts an increase in net precipitation and erosion in the catchment area during the PETM. As a result, the simulated water discharge increases and lead to increased bedload and suspend load transport within the river system. These modelled results are correlative with the geological findings in the Hengyang basin. The Chinese terrestrial PETM record studied here corroborates the global continental impact of the greenhouse warming event through a shift towards pronounced aridity alternating with intensified wet seasons resulting in an oxic floodplain environment with a minor coarsening in grain size.
This study concentrates on the Eridanos Delta and identifies the properties of the delta in terms of its progadation distance and sedimentation rate and compare different time models to the ones provided by Overeem (2001) and Kuhlmann (2008). Furthermore, studies the reservoir rocks in terms of their petrophysical properties and facies distribution. Moreover investigates the reasoning behind the shallow sediments gas accumulations and factors behind the concentration of all the discoveries around the A and B blocks. Lastly, constructs a 3D model of the reservoirs distribution in the study area and their properties by integrating the study results of geological, geophysical, petrophysical and reservoir engineering data.
Such results were achieved by interpreting a high resolution 3D seismic survey and 2D lines in combination with wells’ wireline logs and core data. Seismically, a total of 12 units were mapped to categories the successions (3.6 – 1.8Ma) that deposited post the Mid Miocene Unconformity. In addition, more than 20 wells were used to understand the reservoir properties in which seven wells have cores. Sedimentological aspects were assessed by studying the descriptions of cores and thin sections and the measurements of the core plugs. Gas accumulations were studied by evaluating the production data for gas and linking the gas to its source.
Bulk experiments enabled the establishment of master curves showing viscosity and screen factor dependences on accumulated energy during pre-shearing, regardless of shear origin. The injected unsheared polymer solution has an 퐹푅 of 1.6 and an injectivity gradient, e.g. ratio of resistance factor over 10 pore volumes, of 2.4. All injected pre-conditioned solutions have an 퐹푅 in the optimal range between 1 to 1.2. By imposing 15 MJ/m3, the disperser-sheared solution improves the injectivity by decreasing the injectivity gradient to 1.3, while the viscosifying power is reduced by 2% and the screen factor by 30%. To reach the same injectivity gradient of 1.3 with Ultra-Turrax, 31 MJ/m3 were imposed, which reduces the viscosity and screen factor by 11% and 44% respectively. The sheared solution into a capillary imposes 50 MJ/m3, giving an injectivity gradient of 2.7. Both viscosity and screen factor are reduced by 19% and 53% respectively. This indicates that the injectivity performance is shear-origin dependent and the resulting polymer structure, when sheared through contractions, has a different alignment as compared to shearing with the agitators, the disperser and Ultra-Turrax.
In conclusion, the rheological dependencies of sheared polymer solutions form a master curve dependent of accumulated energy during shearing with different shearing devices. Further, the proven beneficial impact of pre-conditioning with agitators before injection enables a better utilization of polymer flooding operations by reducing the risk of pore plugging.","polymer flooding; EOR; emulsion polymer","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:7108bd2b-80de-4884-b90c-6239e27b3214","http://resolver.tudelft.nl/uuid:7108bd2b-80de-4884-b90c-6239e27b3214","A Dynamic Multilevel Multiscale Framework for Accurate and Efficient Simulation of CO2-Brine Multiphase Flow in Heterogeneous Porous Media","Rijntjes, Jeroen (TU Delft Civil Engineering and Geosciences)","Hajibeygi, Hadi (mentor); Cusini, Matteo (mentor); Delft University of Technology (degree granting institution)","2018","One of the most important challenges facing academic, industrial and policy-making sectors is meeting with the increasing energy demand while preserving the affordability of the energy and maintaining the quality of the planet earth (including the environment, specially by reducing its greenhouse gas footprint). This global challenge demands for exploiting the subsurface formations as giant storage space for industrial by prod- ucts, e.g., CO2, while a future utilisation is found for them. Exploitation of subsurface formations for CO2 storage depends on our capacity to “accurately” and “efficiently” simulate the multiphase nonlinear flow in heterogeneous large-scale natural formations. An accurate and efficient simulation would allow for proper predictive understanding for several operational aspects including: (1) capacity of the storage; (2) life-time long behaviour of the injected CO2 in the subsurface formation, and (3) safety and integrity of the capturing procedure. The challenge of extreme scale dissimilarity between the heterogeneous coefficients (rock con- ductivity and fluid physics, e.g., mixing) and the reservoir has been known in the scientific literature as one of the main simulation challenges. Classically, to resolve this mismatch, reservoir models have been exces- sively upscaled to a resolution which can be solved affordably with the state-of-the-art commercial-grade simulators. However, as the rapid extension of the computational capacity, as well as the newly developed multiscale scalable nonlinear solvers, one needs to revisit our simulation frameworks to provide a scalable (to field scale) and accurate CO2 simulation framework. This thesis work focuses on extension of the recently developed Algebraic Dynamic Multilevel Method (ADM) to highly-nonlinear simulations of CO2-Brine multi- phase flow problems. ADM maintains simulation scalability by imposing fine-scale grids only where needed; and imposing coarser grids paired with accurate prolongation operators far from the sub-domains with sharp gradients. In this work, to provide a systematic study, the developed ADM framework is formulated such that it allows for both multiscale-based basis functions and also upscaling-based procedure. This is crucially im- portant as it reveals how the ""solution-based” interpolations based on fine-scale heterogeneity can impact the simulation results; compared with the “effective-coefficient-based” approach.
In brief, the novelty and contribution of this research is two fold: (1) development of a multiscale-based ADM method for CO2-Brine simulator and (2) systematic study to find the best model order reduction strat- egy when it comes to complex multiphase characteristics and rock heterogeneity. Two different classes of simulations are studied: (1) injection and evolution of the injected CO2 phase into the brine with capillary effects; and (2) miscible mixing process in which resolving front fingers into the residing less-mobile fluid imposes computational challenges. The study, as such, intends to reveal the details in “upscaling-based” vs. “multiscal-based” approach; and tends to provide a generic framework in which the scalability of the simu- lations are preserved by employing fine-scale grids only where and when needed.
Several challenging sensitivity analysis are performed in which fine-scale solutions are compared with the multi-scale ADM and upscaling ADM solutions for immiscible and miscible fluid flow displacement. From these numerical experiments can be concluded that Multiscale-ADM outperforms the Upscaling-based ADM approach. More precisely with similar active grid cells, it provides a more accurate simulation method. As such, Multiscale-ADM casts a promising approach for next-generation simulators for CO2-Brine systems.","ADM; CO2; Simulation; Reservoir; sequestration; upscaling; multi-scale approach","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:40a7ea8a-8a07-45cc-ad39-16cc975442da","http://resolver.tudelft.nl/uuid:40a7ea8a-8a07-45cc-ad39-16cc975442da","Breakthrough time of a geothermal reservoir: Estimating the impact of well spacing, reservoir and operational inputs on the breakthrough time of a geothermal doublet","van Rijn, Sophie (TU Delft Civil Engineering and Geosciences)","Daniilidis, Alex (mentor); Bruhn, David (mentor); Delft University of Technology (degree granting institution)","2018","This research identifies and provides a relative ranking of the parameters that control the thermal breakthrough time of a geothermal doublet. The ranking is based on simulations modelled by a three-dimensional model build in COMSOL Multiphysics with a simulation duration of 50 years. The model is a nonisothermal, isotropic, cuboid consisting of a sandstone aquifer surrounded by identical impermeable layers. The ranking is derived based on a solution space covering a minimum, maximum and mean value for each of the simulation parameters. The investigated simulation parameters are the density, porosity, permeability, thermal conductivity and specific heat capacity of both the surrounding rock formations and the aquifer, the depth and thickness of the aquifer, the flow rate, injection temperature and the well spacing. The mean values of the solution space form the base model, from which the parameters will divert separately to monitor the model’s behaviour on the varying parameters.
In this research, the breakthrough time is defined as the time at which the production temperature is decreased by 1% to 99% of its initial value. The ranking is based on comparing the proportional change of each parameter from the base model to the change in breakthrough time. The results show that the thickness, flow rate and the well spacing are the most crucial parameters influencing the thermal breakthrough time of a reservoir. Overall, the flow rate has the greatest impact, with a decrease of 16.7 years between a flow rate of 150 m3/hour and 250 m3/hour.
In addition, the surrounding rock parameters have a notably smaller impact on the thermal breakthrough time compared to the reservoir rock and process parameters. The surrounding rock parameter with the relatively largest impact on the breakthrough time is the specific heat capacity, which is only a change of 0.2 years between a specific heat capacity of 1150 and 1250 Jkg-1K-1.","breakthrough time; geothermal doublet","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:650e76d9-6342-4f69-83ea-9aa2f574799b","http://resolver.tudelft.nl/uuid:650e76d9-6342-4f69-83ea-9aa2f574799b","Methods For Feature Extraction of an Outcrop Using Terrestrial LiDAR: Methods For Feature Extraction of an Outcrop Using Terrestrial LiDAR","Pahal, Surya (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Remote Sensing)","Lindenbergh, Roderik (mentor); Storms, Joep (graduation committee); Delft University of Technology (degree granting institution)","2018","The following report brings to light how LiDAR data of an outcrop can be acquired and subsequently processed in order to extract the geometry of the outcrop and its pertaining parameters. It makes the use of a sandstone outcrop in the Trooz quarry, Belgium, near Liege. The outcrop was scanned using a terrestrial laser scanner, after which the point cloud data recorded information, pertaining to position and intensity was then processed and subject to interpretation. The report aims to systematically and chronologically take the reader through the entire workflow used by the author, its drawbacks and advantages. Whilst providing a specific analysis of the outcrop in question, creating a general guideline is also an aim. Prior to the processing the significance of the geologic history of the area is touched upon along with the practical acquisition of that data, concerning equipment and procedure. The physical principles of LiDAR and other possible options of acquiring data such as photogrammetry are explained, each with their benefits and shortcomings. The practicality of LiDAR is especially analysed followed by explanation and usage of processing methods such as registration, geo-referencing and computation of geometrical parameters, specifically with the help of software’s such as CloudCompare and MATLAB. Once the results of such parameters are derived, their integrity is discussed by comparing MATLAB oriented methods to those of CloudCompare. These quantified results include values of dip angle and direction over the entire outcrop and the corresponding normal vectors. Varying roughness over the surface of the outcrop and analysis of the intensity distribution present. Whilst also validating these results by comparing them with manual recorded results of dip angle and direction taken at the site. The significance of these parameters is discussed and their application in the characterization of layering. Finally, suggestions regarding the methodology both during acquisition and processing such as during geo-referencing are made by displaying obstacles encountered and flaws realized in the author’s own work.","LiDAR; Scanner; Outcrop; Feature Extraction","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:5c612a8b-b285-41b1-a8a4-0e42e4045a01","http://resolver.tudelft.nl/uuid:5c612a8b-b285-41b1-a8a4-0e42e4045a01","Gas flow through methane oxidation systems: A laboratory and numerical study for optimising system design","van Verseveld, Charlotte (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Engineering)","Gebert, Julia (mentor); Heimovaara, Timo (mentor); Hajibeygi, Hadi (mentor); Delft University of Technology (degree granting institution)","2018","English:
Landfills have been indicated as a major methane source. Methane oxidation systems are `low technology' systems that can treat these methane emissions. Yet, methane oxidation systems are herein still sub-optimal and leave room for improvement. A numerical model was established to research the effective gas permeability ratio between the gas distribution layer and the methane oxidation layer, and the centre-to-centre distance of the gas inlet points, necessary to achieve a spatial homogeneous methane load. In order to relate the permeability ratio to the design choice for the materials, laboratory experiments were performed to asses the influences of compaction level, hydraulic conditions and physical properties of a soil on the effective permeability of that soil. Overall, it is concluded that the effective permeability is predominantly influenced by the compaction level and soil texture. The water saturation only has a significant influence at near saturated levels. This means that the choice of suitable material and adequate construction practice has more effect on the effective permeability than seasonal changes in saturation levels in moderate climates. Furthermore, it is concluded that there are two parameters that govern the spatial homogeneity of the methane fluxes from the gas distribution layer into the methane oxidation layers: the permeability ratio between these layers, and the centre-to-centre distance between the inlet points. The required permeability ratio increases quadratically with an increasing centre-to-centre distance.
Nederlands:
Stortplaatsen zijn aangeduid als een belangrijke bron van methaanemissies. Methaanoxidatiesystemen zijn technisch simpele systemen die het stortgas kunnen saneren. Op dit moment zijn de bestaande methaanoxidatiesystemen nog weinig efficiënt en is het noodzakelijk om de homogeniteit van de laterale distributie van het stortgas te optimaliseren. Er is een numeriek model gegenereerd om inzicht te geven in de benodigde ratio tussen de effectieve permeabiliteit voor gas van de gasdistributielaag en van de methaanoxidatielaag, en in de maximale hart-op-hartafstand tussen de gasinlaatpunten om deze lateraal homogene methaan distributie te bereiken. Om de effectieve permeabiliteitsratio te relateren aan de materiaalselectie zijn er laboratoriumexperimenten uitgevoerd, die de invloeden van het compactieniveau, de hydraulische condities en de fysieke grondeigenschappen op de effectieve permeabiliteit voor gas vaststellen. Al met al kan worden geconcludeerd dat de effectieve permeabiliteit hoofdzakelijk wordt beïnvloed door het compactieniveau en de grondtextuur. Het watergehalte blijkt alleen significante invloed te hebben onder bijna verzadigde omstandigheden. Dit betekent dat een geschikte materiaalkeuze en adequate constructie de effectieve permeabiliteit voor gas meer beïnvloeden dan de seizoensgerelateerde veranderingen in het watergehalte in gematigde klimaten. Daarnaast kan worden geconcludeerd dat twee parameters bepalend zijn voor de laterale homogeniteit van de methaanstroom van de gasdistributielaag naar de methaanoxidatielaag: de ratio tussen de effectieve permeabiliteit voor gas tussen deze twee lagen, en de hart-op-hartafstand van de gasinlaatpunten. De benodigde permeabiliteitsratio neemt kwadratisch toe bij een toenemende hart-op-hartafstand.","Methane oxidation; Landfill; Gas flow; permeability","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:57192922-7ec7-4592-88d6-fd7506fb327a","http://resolver.tudelft.nl/uuid:57192922-7ec7-4592-88d6-fd7506fb327a","Comparing WWII aerial photographs to Sentinel-2 data","Sassen, Tom (TU Delft Civil Engineering and Geosciences)","Lindenbergh, R.C. (mentor); Lannini, Lorenzo (graduation committee); Kreuger, Bas (graduation committee); Delft University of Technology (degree granting institution)","2018","During World War II West Papua was the scene of war between the Axis and the Allies. In this case, it was the Japanese on one side Australian and US forces on the other. After the war a lot of equipment was left in the jungle and because of the low population density on the island some material can still be found to this day. Planes and vehicles that were abandoned far enough from villages were able to withstand the test of time and are still hidden under the trees. In November 2018 an expedition force is heading to the island to find some of these planes. This assignment was meant as a preparation for that expedition and it was my job to find places that could be interesting to investigate closer in the field. The research question that had to be answered was as follows: is it possible to classify and link historical data to modern data. To do this I looked at old aerial photographs of the airports, and at modern Sentinel-2 and Landsat multispectral images of the area. The aerial photographs are stitched into a panorama and geolocated so that the coordinates were known. Next features like the average and gradient of surrounding pixels are computed so the image could be classified. Classifications were then performed on the panoramas and on the Landsat 8 dataset in order to create a map of the region of interest and possibly point out potential war equipment locations. The Landsat data was also used to create a heatmap to show the warmest spots in the region. These spots could potentially point to material that is warmer than its surroundings, e.g. a metal car in a grass field that has been standing in the sun for some time. The classification of the panoramas proved to be a difficult task and the final result leaves much to be desired. The classification of the Landsat 8 dataset went better and the results show a useable map. However the most interesting class in this case was the war equipment class, which cannot be validated. The heatmap could mostly be used to highlight the roads, but there are certain spots that light up and cannot be explained without field data. These spots might be interesting to check out during the expedition.","Remote Sensing; New Guinea; landsat 8; aerial photograph; Plane wrecks","en","student report","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:10275c1e-5f25-49df-ae72-77474477e50b","http://resolver.tudelft.nl/uuid:10275c1e-5f25-49df-ae72-77474477e50b","The effects of heterogeneities on the economics of thin gas column reservoirs","Grazell, Leandra (TU Delft Civil Engineering and Geosciences)","Jansen, Jan Dirk (mentor); Delft University of Technology (degree granting institution)","2018","After decades of successful exploration and exploitation of gas fields in the Netherlands, the Dutch E&P industry has accumulated a substantial portfolio of gas fields that are considered economically unviable, the so-called ‘stranded fields’. There are various reasons for a gas field to be classified as economically unviable, one of them being the small size of the field. With the current challenges the E&P sector is facing it is valuable to re-evaluate the criteria often used in determining a fields economic viability. One of those criteria is the column height encountered in the well, which when it becomes too small can be very sensitive to water inflow. Gaining further understanding of the relation between gas column height and gas production can be valuable in determining the potential of a gas field with a limited gas column. Consequently, the focus of this study is twofold: 1) finding the minimum gas column height required for producing a sufficient amount of gas (0.1 – 0.2 BCM) and 2) investigating the effect of specific important reservoir heterogeneities (i.e. high-permeability streaks and clay layers) on the production results (total gas production and production time). These two research topics were approached through two separate methods: 1) a sensitivity study carried out using two types of models, a simple box model and a complex reservoir model and 2) an analysis of gas wells, and the corresponding gas reservoirs, that encounter small gas columns. Both research methods are focused on Rotliegend gas reservoirs. The results from this study show that the minimum gas column range for yielding economic gas production was found to be 20 – 40 m, depending on the field’s characteristics and configurations. Furthermore, in the models used for this study the presence of a highpermeability streak may either cause an increase or decrease in the total gas production, however they are found to significantly reduce the production time which is beneficial towards the economic analysis of a potential project. Additionally, they are found to be highly beneficial in gas reservoirs with a low average permeability. The clay layer on the other hand, significantly increases the total gas production of the models, although this is accompanied by an increase in the total production time. A potential downside of the clay layer is the restricted flow of gas which is particularly problematic in horizontal reservoirs with a significant portion of the gas column situated below the clay layer. Lastly, a possibly positive correlation between transition zone and the total gas production from thin gas columns reservoirs was found in the well analysis, on which further investigation is recommended in order to be able to draw more meaningful conclusions.","","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:93e99447-dd46-44d6-a84e-1ace1f64b383","http://resolver.tudelft.nl/uuid:93e99447-dd46-44d6-a84e-1ace1f64b383","Quantifying the ranges of feasible control strategies for reservoir lifecycle optimization","Natarajan, Jayanth (TU Delft Civil Engineering and Geosciences)","Leeuwenburgh, Olwijn (mentor); Jansen, Jan Dirk (graduation committee); Delft University of Technology (degree granting institution)","2018","Model based optimization of reservoir water flooding is an ill-posed problem where significantly different control strategies deliver near identical Net Present Values (NPVs). Discovering and exploiting the existence of ""redundant"" control strategies - particularly those in close proximity to an optimal strategy - is valuable since this offers operational flexibility in reservoir management. To identify such 'flexible strategies' this thesis proposes a workflow to characterize the space of feasible solutions. The feasible region or feasible solution space consists of all control strategies that deliver an NPV within some threshold from an optimal value. Ensemble-based optimization is performed with strong Wolfe line search to identify an optimal control strategy. The BFGS scheme is used to iteratively approximate the Hessian matrix. One dimensional exploration is performed along the singular vector directions that characterize the null space of the Hessian. A thorough exploration results in an accurate characterization of the feasible region. Such an approach however is computationally intractable in case of realistic reservoirs with multiple hundred controls. To address this, a high-dimensional polytope is first defined using the end points from the exploration step. Subsequently, an innovative cross-section constrained maximum volume ellipsoid is inscribed within this polytope to generate an ellipsoidal approximation of the feasible region. Validation results are then presented which show that even one ellipsoid centred at the optimum control vector coordinate provides a conservative description of the feasible solution space.
The heterogeneity of layered reservoirs leads to significant variation in mechanical properties, which in turn influence fracture nucleation, fracture growth and fracture geometry. This variation in rock mechanical properties, combined with layer thickness, is called mechanical stratigraphy. Natural fractures are subject to controls imposed by mechanical stratigraphy. Focusing on the mechanisms that control natural fracture development can improve fracture characterization. As rock strength is an important part of mechanical stratigraphy, the term mechanical contrast is introduced to examine the effect of contrasts in rock strength of adjacent layers.
This study examines the effect of the mechanical contrast and confining pressure on fracture behaviour in layered rocks in the laboratory. The focus of this study is threefold, it examines the effect of mechanical contrast and confining pressure on fracture propagation, fracture orientation and fracture aperture in layered rocks.
Unconfined and confined compressive strength tests have been performed on layered samples with varying mechanical contrasts at different confining pressures. A total of 169 tests have been performed which include confined and unconfined compressive strength tests on layered and monophase samples and brazilian tensile strength tests and velocity measurements on monophase samples.
The results show that fractures initiate in the weakest layer and propagate through the layer interface or are contained within the weakest layer. Unconfined compressive strength tests showed that differences in rock strength do not always act as a containment barrier.
The combination of mechanical contrast and confining pressure does control the containment of fractures within a layer. Lower horizontal compressive stresses are required to contain fractures when the mechanical contrast increases.
Mechanical contrast does not seem to influence fracture aperture. Confining pressure however greatly influences fracture aperture as it limits the ability of fractures to dilate.
Results show that fracture orientation is controlled by mechanical contrast. Fractures refract at layer interfaces when the mechanical contrast is sufficiently high. Confining pressure does not seem to affect the refraction of fractures.
The experimental results can improve the understanding of fracture containment, fracture aperture and fracture orientation in layered rocks at subsurface conditions. The mechanical contrast of the layered rocks, combined with the stress conditions need to be considered when characterizing subsurface fractures.
Vertical connectivity between layers is of importance when predicting fluid flow through reservoirs. As frac tures often serve as preferential fluid flow paths, correctly interpreting fracture characteristics is important for successful development of layered reservoirs.","Fractures; Mechanical Stratigraphy; Confining Pressure","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:d6d83aba-3437-45d5-b099-dd5c1b287d54","http://resolver.tudelft.nl/uuid:d6d83aba-3437-45d5-b099-dd5c1b287d54","Initiation of Fault Reactivation: New Insights into the Effect of Differential Compaction","Platteeuw, Irene (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Engineering)","Vossepoel, Femke (mentor); Bertotti, Giovanni (graduation committee); Brinkgreve, Ronald (graduation committee); Hettema, Marc (graduation committee); Hoetz, G (graduation committee); Delft University of Technology (degree granting institution)","2018","The production and injection of fluids from and in reservoirs leads to changes in the in-situ stress in the subsurface. This can cause reservoir compaction, subsidence, fault reactivation and / or seismicity. As these effects may greatly influence society it is of importance to find accurate methods to describe them so they can be predicted or even better, mitigated.
This thesis discusses a new analytical approach to calculate stress in the subsurface which incorporates the effects of differential compaction on the initiation of fault reactivation. This new approach is named Differential Compaction Loading (DCL) and the reason for its development is due to discrepancies observed between calculations using the Mohr-Coulomb failure criterion, also known as Poro-elastic Loading (PEL), and field observations.
Geomechanical modelling was performed to assess fault failure sensitivity to a range of geometrical aspects as well as reservoir and fault properties. From this analysis, focusing on the reactivation pressure at which failure first occurs, an empirical sense of sensitivity was established. It was found that for the examined variations in the geometry the fault dip angle resulted in the largest spread in reactivation pressure. For the examined reservoir and fault properties, the friction angle was found to have the largest sensitivity.
With these results it was possible to improve the estimates of essential parameters within the analytical approach, yielding a better fit between analytical and modelled solutions. These solutions lie closer to field observations. Hence, the new method of DCL shows a great improvement in calculation of stresses in the subsurface, compared to the method of PEL. This calibrated analytical approach allows for a quick assessment of the fault stability within a reservoir. Additionally, through the results from the geomechanical model new insights were obtained into the way stresses change and behave when a reservoir is depleted. The rotation of the principal stresses for each level of depletion was quantified and a new definition of the critical fault angle, the dip angle which will fail first, was derived. This links the depletion pressure and related rotation angle directly to a value of the new critical fault angle when DCL is present.
Ultimately, these new insights into fault failure behaviour of boundary faults could be a useful tool in the step towards prediction and mitigation of production or injection related seismicity.
Methodology: To represent non-Newtonian behavior in the high-quality regime, the limiting water saturation for foam stability varies as superficial velocity decreases with radial distance from the well. We look at the interactions between the shock and the characteristics. The mobility control at the shock front and injectivity are examined. The system is compared to a Newtonian foam.
Results and conclusions: For shear-thinning foam, the foam front’s dimensionless velocity decreases with time, while the characteristics accelerate and collide with the shock. As the foam front propagates, the mobility ratio and mobility control becomes more favorable. The injectivity decreases until breakthrough, then improves slightly.
For shear-thickening foam, dimensionless velocity of the foam front increases with time, while the shocks slow down. Mobility control worsens and injectivity improves as the foam propagates, even before breakthrough. For extremely shear-thickening foam, the near-wellbore region exhibited shear-thinning behavior. This has three causes: a shift from the high- to the low- quality regime, the extrapolation of f mdry over a too large range, and the Namdar Zanganeh correction.
Recommendations: Future models should replace the shock with the colliding characteristic, instead of eliminating the characteristic. For shear-thickening foams, new characteristics should split off from the shock. Include the shear-thinning factor for the low-quality regime to check if the foam is still in the high-quality regime.","Non-newtonian; foam; surfactant-alternating-gas (SAG)","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:3e6a0f66-dd37-4e8b-b4a2-5c699c9c39c2","http://resolver.tudelft.nl/uuid:3e6a0f66-dd37-4e8b-b4a2-5c699c9c39c2","The impact of spatial sampling and signal-to-noise ratio on image quality in onshore seismics","Visser, Adriaan (TU Delft Applied Sciences; TU Delft Civil Engineering and Geosciences; TU Delft Mathematical Geodesy and Positioning)","Hanssen, R.F. (mentor); Dheenathayalan, P. (graduation committee); Delft University of Technology (degree granting institution)","2018","An onshore seismic survey is best conducted symmetrically, due to the reciprocity theorem of the wave field. Within the family of symmetric geometries the cross spread is most used. Recent developments show a marked increase of the number of available channels, nowadays 100,000+. This enables the use of point receivers, meaning that every geophone has its output recorded, instead of being in an array which is summed before sending the data.Geophones are ever increasing in capability, seeing an increase to lower corner frequencies and the use of batteries and GPS systems to make them cableless and suitable for point-receiver recording. MEMS are new on the market, with a noise floor of < 15 ng-per-square-root-of-Herz being available. The two main quantities which are not specified in the manufacturers’ data sheets of geophones, but which are highly relevant to the user are the noise floor and the dynamic operating range.The case study shows that most surveys nowadays are 3D cross-spread surveys with a source and receiver spacing of approximately 40m each.The most used data format in the geophysical industry is SEG-Y.A synthetic subsurface model has been generated, through which shots have been modelled. Using real field data from Saudi Aramco tests have been conducted to both increase the shot and receiver interval, and to add various amounts of noise to this data. The shots have subsequently been migrated to generate a subsurface image, for which two methods of quality control have been devised: the correlation of the image with respect to the full, no-noise model, and the number of lines as detected through the Canny edge method. The quantity spatial interval over SNR has been used to create a function for both QC methods; Corr = 117.862/( SI/SNR + 114.650), and Nl proportional to (SI/SNR)^1/4 for the number of lines. The fit for the number of lines has a very low R-squared, hence a new method must be sought for quality control.For the given model SI/SNR = 75 has been selected as a maximum for this ratio to obtain a migrated result of sufficient quality for it to be able to be interpreted.","Seismics; singal-to-noise; migration; image quality; spatial sampling","en","student report","","","","","","","","","","","","Applied Earth Sciences","Additional thesis",""
"uuid:da294cbe-7a89-46f6-b8e0-3ff0d6b8791f","http://resolver.tudelft.nl/uuid:da294cbe-7a89-46f6-b8e0-3ff0d6b8791f","A multi-scale approach for numerical modelling of the CO2 sequestration process","Alshiroofi, Duaa (TU Delft Civil Engineering & Geosciences; TU Delft Geoscience and Engineering)","Voskov, D.V. (mentor); Delft University of Technology (degree granting institution)","2017","Subsurface carbon dioxide (CO2) sequestration is a promising technology to reduce the CO2 emission into the atmosphere. After injection into subsurface formation, the carbon dioxide plume can migrate several kilometres until it is fully trapped. Four major mechanisms play an important role in trapping which include structural trapping, residual trapping, dissolution trapping or mineralization. The accurate numerical simulation of the sequestration process is challenging owing to the complexity of buoyancy driven enhanced dissolution and convective propagation of the CO2 plume. To resolve these processes, one often needs an extremely fine computational grid which makes the CPU time prohibitive for modelling at reservoir scale. Several simplified models were proposed which include analytical models (Hesse, 2008; Gasda et al., 2012), vertical equilibrium models (Gasda et al., 2012; (Pruess & Nordbotten, 2011) and an algebraic multi-scale model (Hesse, 2008). Here we proposed and applied the multi-scale models with dissolution for modelling of CO2 sequestration on the large-scale. Several numerical experiments are considered using adjusted small-scale simulation of the plume dynamic in a sloped aquifer. The enhanced rate of dissolution captured in the small-scale models with geometrical properties was then applied to the simulation in the realistic aquifer. A sink term applied at the CO2-brine-interface is implemented in the ADGPRS program. This term numerically acts as the dissolution mass transfer that would otherwise occur in a compositional simulation at fine resolution. It is important to contemplate the slow reduction in dissolution rate after the fingers begin to interact with the bottom of the reservoir. After interaction becomes significant, a reduction in the local dissolution rate is considered. We compared our multi-scale approach with a high-fidelity compositional simulation at high resolution, similar to the results presented in (Elenius, Voskov & Tchelepi, 2015). The applicability of the proposed approach was validated on the numerical model of a realistic aquifer.","CO2-sequestration; CO2-storage; multi-scale approach; saline aquifer","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:44243af2-b790-43d9-8064-248887f33722","http://resolver.tudelft.nl/uuid:44243af2-b790-43d9-8064-248887f33722","Investigation of Production of Dimethyl Ether (DME) from Renewable Resources and its Integration into the Oil Production System","Solomon, Dan (TU Delft Civil Engineering and Geosciences)","Farajzadeh, Rouhi (mentor); Bruining, Hans (mentor); Delft University of Technology (degree granting institution)","2017","Exergy investment in producing hydrocarbons is a relatively small fraction of the energy of the oil produced; yet it can reduce energy consumption in the order of percentages. In areas of high insolation or high wind speed, it can be considered that part of the exergy required for these purposes can be retrieved from sustainable energy sources. This idea is expected to be more important when applying enhanced oil recovery. As an example we use solvent (Dimethyl Ether - DME) enhanced water drive recovery. DME is a chemical solvent that has proven to be an efficient oil recovery agent. The recovered DME and oil are both considered products. The main invested exergy considered are the circulation costs of the fluids, separation/retrieval costs and the manufacturing costs of DME – it is assumed that DME is manufactured from natural gas using the single step direct method.
To improve the insight in the production process we develop a simple model of DME enriched brine injection in a 1-D reservoir. The model shows that about 92% of the oil in place is recovered using DME, which includes about 30% incremental production after water flooding. Moreover, 100% of the DME injected is recovered.
For the production /retrieval costs, we use a data set from the literature. The data set gives us the amount of DME /water injected and the amount of DME /oil/water produced. Moreover it gives the pressure drop, which allows us to calculate the power required for circulation of the fluids. Using these data, the exergy recovery factor (ExRF), which is defined as the exergy of the resources minus the exergy invested divided by the exergy of the resources produced (oil and DME) is calculated. It is observed that the ExRF initially increases with time before it declines and becomes negative. The time at which the ExRF becomes zero is called the exergy zero time. The result shows a negative exergy at the beginning of the DME enhanced water flood (DEW) process. As the incremental oil produced increases due to the presence of DME, and as more DME is back produced, which leads to less manufacturing of DME, the ExRF becomes positive. For DME enhanced recovery the initial area below exergy zero time plus the area above the exergy zero time is positive. Cumulatively, the result shows that at the end of the project, about 71% of the exergy is recovered.
The exergy analysis helps us to identify the various components that contribute the most to the exergy loss (~29%). DME manufacturing is found to be the most important contributor to the exergy loss, contributing ~80% (cumulative) to the total invested exergy. It shows that reducing the exergy of manufacturing DME increases the ExRF. The amount of DME lost in the reservoir is shown to also have an effect on the ExRF (not as much as the exergy of manufacturing DME), as it affects the utilization factor of DME. The utilization factor is the ratio of the oil produced (bbls) and the mass of DME injected. If DME is lost more DME must be injected without any increase in oil recovery and thus, DME loss reduces the ExRF.
CO2 hydrogenation is chosen as one of the innovative ways of producing DME from renewable sources. The method utilizes CO2 captured from burning the oil produced from the field in power plants and uses solar PV (photovoltaic) as the source of energy to produce H2 from water electrolysis
The results show that the CO2 captured from the power plant can be used to produce more DME than what is needed in the field. The excess DME can be reinjected or used for other purposes such as electricity generation, methanol production or for other uses e.g. as transportation fuel. It is also found that using CO2 hydrogenation has the potential to reduce greenhouse gas emissions by about 82% compared to using natural gas for DME production, which means the method is cleaner and more sustainable.","Dimethyl ether; EOR; exergy; oil; renewable energy","en","master thesis","","","","","","","","2018-12-31","","","","Applied Earth Sciences","",""
"uuid:55f31164-c84e-474a-9620-955d9aecc150","http://resolver.tudelft.nl/uuid:55f31164-c84e-474a-9620-955d9aecc150","Classifying Mangroves in Vietnam using Radar and Optical Satellite Remote Sensing: Processing Sentinel-1 and Sentinel-2 Imagery in Google Earth Engine","Portengen, Leonoor (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Remote Sensing)","Lindenbergh, Roderik (mentor); Delft University of Technology (degree granting institution)","2017","Mangroves are forest ecosystems growing in (sub)tropical saline coastal environments. With their unique root structure they serve as important natural coastal protection and provide habitats with excellent conditions for cultivating fish, shrimp and crab species. Despite all benefits mangrove forests are disappearing at alarming rates around the world but especially in Asia such as the Mekong Delta coast. Therefore, this research focusses on the Ca Mau Province in Vietnam. The Ca Mau province is the southernmost province of Vietnam with mangroves present along the coastlines, the Mui Ca Mau National Park and in mixed mangrove aquaculture farms. Remote sensing has been widely proven to be essential in mapping mangrove ecosystems. Previous research used either expensive optical and radar data sources or free but lower resolution systems. This study is the first that uses the new Copernicus Sentinel-1 radar and Sentinel-2 multispectral satellite missions that provide free available data with high spatial (10-20 meter) and temporal (10-12 days) resolution. Since optical data is prone to cloud effects and radar data is hard to interpret, both data sets are combined to investigate improvements for classifying mangroves. The data is processed in the new online Google Earth Engine platform providing a powerful tool for big data applications such as land cover classification. Optical data is found to separate mangroves by their spectral reflectance mainly in the near-infrared wavelength domain. The dominant mangrove species in the Ca Mau province, Rhizophora Apiculata and Avicennia Alba, are found to be separable from comparing unsupervised clustering results with ground truth locations. The C-band radar signal is dominated by volume scattering, indicating the density of the canopy. Especially VV-polarization has good correlation with canopy parameters. To improve information from the radar signal a temporal analysis is executed. Seasonal variations are quantified and show an increase according to the spatial succession of mangroves. Pioneer species, such as Avicennia genus, show less seasonal variations than mature species, such as Rhizophora genus. With the previous information five classes are defined: urban area, water and three mangrove classes: Rhizophora Apiculata species in extensive shrimps, Rhizophora Apiculata species in natural environment and Avicennia Alba species. A classification method is set-up in the Google Earth Engine with a Random Forest classifier using the satellite data inputs and ground truth training input of the five classes. A combination of the optical data with the temporal information of the radar data is found to be the best data input for separating those five classes. Classification results are obtained for discriminating mangrove types up to an overall accuracy of 87\%. The classification gets less reliable when mangrove species are mixed or at locations where the ground truth training input was scarce. With the resulting yearly land cover maps land cover changes can be detected. Comparing the land cover map of 2017 with a mangrove cover product of 2000 shows a regression along the southern coastline. No significant changes inside the shrimp farms are found between 2016 and 2017 but with the future availability of a long time series of Sentinel-1 and 2 data those can be detected with the method that is resulted from this study.","Mangroves; Remote Sensing; Classification; Sentinel; Vietnam; Google Earth Engine","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:10fe0b97-744f-4b3c-a1c9-f619456109a0","http://resolver.tudelft.nl/uuid:10fe0b97-744f-4b3c-a1c9-f619456109a0","Numerical Strategy for Uncertainty Quantification in Low Enthalpy Geothermal Projects","Shetty, Sanny (TU Delft Civil Engineering and Geosciences)","Voskov, Denis (mentor); Bruhn, David (mentor); Delft University of Technology (degree granting institution)","2017","In the recent years, geothermal technology has received substantial attention as an alternative source of energy. However, the lack of detailed information about subsurface formations of interest often introduces significant uncertainties to the technological and economic planning of geothermal projects. As the result, some important technological parameters, affecting geothermal projects, cannot be predicted with enough certainty. One of the most important technological characteristics in low enthalpy geothermal projects is the time when cold fluid from the injection well breaks into the production well. The large variation in thermal breakthrough time against the exact location of the well doublet was identified. These variations can largely impact the lifetime of the low enthalpy geothermal project, thereby affecting the quantification of the projects economy.
In our study, we investigate the main factors responsible for the variation of breakthrough time by performing a sensitivity analysis of different hydraulic and thermal properties. A geometry/rule-based modeling software Flumy was used to generate a detailed fluvial facies distributed, similar to that observed in the West Netherlands Basin (Nieuwerkerk Formation). The models were then populated with various thermal and hydraulic properties, correlated with the facies map. Ensembles of models were run in ADGPRS (Automatic-Differentiation General Purpose Research Simulator) to perform a sensitivity analysis.
For a given technological characteristics (distance between doublet wells, injection and production rates, drainage area etc.), a difference of approximately 50% was observed in the lifetime of the project while relocating the doublets positions and keeping the same distance between the doublet pair. The major numerical and geological factors, contributing to the difference in breakthrough time, were identified in our study. In addition, the best simulation strategy and numerical parameters for uncertainty quantification in low enthalpy geothermal projects were suggested.
Major past studies have assumed typical filtration techniques (micro-filtration) where the size of remaining dispersed particles in the water are reduced to ~2 microns. Hence, the majority of the experimental studies have used suspended particles of ~1-5 microns to investigate injectivity decline. These studies show that initially internal filter cake starts to develop and after some transition time external filter cake is formed, after which injection face is almost completely plugged. However, not many studies have been performed with ultrafiltration where remaining dispersed particle size in injection water is reduced to nano size range.
In this study, injectivity decline by ultra-filtered water injection was investigated experimentally. To mimic ultra-filtered water, spherical silica nanoparticles of 120 nm diameter were used as dispersed particles in the injected water. First, stability study of nanoparticle colloid was carried out by varying nanoparticle concentration, brine compositions and pH. Hydrodynamic size and zeta potential measurements showed that there exists a salinity and pH range in which nanoparticle colloid remain within the expected size range.
Core flood experiments were conducted on Bentheimer sandstone core plugs. Pressure measurements along the core and influent/effluent analysis were used to study the transport and retention of nanoparticles in porous media. Experimental results showed about 50 to 70 percent less injectivity decline compared to micron size suspended particles. Furthermore, results showed that external filter cake does not form by nanoparticle flow through porous media if the injection fluid’s pH and salinity are kept within a defined range obtained from stability study. Only deep bed filtration takes place where three main retention mechanisms dominate i.e. surface deposition, plugging and entrainment.
Finally, a numerical model is presented in this study that describes deep bed filtration taking into account observed retention mechanisms. Model results are found to be in good agreement with experimental results.","Formation Damage; Deep Bed Filtration; Ultra-Filtration; Nanoparticles; Porous Media; Numerical Modelling","en","master thesis","","","","","","","","2017-11-27","","","","Applied Earth Sciences","",""
"uuid:185868b6-2307-4458-a90f-bd3b5dea9e52","http://resolver.tudelft.nl/uuid:185868b6-2307-4458-a90f-bd3b5dea9e52","Prediction of stress distribution using 3D geomechanical model in De Lier Field, the Netherlands","Eddy, Muhammad Riandy (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Engineering)","Bertotti, Giovanni (mentor); Delft University of Technology (degree granting institution)","2017","An understanding about geomechanical condition is necessarily needed in order to examine the state of stress of a subsurface area. Geomechanical modeling is one of the method to understand the mechanical condition and has been used in various subsurface-related industries such as oil and gas, geothermal, and CO2 storage. The principal stress distribution influences the stress regime and dictates the creation of different type of fault and fracture. The magnitude and orientation of principal stresses are controlled by the physical and mechanical properties of the rock such as density and Poisson’s ratio. It is also effected by the tectonic stress and the geometry of the model which is created using the seismic data. In the case where the gravity is the only source of stress in the model, normal stress regime is observed in the whole depth. Meanwhile, in the case of tectonic stress is also involved, the stress regime changes over the depth from reverse, strike-slip, to normal stress regime. Lateral variation of the stress magnitude is observed even though it is not really significant. The presence of the fault in the model does not have a large contribution to influence the magnitude and orientation of the principal stresses. Changing the pore pressure magnitude is indeed can affect the principal, effective stress, and the stress regime throughout the model.","geomechanics; geology","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:aa07a9f6-1056-4eb5-85a6-5a6170dea17c","http://resolver.tudelft.nl/uuid:aa07a9f6-1056-4eb5-85a6-5a6170dea17c","Floodplain aggradation in a semi-arid endorheic basin setting, Altiplano, Bolivia","Perdomo Figueroa, Christian (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Engineering)","Donselaar, Rick (mentor); van Toorenenburg, K.A. (mentor); Delft University of Technology (degree granting institution)","2017","The importance of gas as a driver of security of energy supply and the influence of the role it currently has and will continue having in the energy transition has stimulated the development of further research studies in unconventional sources of natural gas. Mature gas fields of coarse-grained fluvial reservoirs have already reached their production plateau and are in a production decline with high-water cuts.
The northwest gas province of the Netherlands contains low-permeable fine-grained fluvial deposits of which the reservoir architecture and connectivity have not yet been widely studied using the standard industry techniques. For this reason, the geomorphological and sedimentological characteristics of the Río Colorado fluvial system were used as a modern analogue to determine how the river avulsion process has generated the current fluvial topography and why its repetition has developed a vertical stacking pattern of thin but laterally extensive layers.
Differential Global Positioning System data, Google Earth Pro Imagery, and previous studies focused on the evolution analysis of river positions in this region, allowed the observation of multiple repetitions of avulsion river in an area of approximately 400 km2, describing the fluvial sediments on top of the lacustrine deposits and representing alluvial ridges with an average width of 1500 m. Moreover, a thickness variation between the fluvial and lacustrine deposits up to 2 meters was recognised over 25 km, and a very gentle gradient slope, from 0.02° at the apex of the fluvial fan to 0.0022° in the flattened section towards the Salar de Uyuni.
Borehole data from the West Netherlands Basin and surface data from the Río Colorado were integrated to construct a three-dimensional model that represents the characteristics of the fluvial deposits regarding geobody size, geometry, and potential connectivity. With this, and the distribution of porosity and permeability as a function of channel belt and alluvial ridge width resulted in reservoir volumes up to 2×〖10〗^9 sm^3.
Six wells were simulated to understand the production behaviour in channel belts, alluvial ridges, and floodplain sediments. Water saturation, pressure and streamline maps differ from well to well, and the model contributed to quantify the most efficient production rates per well location in the fluvial fan system. The results allowed to predict the communication between facies and how that connectivity reflected the resultant flow rates and recovery factors, showing the tough gas as potential secondary targets and prolonging the production stages of mature oil fields.
From the different types of energy, heat represents a basic need in countries where the climate conditions lead to long and cold periods, namely countries at high latitudes where a big part of the produced energy is destined to household and district heating.
The Academy of Finland implemented the New Solar Community Concept project to research the development and application of alternative technologies for production and storage of energy. The use of the local geological domains has been considered as a possible solution for seasonal and long-term energy storage, specifically heat. Aalto University participates in Tackling the challenges of a Solar-Community Concept in High Latitudes by researching the seasonal storage of thermal energy in the ground simulating and assessing thermal flow for different borehole heat exchangers arrays.
To do this, numerical models have been implemented, special attention to the Weak Form Equations (WFE) and the Heat Transfer in Pipes (HTiP) models. These models are evaluated using the COSMOL® Multiphysics software, each of them with advantages and disadvantages over the other.
An in situ experiment has been performed in Aalto’s research tunnel to validate the results of the numerical models. The aim of the experiment was to assess the performance of the models based on the result comparison between the simulated and the observed data under controlled conditions.
The experiment consisted of a single U-pipe borehole heat exchanger operating under seasonal conditions. Two phases were defined, heating and cooling. In the first phase, a constant heat flux is provided to the rock by circulating a heated carrier fluid in the BHE. In the second phase, the circulation is stopped allowing the rock to cool down under normal conditions. The heat field in the rock was tracked with a monitoring borehole one meter away from the heat source. Several digital temperature sensors were installed at the monitoring point in customized equipment referred in this work as Thermal Multisensor Probes for this purpose.
The comparison made between model and observed results returned an acceptable accuracy of the predicted values of the models for the heat flow in the rock mass. Additionally, it was identified the WFE model can be improved by calibrating the borehole thermal resistance parameter in the equations, parameter that must come from experimental data. Finally, it was seen that the few discontinuities present across the boreholes had a low impact on the flow of heat through the rock for this experiment.
Currently, the tuning of the numerical models is being performed at Aalto University by increasing the weight of different parameters in the models matching the results of the experimentation process.","Borehole Heat Exchanger (BHE); numerical modelling; model validation; in situ experiment; heat flow; seasonal storage","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","Tackling the Challenges of a Solar Community Concept in High Latitudes",""
"uuid:fdb4071e-8923-4e6f-8b99-c02f833be884","http://resolver.tudelft.nl/uuid:fdb4071e-8923-4e6f-8b99-c02f833be884","3D Modeling of a foreland fold and thrust basin in the French sub-Alpine chains","Blom, Jules (TU Delft Civil Engineering and Geosciences)","Blom, Jan Kees (mentor); Bruna, Pierre-Olivier (mentor); Delft University of Technology (degree granting institution)","2017","A three-dimensional geological model has been constructed of a 49 square km area in the sub-Alpine chains in the French Drôme department. The area was situated in the Vocontian Basin, which was an epicontinental sea situated at the western margin of the Alpine Tethys Ocean, between former continents of Gondwana and Laurasia. Formations of limestones and marls have been deposited over a time span of approximately 80 Ma from the Late Jurassic to the Early Cretaceous, which can be classified into eight distinct formations. This was followed by two phases of deformation. First, the counter-clockwise rotation of Iberia into Europe inducing S-N compression in this area. Second, the collision of Adria with the European continent inducing E-W compression. Both events uplifted the area by an estimated 2500 to 3000 m.
This thesis uses data collected during the second year fieldwork (course AESB2430) of the Applied Earth Sciences bachelor at Delft University of Technology. The cross sections and geological map from this fieldwork were revised where necessary. Three new cross-sections were constructed along the north, east, and west boundaries of the area for more coverage. All cross-sections were digitized using the Move software package. To check whether these were geologically feasible, they were restored to their pre-deformation state by removing the effect of faulting and folding. These cross-sections form the basis for a 1:25 000 scale three-dimensional model. Horizon surfaces were created between cross-section horizons using spline interpolation and fault surfaces using linear interpolation
Fauld displacements are removed and an unfolding is performed on the 3D model, in an attempt to reconstruct a balanced pre-deformational setting. The result is a viable model, with some inaccuracies such as gaps and overlaps between formation surfaces and slight variation s in layer thickness. The aim of this 3D model is to aid the understanding of the configuration of rocks and of the structural evolution of the area. The average shortening due to deformation for cross-sections was found to be 14.71 %. The surface reduction value of the area is found to be 8.2 푘푚 or 14.3 %.
The direction of shortening is primarily in the S-N, due to the Iberian collision, and to lesser extent in the E-W direction, due to the Adriatic collision.","","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:15b7798a-6c22-42a3-b1b8-9052fca86c7d","http://resolver.tudelft.nl/uuid:15b7798a-6c22-42a3-b1b8-9052fca86c7d","Comparison of Multi-Model History Matching Methods","Neelakantan, Prashanth (TU Delft Civil Engineering and Geosciences)","Leeuwenburgh, Olwijn (mentor); Jansen, Jan Dirk (graduation committee); Delft University of Technology (degree granting institution)","2017","The oil industry is a high risk high reward venture. The capital and operating expenses runs into tens of millions of dollars with oil production being the primary source of revenue. During the initial development phase of the field, few wells are completed. Data collection during this period verifies assumptions made during the modelling phase and forms the basis for future development. History matching can play a significant role in these plans since it can determine uncertainties in future production.
History matching algorithms must be able to make an accurate estimates of uncertainty in future production while being computationally light. Towards this end, a number of history matching methods have been developed with emphasis being on the ensemble Kalman filter (EnKF) in recent times. While the variants of the EnKF seek to improve different aspects of the method, few have been successful in addressing all of these concerns.
The Distributed Gauss Newton (DGN) was developed with the same goal- accurate uncertainty prediction at low computational cost. It is not a variant of the EnKF but uses a sensitivity matrix determined through linear regression which decreases the computational load compared to existing gradient based techniques. In their tests, the authors report superior performance of the DGN compared to a Gauss-Newton scheme. This thesis aims to provide a detailed understanding of the method and its dependencies. This is followed up with a comparison of the DGN with an EnKF variant known as the ES-MDA.","History matching; Distributed Gauss Newton; ES-MDA","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:182be8c9-eb94-446b-94a1-269b562746d8","http://resolver.tudelft.nl/uuid:182be8c9-eb94-446b-94a1-269b562746d8","Safety and Health Comparison between European Union and United States regarding the Mining Industry","Baran, Selcuk (TU Delft Civil Engineering and Geosciences; TU Delft Mechanical, Maritime and Materials Engineering)","Keersemaker, Marco (mentor); Soleymani Shishvan, Masoud (mentor); Delft University of Technology (degree granting institution)","2017","","","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:3c24c708-1ab0-443f-bf17-84e35e0da82a","http://resolver.tudelft.nl/uuid:3c24c708-1ab0-443f-bf17-84e35e0da82a","Investigation of Vertical Cutter Mining for Increased Primary Resource Recovery and Decreased Environmental Impact: A VCM Study for De Beers, Victor Pipe, Canada","Groenewegen, Mathijs (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Engineering)","Buxton, Mike (mentor); Ngan-Tillard, Dominique (graduation committee); Vardon, Phil (graduation committee); Schwank, S.K. (graduation committee); Delft University of Technology (degree granting institution)","2017","The purpose of this thesis is to aid in the development of vertical cutting mining as a mining method. In order to do so, the technical feasibility and viability, and environmental benefit of vertical cutting as a complementary mining method were investigated. The investigation was performed for the case of the Victor Diamond mine in northern Ontario, Canada, where open pit mining ends by the end of 2018 or beginning of 2019.
Vertical cutting has been used for several decades for the construction of water retention walls in the civil engineering industry. By placing the vertical cutter system directly on top of an ore target and cutting straight, vertical trenches up to a maximum depth of 150 m, it is intended to cross over to the mining industry. Extraction with vertical cutting can occur according four extraction scenarios. Three of the scenarios are land-based, the fourth assumes flooding of the mine, and has not been considered for the Victor project.
Checkerboard mining is the base case extraction scenario with an extraction rate of approximately 30%. The long trenching scenario would increase the recovery with an additional 15% but induces a high risk of instability in the existing pit walls and the kimberlite in between the trenches. Application of backfill is the third scenario and achieves a recovery of 98%. Backfilling of the trenches requires the movement of significant volumes of additional rock as well as induces time delays due to the curing time of the backfill.
Financial evaluation of the vertical cutting scenarios shows a high dependency of the project value on a decreasing cutting performance. Cumulative cash flow analysis and NPV suggest that extending the mine life at the Victor Diamond mine with vertical cutting is favourable. Even in the case of increased rock strengths, as expected in the deeper parts of the Victor pipes, vertical cutting has a positive net present project value. Long trenching, which is considered to be of high risk for pit stability has only marginally greater project value than the base case.
The development of alternative mining solutions also aims to reduce the impact of the mining operations on the surrounding environment. Vertical cutting combines multiple mining processes into one operating piece of equipment. It reduces the GHG emissions, improves the safety of extraction process and is expected to increase the support from stakeholders. Extending operational life using conventional methods would require large expansion of the mine involving the increase of the operational fleet, pumping capacity and land usage. The application of vertical cutting has the ability to prevent the negative impact of enlarged open pit mining while maintaining the benefit of continued production.","Alternative mining; Trench cutting; Kimberlite; Residual resource recovery; Rock stability","en","master thesis","","","","","","","","2020-09-08","","","","Applied Earth Sciences","",""
"uuid:da4b998c-1d61-4dbf-be8d-49aacf116866","http://resolver.tudelft.nl/uuid:da4b998c-1d61-4dbf-be8d-49aacf116866","Effects of Thermal Shock on the Creation of Microfractures and Mechanical Properties of Various Volcanic Rock Types, including Samples from the Indonesian Geothermal Field (Tangkuban Perahu)","Imaro, Tulus (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Engineering)","Barnhoorn, Auke (mentor); Bruhn, David (mentor); Bakker, Richard (mentor); Deon, Fiorenza (mentor); Delft University of Technology (degree granting institution)","2017","This thesis aims at investigating the effect of a thermal shock of a couple of hundred degrees on the creation of the thermal microfractures and in what way the mechanical properties of volcanic rocks change. In the geothermal field, thermal microfractures can contribute to increase the permeability and produce more steam to the surface. We exposed basaltic andesite and andesite rocks from Tangkuban Perahu (Indonesia), a granite from Benin (West Africa), a basalt from the Eifel (Germany) and a basalt rock from Reynifsjara (Iceland) to temperatures of 200, 300, 400 and 500°C before cooling them rapidly by placing them in cold 20°C water. Initially, most of the sample rocks show less than 1% of porosity, excluding andesite Tangkuban Perahu (~6%) and basalt Reynisfjara (~14%), and permeability for all rocks is below detectable value (2.6 mD by Ruska gas permeameter for specified core geometry). In the geothermal field scenario, it indicates the pores were not connected and the steam may not easily flow through the rock. After the heating stage and thermal cooling, significantly increased values of porosity are observed in most of the rocks. However, only the two high porosity rocks gained permeability; the andesite Tangkuban Perahu (7-11 mD) and basalt Reynisfjara (4.45 mD). The changes in Young’s modulus, Poisson’s ratio and ultimate compressive strength of the various samples were also determined by using an unconfined Uniaxial Compressive Strength (UCS) apparatus in which both heat treated and non-heat treated samples were placed. The results show the rock strength decreases with increasing thermal shock. Similarly, we see a decrease in both Young’s modulus and Poisson’s ratio with increasing thermal shock. To recognize the thermal shock effect visually, the samples were imaged using a micro-CT scan before and after heating treatment. The resolution of the CT scanner was 30 μm at best when the whole sample is scanned. It is noticed that the porosity increases after the heating experiment. Additional mini-cores (~10 mm x 8 mm) from the whole core are also scanned at 14 μm resolution. The scans showed the porosity on the outside part of the cores is up to 10 times higher than the inner part. In Indonesia, the geothermal reservoir temperature varies from 200-300oC. By injecting cold water from the surface at a high rate, the water temperature remains low and can thus create the thermal shock that opens up existing fractures and forms new ones. In that way, it can increase fluid path ways around the well bore and along existing natural fractures.","thermal shock; microfractures; ultimate compressive strength; Young’s modulus; Poisson’s ratio; Brittleness Index (BI); micro-CT scan","en","master thesis","","","","","","","","","","","","Applied Earth Sciences","","-6.758444, 107.613694"
"uuid:11985f8c-b27d-424c-a46e-dd947a00adc2","http://resolver.tudelft.nl/uuid:11985f8c-b27d-424c-a46e-dd947a00adc2","The effect of surfactant type, velocity and permeability on CO2 foam under miscible conditions","Kagoro, Rita (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Engineering)","Farajzadeh, Rouhi (mentor); Wolf, Karl-Heinz (graduation committee); Rossen, Bill (graduation committee); Bruining, Hans (graduation committee); Kahrobaei, Siavash (graduation committee); Vincent-bonnieu, Sebastien (graduation committee); Delft University of Technology (degree granting institution)","2017","Miscible gas injection has been widely used worldwide to improve oil recovery. However, problems such as viscous fingering and gravity override undermine its success on a large scale. Foaming of the injected gas mitigates these problems by reducing the mobility of the gas.
Past studies using an ionic surfactant to foam CO2 in the presence of decane discovered the presence of three distinct regions based on the fraction of CO2 in the CO2-decane mixture namely; CO2-rich floods where the apparent viscosity increased with the increase in the CO2 molar fraction, decane-rich floods where the apparent viscosity decreased with the increase in the CO2 molar fraction and floods with intermediate CO2 molar fraction where the apparent viscosity was independent of the CO2 molar fraction in the CO2-decane mixture. The foam quality scans showed that the CO2-rich floods and decane-rich floods exhibited both low and high-quality regimes while the floods with intermediate CO2 molar fractions lacked a high-quality regime [1].This behaviour was not fully understood.
The effect of the surfactant type on the observed behaviour has been studied in this thesis by using a non-ionic surfactant in the foam quality scans. The results show the presence of the three distinct regions as observed in the previous study with an ionic surfactant. However, this study shows that the quality scans of all the CO2-decane molar compositions exhibit both the high and low-quality regimes. This study also shows that both the low and high-quality regimes are present at high flow rates. In addition, the flow behaviour is shear-thinning in nature and can be modelled by the power law.
Furthermore, the transient generation of CO2 foam in the presence of decane at different CO2-decane molar compositions has been investigated. The results show that the generation of CO2 foam in the presence of decane depends on the injected amount of CO2-decane mixture and is independent of the CO2-decane molar composition and quality.
Lastly, the effect of permeability on transient foam generation has been tested in low permeability cores and has been compared to foam generation in high permeability cores. The results show that foam generation occurs earlier in low permeability cores. In addition, the low permeability cores are susceptible to damage and blockage especially at high injection rates.
This paper evaluates the benefits of wind power for mining operations and the benefits of the Delft Offshore Turbine (DOT) type wind turbine compared to other turbines. Using the DOT type wind turbine, wind energy can be used for three different applications, namely: 1) generation of electricity, 2) direct hydraulic power and 3) direct dewatering.
Different areas in the world are then analysed on the aspects: 1) soil strength, 2) elevation or relief of the terrain and 3) the wind velocities. A case study is performed for the most suitable area in the world: Australia. Next the best-chosen location is divided into smaller regions, where the same evaluation is applied. A case study was conducted on a favourable area, calculating various cost and CO2 reduction scenarios based on simulated wind speeds.
The DOT type turbine can provide electricity, which costs 23 to 44 US$/MWh. Compared to a 1-MW diesel generator, in the best-case scenario, a wind farm generating 25 MW per hour, can save $4200/hour. Overall, implementing the DOT at the right location, can 1) remove polluting diesel generators from mining operations, 2) save energy costs up to $4200/hour and 3) reduce CO2 emissions up to 770 kilograms per MW per hour.","","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:7f80e883-936c-4abe-ac4b-2c5c15e9cb1f","http://resolver.tudelft.nl/uuid:7f80e883-936c-4abe-ac4b-2c5c15e9cb1f","The potential of advanced data analytics using machine learning to increase overall equipment effectiveness in an underground mining operation","Wansink, Jan-Douwe (TU Delft Civil Engineering & Geosciences; TU Delft Geoscience and Engineering)","Buxton, M.W.N. (mentor); Delft University of Technology (degree granting institution)","2017","Changing market dynamics make that mining companies need to increase their equipment utilization and use their equipment more effectively. The growing availability of data from mining equipment and mining operations enables the use of data analytics to achieve that goal. This thesis explores the potential of data analytics and machine learning to increase equipment utilization through the means of a case study on an underground South African diamond mine. To identify and quantify the potential of data analytics for operational improvement a benchmarking analysis of the operation was done using operational equipment effectiveness (OEE) as a measure. The outcome of this indicated that there was significant value to be unlocked if unplanned breakdowns were mitigated and unscheduled maintenance could be moved into scheduled maintenance. This led to believe that there was a solid case for breakdown prediction based on equipment sensor data using advanced analytical techniques. Data availability and quality made that the proof-of-model was initiated for one 10 ton loader with the target components for breakdown prediction being the engine, transmission and brakes. After extensive data cleaning and preparation various machine learning algorithms adopted from various non-mining disciplines were used for training predictive models. The best result was yielded using support vector machines (SVM) showing a very high accuracy (>80%) with little misclassifications. Random forests and anomaly detection were also tried but the unbalanced and noisy nature of the data made for the performance of these models not leading to satisfactory levels. The results of this modelling exercise combined with the OEE analysis give enough confidence to accept the hypothesis that there is good potential for application of advanced analytics to increase the operational effectiveness of underground mining equipment.","OEE; Operational Equipment Effectiveness; Machine Learning; Failure Prediction; Predictive Maintenance; Mining; Underground Mining; LHD; Loader; Continuous Improvement; Random Forest; Support Vector Machines; Unbalanced Data; R; SMOTE","en","master thesis","","","","","","","","2022-08-21","","","","Applied Earth Sciences","",""
"uuid:40035278-701a-4658-83fc-c061c7c04cac","http://resolver.tudelft.nl/uuid:40035278-701a-4658-83fc-c061c7c04cac","X-ray micro-CT investigation of metal recycling in egg-shaped crucibles during the Middle Iron Age","Bach, Alicia (TU Delft Civil Engineering and Geosciences; TU Delft Geoscience and Engineering)","Ngan-Tillard, Dominique (mentor); Voncken, Jack (mentor); Delft University of Technology (degree granting institution)","2017","During the extension of a sport complex near Tilburg, The Netherlands, some archeological objects were discovered. Some shreds of pottery seem to confirm that the objects found were originating from the Middle Iron Age.1 Some of the objects were egg-shaped and hollow, with a small opening on the tip. The objects did awaken the thought that they might have been used as molds for melting metal. In this report the egg-shaped crucibles, or now called ‘eggs’ are further investigated. The crucibles are examined by X-ray micro-CT scans and XRF analyses. The micro-CT scans are viewed and processed by Avizo 9.3. Results show that the eggs consist out of a half shell which is wrapped into a second shell. The second shell was still soft when wrapping, and therefore the metal scraps laid down inside the lower shell left some imprints within the outer shell. Also some highly attenuating materials can be found on the scans. This indicates the presence of metals as well as metal oxides or minerals with a high atomic number. In three eggs a large quantity of highly attenuating materials is found. In two of those eggs, these materials are seepage of metal that has been molten. In the other egg it is more likely to be a mineral, since the material is surrounding vesicles formed during the heating of the eggs. The XRF data showed that the objects are made out of clay. Some glassy looking parts on the outside of the eggs turned out to be precipitated quartz. The main metal that has been molten was found to be bronze, since high amounts of copper and tin were found.
This research first highlights the importance of the stress state and indicates which in-situ stress information is currently lacking in the Netherlands. Moreover, it is shown how stress-induced borehole features serve as basis for the determination of horizontal stress directions. The datasets used to expand the DSM database are presented, after which an extensive analysis is performed on the collected SH orientations. Subsequently, the stress magnitudes are quantified by studying the sensitivity of the in-situ stress regime to different 1D stress models. Moreover, the workflow is described for developing a 3D geomechanical model, which can serve as basis for future studies.
The research shows that the DSM database is expanded with 86 new boreholes across the Dutch on- and offshore regions. The analysis of the database indicates a dominant NW-SE SH orientation, both spatially and with depth. In most stratigraphic groups, the SH direction falls within the range of 315° ±22.5°, although a larger degree of variation is observed in the post-salt stratigraphies. On a local scale, two case studies show that SH orientations, which deviate from the regional NW-SE trend, can be related to the presence of a salt structure and a normal fault. The 1D in-situ stress models all indicate a normal faulting stress regime at reservoir depth (Rotliegend) and deeper. In the interval between the reservoir and Earth’s surface, no unambiguous stress regime is identified as the regime is more sensitive to the different boundary conditions applied.
In order to determine the feasibility of such project, a geological model for an oil reservoir was constructed, taking the Moerkapelle field as a case study, so that reservoir simulations can be performed on it and results in terms of oil production, heat production, total energy production and economics can be obtained and analyzed. Geological modelling (structural and stratigraphic) and reservoir simulation are developed in three different stages, every time making the model more complex (i.e. heterogeneity due to structural and sedimentary features).
Project feasibility was calculated in terms of the percentage of reduction on the required subsidy for a geothermal project (required subsidy is the one that makes the NPV of a geothermal project to be zero under a pre-royalty pre-tax framework). For a homogeneous reservoir the reduction in required subsidy for a single doublet geothermal project can reach 85% and complete subsidy independence can be achieved when scaling up the project to 3 or more doublets. However, for heterogeneous reservoirs, the subsidy reduction for a single doublet geothermal project would not be higher than 52% in the most optimistic case and, when all the realizations are taken into account, there is no added value from the synergy but still an average reduction in the NPV of 13%. Scaling up the project to 3 or more doublets generates an average reduction of 31% in the required subsidy with a maximum reduction of 73% in the most optimistic case.
Results show that the conductive heat transfer recharge originating from the surrounding geothermal system has a significant effect on reservoir lifetime by reducing temperatures after thermal drawdown up to 26.5% in the first test case and up to %22.6 in the second test case. In addition, it lead to an increase in the average annual thermal energy production, up to %12.5 and %14.3 respectively. The consideration of the conductive recharge from the surrounding domain shows a significantly increased lifetime estimate for low temperature geothermal reservoirs. Furthermore, permeability, rock thermal conductivity and (re-)injection temperature are the reservoir and production parameters that can greatly influence the reservoir lifetime.
The validity of the model is assessed by a comparison with an analytical model using the method of characteristics to simulate Newtonian foam flow. This model was created by A.H. Al Ayesh. From this comparison, it follows that the numerical model converges to a correct solution for sufficient fine discretizations. Finer discretizations do however introduce drawbacks, such as long computation times and high computer-memory requirements. Another drawback of the numerical model is the inevitable error that is introduced by a numerical artifact in the computation of the total relative mobility in each grid block at the front as foam advances. This error can only be reduced by even-finer discretizations.
The validity of the model for non-Newtonian foam flow simulations is not assessed directly in this thesis. But the model is expected to have similar or coarser grid-refinement criteria for shear-thinning foam flow, and finer or similar grid refinement criteria for shear-thickening foam flow.","Petroleum Engineering; Enhanced Oil Recovery; Foam; Numerical Simulation; Numerical Modelling","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:0d4f71b9-dc46-4fa3-a7f7-28c4888a38bf","http://resolver.tudelft.nl/uuid:0d4f71b9-dc46-4fa3-a7f7-28c4888a38bf","The Suitability of a High Temperature Aquifer Thermal Energy Storage on the TU-Delft Campus","Hacking, T.S.","Bloemendal, J.M. (mentor); Hellinga, C. (mentor)","2017","High temperature aquifer thermal energy storage (HT-ATES) is an energy efficient way to store heat in the subsurface, recovery efficiencies of 60-85% have been found in earlier research. The TU-Delft is step by step changing its policies into a more environmental friendly approach and a HT-ATES system could be the next step in this process by functioning as a buffer for geothermal wells. This thesis is the first step in researching if a HT-ATES system is possible on the campus of the TU-Delft. The most efficient situation for a HT-ATES system is described and based on that situation and the demand of the TU-Delft geological Formations are selected for further research. Layers are selected based on information from the DINO-loket and NLOG. The layers that are interesting and seem to be suitable for the use as a HT-ATES are a part of the Maassluis formation starting at a depth of 160 meters, the Formation of Oosterhout, the Berg sand formation at the base of the Breda formation and the Texel greensand. For the Maassluis Formation it is known that 2-3 wells are needed to ful_ll the demands. These geological formations where selected based on their general geological description or there lithological description and it looks like these geological formations can ful_ll the demands of the TU-Delft.","","en","bachelor thesis","","","","","","","","","Civil Engineering and Geosciences","Water Management","","Applied Earth Sciences","",""
"uuid:7f9726db-19a9-41fb-83fc-a06751e71dd4","http://resolver.tudelft.nl/uuid:7f9726db-19a9-41fb-83fc-a06751e71dd4","The Effects of Global Warming on a High Temperature Aquifer Thermal Energy Storage Triplet System","Schmoutziguer, Simon (TU Delft Civil Engineering and Geosciences; TU Delft Water Management)","Bloemendal, Martin (mentor); Wolf, Karl-Heinz (mentor); Delft University of Technology (degree granting institution)","2017","During the Paris climate convention, goals have been set to counter global warming and work towards a sustainable future. An energy source which has been researched more intensely the past years is HT-ATES - High Temperature Aquifer Thermal Energy Storage - system. This technique makes it possible to remove the heat pump from conventional HT-ATES energy sources and utilize waste heat or heat from sustainable sources. This paper discusses the robustness a HT-ATES triplet system. A case study is being done to test the triplet system in the present and with different climate scenarios in 2050. The triplet system consists of three storages instead of two as in conventional aquifer thermal energy storage systems. This third storage serves as a temporary storage and minimizes heat loss. With this system, the heat pump can be removed, creating a completely durable thermal energy storage system. The different scenarios show the possible effects of global warming. The system is tested in various climate scenario to see if it is robust and what the effect of global warming is on such a system will be. The results show that global warming indeed has a big impact on the functioning of a triplet system. These problems can be tackled by evaluating the climate at the location of construction of a triplet system. With this evaluation, an optimal design of the triplet system can be made. The number of solar panels and dry coolers can be optimized. Also the storage temperature inside the storages can be optimized for the present climate.","","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:0e83916e-6c7a-4bc5-a612-5a8577c1d7c9","http://resolver.tudelft.nl/uuid:0e83916e-6c7a-4bc5-a612-5a8577c1d7c9","Potential volumes of arsenic in Holocene clay plug sediments in Bihar, India","Burgers, Floortje (TU Delft Civil Engineering and Geosciences)","Donselaar, Rick (mentor); Bruining, J. (mentor); Delft University of Technology (degree granting institution)","2017","Natural occurring arsenic contamination of shallow aquifer groundwater is a problem affecting millions of people worldwide. Long term exposure to high concentrations results in severe medical conditions. On-going research into the origin and spread of the problem, risk mitigation and problem solving is of great importance. Sediment eroded and transported from mountains adsorbs arsenic (As) from river water onto its iron oxyhydroxides coatings. The geomorphology of the river is related to the concentration of As in shallow aquifers. Helicoidal flow in a meandering river leads to erosion of the cut bank in the outer bend and accumulation of sediment at the point bar in the inner bend. The result is an asymmetrical depth profile. The process of meandering and avulsion sometimes leads to the complete abandonment of a part of the river’s channel. This still-standing water body is known as an oxbow lake. Fine sediment settles from suspension and the oxbow lake gradually fills up with silt and clay. A clay plug forms, surrounding the sands of the adjacent point bar. Clay filled oxbow lakes formed by meandering rivers are high in organic content and the anoxic conditions in the hypolimnion are considered the source for the release of the adsorbed arsenic. Under reducing conditions the As is released from its solid state by microbial respiration. In the geomorphological setting of meandering rivers, abandoned channels and point bar, this process of reductive dissolution is the generally accepted release mechanism for arsenic. This research aims to provide insight in the potential arsenic volume in Holocene clay plugs in Ganges River floodplains and to present ideas on the migration processes of arsenic from clay plug to adjacent point bar. Migration of dissolved As occurs by advection and by diffusion. Satellite data from Google Earth Pro was used to simulate clay plugs with a Matlab model. The simulated data was used for the calculations of the surface area of the clay plug, the volume of the clay plug, the potential volume of As and the contact area between the clay plug and adjacent point bar. These geometric properties and concentrations of As were used to apply Fick’s first law to estimate the initial diffusion flux and the initial discharge. The surface area of the twenty selected clay plugs vary from 10! to 10! m2. The corresponding volumes are in the order of magnitude of 10! to 10! m3. The calculated As volumes range within the orders of 10! to 10! kg. The initial diffusion flux was calculated and ranges approximately between 15-300 g/m2year. For the volume calculations the exact shape of the depth profile turned out to be of little influence. For calculations of the contact area and thus the diffusion flux estimations, the true profile is crucial. In-situ sampling would provide data to minimize uncertainties and improve results.","","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:233fce59-8d66-4ac0-bbbb-a01f702fd1be","http://resolver.tudelft.nl/uuid:233fce59-8d66-4ac0-bbbb-a01f702fd1be","Two-Scale Analysis of The Dissolution of Calcite in Geothermal Sandstone Reservoirs: An Experimental and Numerical Study","Ilangovan, N.","Bruhn, D.F. (mentor); Nick, H.M. (mentor); Peksa, A.E. (mentor)","2016","Experimental studies and three dimensional finite element core scale and field scale models were used to study the effect of calcite dissolution on low-enthalpy sandstone geothermal reservoirs. A series of core flooding experiments were conducted, monitoring the porosity and permeability at 150 ◦C and 20 bars back pressure to see the effect of calcite dissolution by Glutamic acid Di-Acetic acid (GLDA). These experiments are supported by the critical salt concentration and critical fines migration velocity tests in order to ensure that any pressure variations in the core is due to the injected chelating agent and not due to other mechanical effects or chemically damaging reactions. This data obtained is then used in a core scale finite element model to obtain the corresponding kinetic and dissolution parameters. These parameters are then implemented on a field scale (homogeneous and heterogeneous) reservoir model to see the effect of calcite dissolution on the well productivity. Process based facies modelling is utilised to construct realistic heterogeneous reservoir models. In an effort to understand the effect of flow direction in the reservoir, samples were tested for the critical velocity of fines migration in three directions and it was observed that the critical velocity of fines migration in the different samples were similar, showing the homogeneous nature of the samples. From the homogeneous field scale model, for a given volume of acid injected, the effect of calcite dissolution was analysed for 5, 10, 30 and 50% calcite concentration in the reservoir. The estimated values of well productivity and equivalent permeability for 10, 30 and 50% calcite concentration were found to be in a decreasing order with 10% having the highest value. Interestingly, in the case of 5% calcite concentration the well productivity and equivalent permeability were estimated the lowest. In the case of power required by the pump the 5% calcite concentration required the highest power while the 10%, 30% and 50% were found to be in a increasing order with 10% calcite concentration requiring the least power. Although the acid penetration for the 5% calcite concentration was the furthest, the permeability improvement was too low to have a positive impact on the equivalent permeability, well productivity and power required by the pump. From the heterogeneous model, it was observed that the lifetime of the reservoir increases with increasing stimulation. This model could be used as a predictive tool for estimating the lifetime increment for a given volume of acid injected. Our simulation results show that the penetration depth (acid front) of acid is highly affected by the radial flow characteristics in field scale simulations, as the penetration depth is not linearly correlated to the volume of acid injected.","","en","master thesis","","","","","","","","2017-10-18","Civil Engineering and Geosciences","Geoscience & Engineering","","Applied Earth Sciences","",""
"uuid:ec25e33c-577c-42e9-8a81-e8a80a48890f","http://resolver.tudelft.nl/uuid:ec25e33c-577c-42e9-8a81-e8a80a48890f","A wave-equation based AVO inversion of VSP and surface seismic data","Steenhuisen, V.","Haffinger, P. (mentor); Wever, A.K.T. (mentor); Wapenaar, C.P.A. (mentor)","2016","","seismic exploration; inversion; wave-equation","en","master thesis","","","","","","","","","Civil Engineering and Geosciences","Geoscience and Engineering","","Applied Earth Sciences","",""
"uuid:0cc728b2-e0e6-419c-94e6-959780787082","http://resolver.tudelft.nl/uuid:0cc728b2-e0e6-419c-94e6-959780787082","The effect of wetting on the relative permeability behavior and oil recovery","Toutouh, Azeddine (TU Delft Civil Engineering and Geosciences)","Bruining, Hans (mentor); Delft University of Technology (degree granting institution)","2016","Oil is one of the major contributors to energy consumption. Oil reserves are expressed as the total amount of economically and technically producible oil. Total oil consumption is increasing (per capita it remains more or less the same) but it has no unambiguous influence on the remaining reserves due to new discoveries. However, increasingly sophisticated recovery methods are used to produce oil i.e. enhanced oil recovery methods. A recently proposed enhanced oil recovery method is by injection of low-salinity water in completely oil-wet reservoirs, which leads to more water-wet behavior and “consequently” to improved oil recovery.
This report will focus on the effect of wettability on the recovery efficiency. Based on the papers by Lomeland, Ebeltoft and Thomas we derive so-called LET relative permeability curves that only depend on irreducible water saturation. This is possible by using the irreducible water saturation dependence of the residual oil saturation, end point relative water permeability and the sketched behavior (Lomeland, Ebeltoft and Thomas) of the other six parameters. Admittedly this is a gross simplification, but it grasps the essence of the relative permeability behavior and makes it possible to study the recovery in terms of two parameters viz. the irreducible water saturation and viscosity ratio as opposed to eight relative permeability parameters and the viscosity ratio. High irreducible water saturation is both indicative of pore size heterogeneity and water-wet behavior. We use the theory of Buckley-Leverett to construct recovery curves for 1D and 2D displacement and various mobility (M = displacing fluid mobility / displaced fluid mobility) ratios. We solve the 1-D equations both analytically (using fractional flow theory) and numerically. For the numerical simulations in 1D and 2D we use COMSOL 5.2©. The simulations show that water-wet behavior is conducive to stable displacement, however, low recovery at breakthrough, whereas intermediate oil-wet behavior is more unstable but conducive to high ultimate recoveries. Completely oil-wet behavior leads to less stable displacement and low ultimate recoveries.","Relative Permeability; COMSOL Multiphysics; Buckley Leverett; Enhanced Oil Recovery; Wettability; Low salinity","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:0e3215fa-c290-41c1-8e13-6977b8269f6b","http://resolver.tudelft.nl/uuid:0e3215fa-c290-41c1-8e13-6977b8269f6b","CSEM component analysis: Analysing the contribution of different components to the HED response in a typical 1D VTI medium","Gebraad, L.","Slob, E.C. (mentor); Kooij, B.J. (mentor)","2016","A MATLAB program was built around 1D closed form representations of the radial electrical field in a vertical transverse isotropic (VTI) medium driven by an horizontal electric dipole (HED) in the transverse magnetic (TM) and transverse electric (TE) mode published in Andréis and MacGregor (2008). It is able to compute the contribution of the different pathways and coupling events, by mathematically decompressing the global reflection coefficients and coupling terms, while not exceeding a 1% error with Web Hosted Active-Source Modelling (WHAM) code. The program is limited to a 5 layer 1D VTI model, where source and receiver are present in the second layer seen top down. This program was used to analyse different 'airwaves' as described in various controlled-source electromagnetic (CSEM) publications. The airwaves observed include two different types of ’coupled’ airwaves; one first encountering the subsurface and subsequently the air-sea interface, the other vice versa. 3 models were analysed; deep sea – deep source-receiver setup; shallow sea–deep source-receiver setup and shallow sea– shallow source-receiver setup. Differences in the two types of airwave signals in both modes for each model are observed. The most notable difference between the two types of airwaves is increased amplitude and reduced phase shift plateauing in the shortest-pathway signal. For the shallow sea – shallow setup model, the airwaves have the same magnitude as the earth-reflected signal.","CSEM; MLCS; Horizontal Electric Dipole; Vertical Transverse Isotropic; Web Hosted Active-Source Modelling; transverse electric; transverse magnetic","en","bachelor thesis","","","","","","","","","Civil Engineering and Geosciences","Applied Geophysics and Petrophysics","","Applied Earth Sciences","",""
"uuid:48d4fb08-578b-409b-8a17-ecc8cef7394d","http://resolver.tudelft.nl/uuid:48d4fb08-578b-409b-8a17-ecc8cef7394d","Correlation and modelling of a fluvial depositional system: Outcrop analogue study of thin-bedded fluvial reservoir sandstone","van der Veer, Ella (TU Delft Civil Engineering and Geosciences)","Donselaar, Rick (mentor); van Toorenenburg, Koen (mentor); Delft University of Technology (degree granting institution)","2016","The Huesca fluvial fan contains a low gradient fluvial system with well-exposed, 3D outcrops. An outcrop study of low-sinuous deposits aims to provide a deterministic reservoir model that predicts correlation lengths, nesting and reservoir potential of thin-bedded fluvial reservoir sandstone in an overall low net-to-gross setting. To correlate the study area, centimetre accurate dGPS measurements of paleosols have been collected to calculate the tectonic dip. This was used to correlate lithostratigraphic logs of the area. Correlation lengths between wells are dependent on how spatial and continuous a paleosol has developed. Photo panels of the outcrop were analysed for net-to-gross ratio and distribution of channel and floodplain deposits. A clear distinction between high and low net-to-gross regions can be observed in the panels, which causes a lateral heterogeneity. This can be explained by the nesting of a river channel. Nesting can be caused by local avulsions triggered by crevasse splays of the river channel in combination with avulsion by annexation. The lateral heterogeneous character can have major implications on reservoir potential. The reservoir volume is dependent on the connectivity between the higher and lower net-to-gross regions. The heterogeneity also has an impact on reservoir modelling as there only is a limited subsurface expression from wells. Therefore, it cannot be known whether the higher or lower net-to-gross zones are being looked at for that particular fluvial system which makes estimates about reservoir volume difficult and inaccurate.","Geology; Fluvial; Thin-bedded Sandstones","en","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","Tough gas targeting through high-resolution geological characterization of fine-grained sedimentary rock",""
"uuid:fdc4a3c5-6e12-4afb-a596-57ef343d0ae2","http://resolver.tudelft.nl/uuid:fdc4a3c5-6e12-4afb-a596-57ef343d0ae2","Generating a full 3D Model of The Windmill (Molen de Roos)","Roebroeks, J.","Sirmacek, B. (mentor); De Graaf, M. (mentor)","2015","Merging interior and exterior laser scanning point clouds of the historical windmill, completing the missing parts from airborne laser scanning data and trying different mesh generation methods for full 3D windmill model generation in order to be able to perform virtual visits in the future.","point clouds; laser scanning; 3D model; mesh generation; point cloud alignment; AHN; TLS","en","bachelor thesis","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Remote Sensing","","Applied Earth Sciences","","52.013962, 4.351353"
"uuid:a07d9375-82f9-4d22-a562-3352a14f9e27","http://resolver.tudelft.nl/uuid:a07d9375-82f9-4d22-a562-3352a14f9e27","Assessing the potential of depleted gasfields for geothermal energy","Daarnhouwer, M.F.","Salimi, H. (mentor); Wolf, K.H.A.A. (mentor)","2013","In this thesis, the feasibility of a geothermal doublet in the former Barendrecht gas field is investigated. The aim of this work is to stay as closely as possible to the original well configuration. An IMPEXS model for the movement of the cold-water and thermal front is built to calculate the possible potential of the field. Wellbore heat losses and pump capacity were taken into account to evaluate the exergy (useful energy) created by the geothermal doublet. The results obtained by the model show that the amount of injected cold-water and consequently the amount of heat extraction from the gas field is very sensitive to the permeability of the field and the viscosity of the fluid. Inclusion of heat gain from over- and under-burden in the numerical model causes the thermal front to move slower. Since the feasibility of the project is predominantly dependent on the duration of the saturation of the field, this effect will not improve the feasibility of the project. Because only gas at a low pressure is still present in the reservoir, the field has to be saturated with cold water before production of hot water can be started. This process takes around 30 years. After that, a production rate of 5 m3/hr can be established. The temperature of the production would be 69.7 °C initially and becomes 64 °C after 500 years. When taking into account a pump that uses 100 KW to pump the water out of the formation, an exergy of 200 KW can be established. Because of the large saturation time and the limited exergy compared to other sustainable energy sources it is concluded that this project is not feasible.","geothermal energy; depleted gas fields","en","bachelor thesis","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","Applied Earth Sciences","",""
"uuid:574782a4-a72f-4d92-9fbe-21f8bc61c216","http://resolver.tudelft.nl/uuid:574782a4-a72f-4d92-9fbe-21f8bc61c216","Sedimentologisch en Stratigrafische Analyse van Vroeg Pliocene Distale Turbidieten, NW – Corfu, Griekenland","de Graaf, Peter-Paul (TU Delft Civil Engineering & Geosciences); Noordijk, Niels (TU Delft Civil Engineering & Geosciences)","Donselaar, Rick (mentor); Weltje, G.J. (mentor); Delft University of Technology (degree granting institution)","2012","","","nl","bachelor thesis","","","","","","","","","","","","Applied Earth Sciences","",""
"uuid:d10b9ac7-97b3-4a88-85aa-50c91937151b","http://resolver.tudelft.nl/uuid:d10b9ac7-97b3-4a88-85aa-50c91937151b","Interactions between beachrock formations and shoreline evolution. Case study: Togo","Rutten, G.L.","Van Paassen, L.A. (mentor)","2011","Beachrocks are lithified coastal sedimentary formations which form inside the beach body on short time scales, possibly within a year. Beachrocks can play an important role in the evolution of a shoreline as they fix the normally loose sediments. On the other hand, the evolution of a shoreline could play an important role in the genesis of beachrock and their preservation. A better understanding of these interactions will aid their use in science, to understand their genesis and to reconstruct paleo-climates. The knowledge derived is also useful for coastal engineering practice, to evaluate the response of a coastline to beachrock exposure. This study evaluated the interactions between beachrocks and shoreline evolution both from a theoretical point of view as well as in a practical case study in Togo, West Africa. In the theoretical review, the variability of shore and shoreline has been related to the diagenetic environment of a beachrock. Furthermore, existing literature was reviewed in order to assess the existing knowledge on shoreline response to the exposure of beachrock. A 2-month field campaign was carried out in Togo to gather data on beachrock characteristics and shoreline development. Finally, a synthesis was made of the theoretical findings and the results of the field campaign. The process of beachrock genesis and the controls on this process are not fully clear. Multiple mechanisms have been proposed but cannot be confirmed for all reported occurrences of beachrock. It is thus likely that no single process is responsible for the formation of beachrock. The availability of carbonate and the temperature of the beach water are likely to be among the controls on beachrock formation. It has been proposed that the stability of a beach is another control, as agitation of beach particles would not allow cementation to develop. This proposition does however not properly consider the variability of shore and shoreline. The results show that short term variations of shore and shoreline (hours to decades) are likely to be a control on beachrock genesis. The variability of the diagenetic environment related to these variations determines the cementation characteristics of beachrock. Shoreline variations thus determine the diagenetic history of a beachrock, which in turn influences the rock mass properties of the beachrock. Longer term trends in shoreline evolution are probably not linked to the genesis of beachrock, thus limiting its paleo-environmental significance. This theoretically derived conclusion needs to be confirmed by further more detailed investigation in the field. The analysis of shoreline variability related to beachrock genesis can be used to further evaluate the different mechanisms of formation that have been proposed. Analysis of weathering patterns can be the next step in increasing the paleo-environmental significance of beachrock formations. In the case study of Togo, the impact of a very large outcrop of beachrocks on shoreline evolution was investigated, by defining an approach that could be applied in similar cases. The beachrock in Togo can be divided into two formations: a main formation which shows high continuity and strength, and effectively blocks cross-shore sediment transport along major parts of the coast of Togo. Another less profound formation is found adjacent to the main formation. The beachrock in Togo fulfills a role similar to hard engineered structures which are often used in coastal engineering to protect sandy coastlines. The placement of these engineered structures in the nearshore zone triggers a certain response that is adequately understood and can be predicted using modeling software or engineering guidelines. The retreat of a sandy coastline with buried discontinuous beachrock formations poses difficult questions that have not yet been accounted for in science. The complex coupling between sediment transport and hydrodynamic conditions in the nearshore zone is not well understood, and the activation of non-erodible elements inside or as a continuous part of beaches has received only minor attention. Furthermore, beachrocks differ fundamentally from engineered hard structures as they exhibit a large natural variation in cementation characteristics and thus rock mass properties. Whereas for engineered structures the mechanical properties are known and can be used to calculate the life time of the structure, for beachrock a more thorough understanding of the genesis needs to be developed. The dominant mode of weathering of the main formation appears to be undercutting by scouring around the seaward base of the beachrock. The response of a retreating sandy coast to buried beachrock formations can be qualitatively analyzed using the Phased Retreat Model presented in this study. This model uses equilibrium shoreline profiles to determine different phases in the process of retreat. Longshore processes play a dominant role in the retreat of a coast behind a beachrock barrier. Starting from locations where the beachrock barrier has been breached, erosion landward of the beachrock travels in the opposite direction of the longshore current seaward of the beachrock. The Phased Retreat Model can be used to further analyze and predict shoreline development along the coast of Togo. Using a more data-driven analysis and by investing in structural solutions. the Togolese government can upgrade their shoreline protection policy to the philosophy of Integrated Coastal Zone Management. Furthermore, the presented model could be used in similar cases elsewhere. Lastly, the Togo case can be used for further generic research on morphodynamic response to barriers in the near-shore zone.","beachrock; coastal geomorphology; togo; bight of benin; coastal erosion","en","master thesis","","","","","","","","2012-03-14","Civil Engineering and Geosciences","Geotechnology","","Applied Earth Sciences","",""
"uuid:4b55a197-88bb-43fe-99a6-50ba56a58514","http://resolver.tudelft.nl/uuid:4b55a197-88bb-43fe-99a6-50ba56a58514","El Niño and satellite altimetry: Observation of large-scale waves on the Pacific Ocean","Brink, Wilbert","Schrama, E.O. (mentor); Klees, R. (mentor)","1999","De meest recente El Niño, die van 1997-98, was een van de hevigste gedetecteerde ooit en beïnvloedde het weer op globale schaal. In Zuid-Amerika waren de gevolgen bijna niet te overzien. Hevige regenbuien veroorzaakten onder meer modderstromen, die duizenden huizen vernielde, honderden bruggen en het leven kostte aan maar liefst 2100 mensen. Sinds een paar jaar weet men meer over het ontstaan van El Niño. Eens in de 3 tot 7 jaar, draaien de passaatwinden om naar het oosten en zorgen ervoor wat warm oppervlaktewater naar de kust van Zuid-Amerika wordt geblazen. Als een zogenaamde Kelvingolf beweegt dit water langs de evenaar naar het oosten. Daar aangekomen kunnen Kelvin golven omgebogen worden naar het noorden en het zuiden, om op hogere breedten westwaartse golven te creëren. Deze Rossby-golven bewegen met een breedteafhankelijke snelheid. Altimetrie-satellieten als TOPEX/Poseidon en ERS-2 kunnen relatieve zeehoogten meten met een precisie van enkele centimeters en zijn daarom uitermate geschikt om Kelvin en Rossby golven te visualiseren. Eerst moeten er nog wel enkele atmosferische en instrumentele correcties gedaan worden en moet er gecorrigeerd worden voor de geoïdehoogte en het tij. Metingen worden in een bepaalde baan verricht, die voor beide satellieten overigens nogal verschilt, zodat eigenlijk maar naar een kleine gedeelte van het zeeoppervlak echt gemeten wordt. Er moet dus geïnterpoleerd worden, waarvoor in deze scriptie een methode wordt voorgedragen die gebruikt maakt van variogrammen. Een zoek-radius van 4º met daarin een exponentiele gewichtsfunctie blijkt geschikt te zijn voor de ruimtelijke interpolatie. De gewichten van metingen op verschillende tijdstippen zijn gelijk. Met deze interpolatiemethoden kunnen zeehoogte-kaarten gemaakt worden, met rastercellen van 1º bij 1º. Het gemiddelde zeeniveau kan nog van de zeehoogten afgetrokken worden, omdat hier alleen de temporele verschillen van de zeetopografie interessant zijn. Dit heeft als bijkomend voordeel dat de relatief onbekende geoïde geëlimineerd wordt. Door de verschillende zeehoogtekaarten te combineren, kunnen er tijdlengtediagrammen gemaakt worden. Hierin zijn de Kelvin en Rossby golven te zien als evenwijdige lijnen. De helling van zo’n lijn is een maat voor de snelheid van de betreffende golf. Klimatologische verschijnselen hebben vaak een jaarlijks effect op de zeetopografie, wat weer storend kan werken op de lengte-structuren in de tijd-lengtediagrammen. Deze jaarlijkse trend is daarom geschat, door een sinus-functie met een periode van een jaar te fitten op de zeehoogte-data. De amplitude van de jaarlijkse cyclus is in sommige gebieden meer dan 10 cm. Radon-transformaties zijn een handige gereedschap om de helling – en dus de snelheid -van de lengte-structuren in de tijd-lengtediagrammen te detecteren. Het is gebaseerd op het integreren van lijnen met alle mogelijke posities en hellingen die er zijn, wat in het geval van een enkele lijn leidt tot een maximum in het Radon domein. The gevonden snelheden van de Kelvin golven komen goed overeen met theorieën, de Rossby-golfsnelheden zijn duidelijk te hoog. Een aanpassing van de theorieën die het meest waarschijnlijk is, is het feit dat er een soort gemiddelde stroming, die westwaarts gericht is, de Rossby-golven iets versnelt. Ook blijkt zeebodemtopografie – en met name onderzeese ruggen - de Rossby-golven te kunnen versterken en versnellen. Er is geen duidelijk verschil tussen TOPEX/Poseidon snelheden of ERS-2 snelheden, hoewel ERS-2 wel iets meer ruis laat zien in de tijd-lengtediagrammen. Door de tijd-lengtediagrammen te combineren zijn reflecties van equatoriale Kelvin en van Rossby golven waar te nemen. Kelvin golven wekken bijna altijd Rossby golven op in het oosten van de Pacific, maar ook vice versa in het westen. De grootschalige golven op de oceaan lijken daarom in een gekoppeld systeem te zitten, dat gecombineerd met winddraaiingen en – uitbarstingen een grote oorzaak van El Niño kan zijn.","TOPEX/Poseidon, ERS-2, El Niño, remote sensing","en","master thesis","","","","","","","","","Civil Engineering and Geosciences","Physical, Geometrical and Space Geodesy","","Applied Earth Sciences","",""
"uuid:f781bd24-371d-4f94-a9a2-2a05eab3a9ee","http://resolver.tudelft.nl/uuid:f781bd24-371d-4f94-a9a2-2a05eab3a9ee","El Niño and satellite altimetry: Observation of large-scale waves on the Pacific Ocean","Brink, Wilbert","Schrama, E.O. (mentor); Klees, R. (mentor)","1999","De meest recente El Niño, die van 1997-98, was een van de hevigste gedetecteerde ooit en beïnvloedde het weer op globale schaal. In Zuid-Amerika waren de gevolgen bijna niet te overzien. Hevige regenbuien veroorzaakten onder meer modderstromen, die duizenden huizen vernielde, honderden bruggen en het leven kostte aan maar liefst 2100 mensen. Sinds een paar jaar weet men meer over het ontstaan van El Niño. Eens in de 3 tot 7 jaar, draaien de passaatwinden om naar het oosten en zorgen ervoor wat warm oppervlaktewater naar de kust van Zuid-Amerika wordt geblazen. Als een zogenaamde Kelvingolf beweegt dit water langs de evenaar naar het oosten. Daar aangekomen kunnen Kelvin golven omgebogen worden naar het noorden en het zuiden, om op hogere breedten westwaartse golven te creëren. Deze Rossby-golven bewegen met een breedteafhankelijke snelheid. Altimetrie-satellieten als TOPEX/Poseidon en ERS-2 kunnen relatieve zeehoogten meten met een precisie van enkele centimeters en zijn daarom uitermate geschikt om Kelvin en Rossby golven te visualiseren. Eerst moeten er nog wel enkele atmosferische en instrumentele correcties gedaan worden en moet er gecorrigeerd worden voor de geoïdehoogte en het tij. Metingen worden in een bepaalde baan verricht, die voor beide satellieten overigens nogal verschilt, zodat eigenlijk maar naar een kleine gedeelte van het zeeoppervlak echt gemeten wordt. Er moet dus geïnterpoleerd worden, waarvoor in deze scriptie een methode wordt voorgedragen die gebruikt maakt van variogrammen. Een zoek-radius van 4º met daarin een exponentiele gewichtsfunctie blijkt geschikt te zijn voor de ruimtelijke interpolatie. De gewichten van metingen op verschillende tijdstippen zijn gelijk. Met deze interpolatiemethoden kunnen zeehoogte-kaarten gemaakt worden, met rastercellen van 1º bij 1º. Het gemiddelde zeeniveau kan nog van de zeehoogten afgetrokken worden, omdat hier alleen de temporele verschillen van de zeetopografie interessant zijn. Dit heeft als bijkomend voordeel dat de relatief onbekende geoïde geëlimineerd wordt. Door de verschillende zeehoogtekaarten te combineren, kunnen er tijdlengtediagrammen gemaakt worden. Hierin zijn de Kelvin en Rossby golven te zien als evenwijdige lijnen. De helling van zo’n lijn is een maat voor de snelheid van de betreffende golf. Klimatologische verschijnselen hebben vaak een jaarlijks effect op de zeetopografie, wat weer storend kan werken op de lengte-structuren in de tijd-lengtediagrammen. Deze jaarlijkse trend is daarom geschat, door een sinus-functie met een periode van een jaar te fitten op de zeehoogte-data. De amplitude van de jaarlijkse cyclus is in sommige gebieden meer dan 10 cm. Radon-transformaties zijn een handige gereedschap om de helling – en dus de snelheid -van de lengte-structuren in de tijd-lengtediagrammen te detecteren. Het is gebaseerd op het integreren van lijnen met alle mogelijke posities en hellingen die er zijn, wat in het geval van een enkele lijn leidt tot een maximum in het Radon domein. The gevonden snelheden van de Kelvin golven komen goed overeen met theorieën, de Rossby-golfsnelheden zijn duidelijk te hoog. Een aanpassing van de theorieën die het meest waarschijnlijk is, is het feit dat er een soort gemiddelde stroming, die westwaarts gericht is, de Rossby-golven iets versnelt. Ook blijkt zeebodemtopografie – en met name onderzeese ruggen - de Rossby-golven te kunnen versterken en versnellen. Er is geen duidelijk verschil tussen TOPEX/Poseidon snelheden of ERS-2 snelheden, hoewel ERS-2 wel iets meer ruis laat zien in de tijd-lengtediagrammen. Door de tijd-lengtediagrammen te combineren zijn reflecties van equatoriale Kelvin en van Rossby golven waar te nemen. Kelvin golven wekken bijna altijd Rossby golven op in het oosten van de Pacific, maar ook vice versa in het westen. De grootschalige golven op de oceaan lijken daarom in een gekoppeld systeem te zitten, dat gecombineerd met winddraaiingen en – uitbarstingen een grote oorzaak van El Niño kan zijn.","TOPEX/Poseidon, ERS-2, El Niño, remote sensing","en","master thesis","","","","","","","","","Civil Engineering and Geosciences","Physical, Geometrical and Space Geodesy","","Applied Earth Sciences","",""