Evaluating an adequate computer model representing the characteristics of a subsurface reservoir is of great importance in the oil and gas industry. With recent data acquisition developments, high-resolution geological models can be generated for the subsurface reservoirs; however, uncertainties of geological data and too many details in the model have brought up remarkable limitations for application of high-fidelity geo-models in reservoir management. To generate efficient low-resolution models, which are relatively representative of the reservoir dynamic behaviour, data-driven models are proposed. The data-driven models are trained principally based on the production history of the reservoir with primary knowledge of structural information. The Data-driven Discrete Well Affinity (DiWA) model is designed to generate efficient proxy models that require basic geological information and full production history of the reservoir. Since it benefits the computational power of the Delft Advanced Terra Simulator (DARTS) and adjoint gradient-based optimization, the DiWA model has become an efficient framework in terms of accuracy and computational costs. This research shows that the DiWA model can relatively reconstruct the reference reservoir parameters out of an ensemble of priors, and the final results can be improved utilizing closer prior knowledge to the true response. Additionally, it is demonstrated that the performance of the DiWA model in a complex, realistic oil field can be enhanced using a comprehensive objective function, applying appropriate well controls, understanding the underlying driving mechanisms, using sufficient degrees of freedom, and applying consistent boundary conditions.

Mechanical dredging of a stiff clay results in clay lumps. Those clay lumps can be reused for the construction of land reclamation projects, and hereby economic and environmental value is generated. Placement of the clay lumps in water result in a matrix of clay lumps and an interlump void space. The collapse of the interlump void space will cause large settlements and needs to be overcome before the site can be used for construction. Preloading is an effective method to close the interlump voids. Stiff clays soften over time due to unloading and swelling. As a result, the strength and stiffness of the clay lumps decrease over time. The presence of discontinuities accelerates the softening process. It was proposed by Leung et al. (2001) that the interlump void space closes under a reduced preload of 25 kPa. The interlump void space closes under a reduced preload because the lumps soften over time. The question rises if closure occurs within a normal construction timespan, i.e., 1 - 2 years, under this reduced preload. In this study, a combined experimental and numerical approach is applied to determine the influence of soil characteristics, softening and the presence of discontinuities on interlump void closure. The influence of softening due to chemical and hydro-mechanical swelling is tested by experimental swell-load tests on stiff overconsolidated Boom clay samples. Additionally, the presence of discontinuities is studied by CT images, and a miniature clay fill test is performed to study the softening time and the rearrangement effect. Furthermore, a numerical study is performed in which the influence of specific soil characteristics on void closure was researched by a sensitivity analysis. By the experimental tests, it is shown that a pore water chemistry change alters the degree of swelling and its compressibility. Furthermore, fissures were identified in the sample material by CT images. The smallest microfissures could not be identified due to the resolution of the images. Consequently, it is impossible to estimate the effect of fissures on the hydraulic conductivity. Therefore, literature data was used to estimate the hydraulic conductivity and this was used as the input in the calculations. In the numerical study, it was shown that MPM could model the softening behaviour over time. The sensitivity analysis showed that the MPM model responds consistently to parameter sensitivity analyses. This leads to the conclusion that MPM can be used as a investigation tool to increase the understanding of the influence of parameter variability on the final interlump void closure problem. The resulting strains of the numerical model comply with the theoretically calculated strains. It was expected that the numerical strains were smaller than the experimentally determined strains, due to the presence of interlump voids in the numerical model. But, the numerical strains are larger than the experimental strains. In the sensitivity analysis, it was found that the final strains and closure time are highly dependant on the soil characteristics. It is likely that the input of the MPM model differs compared to the true sample material and thus different strains result. The time until the interlump void space closes was determined by a simplified geometry in MPM under a preload of 25 kPa. For an unfissured Boom clay, interlump closure takes place after approximately 16 years while for a fissured Boom clay it only takes 2 months. Thus, closure of the highly simplified geometry takes place within a normal construction timespan for a fissured Boom clay. It must be kept in mind that the results are highly dependant on the geometry, lump size and soil characteristics. Therefore, these results can not be generalized into an estimate of the interlump void closure time for any stiff lumpy clay fill. In conclusion, the feasibility of MPM was explored and it turned out to be a promising method to model the interlump void closure problem. Further studies are required to check if the model gives plausible results for more advanced constitutive soil models and geometries. If the results are positive, MPM can be used as a investigation tool to increase the understanding of the interlump void closure time for more refined geometries.

Geological surveying is a common practice performed by geologists nowadays. Determining layer orientation parameters and identifying folds are examples of features needed in order to create a geological map or model of the (sub) surface. Surveying is expensive and time consuming, therefore such survey is recently being investigated and implemented in 3D point clouds. This thesis provides a method to quickly obtain geological information such as orientation parameters and fold information in a semi-automated manner. Obtaining this parameters is currently still a difficult problem because of data density and calculation complexity. Fast and reliable are terms important for the created method. Large point clouds can easily jam a system and reliability is important for usability and compatibility of the created results. A method is designed which can handle bulk data, performing operations such as filtering and noise reduction assisting in data handling. Next to general calculations such as roughness filtering, intensity filtering and directional filtering of generated normals, the use of a Graphical User Interface (GUI) greatly improves the reliability of the feature calculations. The user selects areas which are potentially interesting for acquiring layer orientation information, which are then analyzed by the method itself creating a base for determining the layer orientation parameters. This base is then used to attempt the reconstruction of the bedding layers of the geological outcrop resulting in the desired geological features. The method has been tested on the “La Charce” dataset and the “Meso-scaled fold” dataset for method validation and on the “Pradelle 2” dataset for compatibility checking. Average calculation time is with approximately 10 minutes reasonable fast. The acquired dip direction of approximately 156 degrees is very similar to that of Prentice (2017), Bisschop (2017) and the fieldwork teams of 2016. The dip angle of 52 degrees is on the other hand off compared to validation results. The layer thickness calculations are comparable, all theses show that the bulk thicknesses between ~30 and ~70 cm. The fold dataset has no validation results but the images look good. It has to be mentioned that all results obtain commission and omission errors but these are in no comparison to the results which are correct.

Growing interest has been expressed the last decades regarding the Late Cenozoic, gas-bearing sediments of Southern North Sea Basin. Comprising the shallow subsurface of the Dutch offshore sector, these sediments have been deposited by Eridanos fluvio-deltaic system, draining the Fennoscandian and Baltic shield through the present Baltic Sea. Three successful producing fields - A12-FA (2007), F02a-B-Pliocene (2009) and B13-FA (2011)- and five under development have triggered the conduction of several studies in the offshore area. However the deltaic environment has been characterized as highly complex owing to its influence by the onset of Northern Hemisphere Glaciation and thus the processes that governed the system have not become entirely understood. Enhanced cooling followed by the waxing and waning of the glaciers during warmer periods had an immediate impact on sediment supply, accommodation space and mineralogical input. Although the sediments have been studied in terms of chrono-biostratigraphy, no systematic investigation with respect to the three main aforementioned factors as well as the regional sequence stratigraphy and its link to the reservoir deposits has been made up to date. Therefore, this study employed sequence stratigraphy as a method to examine Eridanos conditions of deposition, investigate the interplay between accommodation space and sediment supply and explore the nature of the gas-bearing reservoir sediments. The adopted methodology is comprised of two basic pillars, observation and interpretation. The first records as clearly as possible the observations arise from the sequence analysis while the second extracts the meaningful information and interprets it in terms of temporal and spatial concepts. Using 2D seismic and well log data the basic observations were the stratal terminations, stacking patterns, seismic facies and the shoreline trajectory. Seismic and well log interpretation showed that the delta experienced multiple events of sea level fall which forced the shoreline to regress basinward and caused sediment erosion or non-deposition. These events are bounded by nine time-significant surfaces of subaerial unconformities which constitute the depositional sequences. Normal regression comprised the dominant depositional trend, combined with aggrading-prograding patterns, leading to characteristic alternations of highstand and lowstand system tracts. Three main depositional environments which correspond to open marine turbidites (submarine lobes), delta front and delta top were identified from well logs, core descriptions and the seismic facies analysis. The study suggests that the shallow gas is located in the alternations of silty-sandstones and claystones of the delta plain which comprise the vertical stacking of parasequence topsets within the highstand- lowstand system tracts. Reconstruction of the relative sea level changes and sedimentation rates was made based on a technique introduced by this study. It uses the average thickness of each seismic unit in order to interpolate time between the three known absolute ages obtained by the literature. The graphs showed that the accommodation space was generated by a low rate of sea level rise while sedimentation rates were increasing over time. However the scarcity of time constrains in combination with the uncertainty in the estimation of seismic volumes resulted in a low resolution outcome. A comparison between the findings of this study and those of the existing literature was made. The overall depositional trends and conditions seem to be in accordance with the other surveys. Nonetheless the proposed interplay between accommodation and supply can be assigned as local since the examined area is limited compare to areas studied in literature. Limitations are traced in the quality of the 2D seismic data hampering the observation regarding the relation between the reflectors and the surfaces. Consequently, the study offers an insight into the conditions under which the gas-bearing deltaic sediments were deposited and tries to place them in the established sequence stratigraphic framework. Also it provides information regarding the distribution of the deltaic environments and identification of the reservoir rocks within each setting. The resulting interpretation can be used for prediction of the reservoir formations since the genetically-related packages where they were identified are distributed in a predictable manner within a sedimentary basin.

Every year the second years of the bachelor Applied Earth Science have a geological fieldwork in Southern France. To supervise the students after a day in the field the idea is to collect a 3D model database of the outcrops in the field. This is done by photogrammetry and the open-source program MicMac. In this report an acquisition protocol and an automatic method for processing the images is developed. Students only need to collect images of their outcrop (following the given acquisition method) and upload them to the server. Some test cases are tested in this report and these results are given. The written workflow works on most test cases, except test cases made with a drone. The problems which arose were the right scale of the 3D models and sparse data at the boundaries of the outcrops. Although the workflow works in most cases, there are several adjustments to do in the future, like to make it more robust, find a method to create the right scales and to display all 3D models in one map.

Alluvial stratigraphy is influenced by both allogenic and autogenic factors, which are difficult to be distinguished from each other because they operate at overlapping spatial and temporal scales. Moreover, it remains uncertain whether autogenic dynamics can result in sedimentary cyclicity that resembles allogenically-driven stratigraphic products. In order to undertake this challenge and address the uncertainty, we first test what sedimentary processes can produce the alluvial cyclicity observed in outcrops by designing comparable scenarios in the process-based numerical modelling. In the meantime, we systematically characterize floodplain aggradation cycles by tracing them in a UAV-based photogrammetric model. Moreover, we comprehensively describe channelized sandstone bodies in the field and the model to reconstruct the paleogeography. Lastly, we configure the relationships between floodplain aggradation cycles and sandstone bodies of different river styles, based on which we identify the link between orbital forcing and alluvial stratigraphic response.@en

Alluvial deposits in the subsurface are essential for geo-energy production and storage in many regions worldwide. Accurate correlation and characterisation of alluvial stratigraphy requires an understanding of how river channels were spatially deposited, and which geomorphological processes acted upon them. This doctoral dissertation the potential of orbital forced cyclic climate control on fluvial systems and its application to reservoir characterisation and subsurface correlation. It discusses the correlation between cyclic arrangements of floodplain strata and corresponding sandstone occurrence based on an analogue outcrop study. Subsequently the methods and concepts are applied on two subsurface case studies where correlation and characterisation of the reservoir is attempted. @en

The rising demand for clean energy has drawn the attention for more geological research to low enthalpy geothermal applications in the Netherlands. A multi-scale reservoir characterization is carried out with the aim to understand the geothermal reservoir potential of the Triassic Main Buntsandstein (RBM) in the Tilburg area. Seismic data, well logs and petrophysical data are used to evaluate the reservoir architecture, stratigraphy, and quality of the potential Main Buntsandstein geothermal aquifer. It was found that the study area is located within a horst- and graben system bounded by normal faults where the top boundary of the RBM is located at depths of 1900 – 2100 m for the horsts and 3300 – 3500 m for the grabens. The horsts and grabens range from circa 3000 to 4000 meters in width. Well log correlations and thickness maps at RBM scale suggest thicknesses of the Subgroup from ca. 160 to 220 meter. The thickness of the Main Buntsandstein generally decreases on the horsts and increases towards the grabens, suggesting higher temperatures of up to 100° C and thicker sand units in the grabens. Thickness generally decreases on the horsts and increases towards the graben suggesting faults were active at time of deposition and better geothermal potential in the grabens due to greater depths and thicker RBM unit. The core analysis of the study showed that the potential Main Buntsandstein reservoir is composed of a variation of sand- and mudstones interlayers, which were deposited on a large fluvial-fan system terminating in a playa-lake environment towards the basin center. Four different facies associations were distinguished within the cores of wells AND-06, KWK-01, SPC-01 and WWN-01-S2. Optimal reservoir connectivity is, according to the facies architecture model, expected in the Lower Volpriehausen and Detfurth Sandstone Members due to the presence of stacked amalgamated fluvial fan sandstone facies. It appeared that aquifer quality does not correlate with increasing depth or stratigraphic position, although the Volpriehausen- and Detfurth Claystone Members display significant poorer reservoir properties. These members, which can be correlated at well distance due to its widespread deposition as playa-lake sediments, are likely to act as a baffle to flow in the subsurface. Best reservoir potential, considering petrophysical measurements on porosity and permeability, is within the fluvial fan sandstones of all facies associations whereas the fine grained cross bedded sandstones show best reservoir quality of all encountered lithofacies. The data showed highly variable measurements where highest mean values for the porosity (11 %) and permeability (105 mD) are encountered in the Lower Detfurth Sandstone Member of well HVB-01. It turned out that northern located wells of Tilburg (AND-06, KWK-01, WWN-01-S2 and SPC-01) showed considerable poor reservoir potential with mean values of below 10% and 10 mD for the porosity and permeability. The southern wells, however, appear to have generally higher reservoir properties compared to the northern wells suggesting better geothermal potential in the area south of Tilburg.

In 1990, the 44/21a-6 well was drilled in the Southern North Sea. Core material was taken from the Westphalian A/B part of the core. Some of this core material was recently obtained by the TU Delft via the North Sea Core Initiative. Since the Westphalian A/B in the Pennine Basin is fluvio-deltaic in origin, it is highly variable both vertically and laterally. In this thesis we set out to develop a method to extrapolate facies found in the core material to recognize if these are present in other locations in the well. This means that core material is correlated to the well log. This correlation is then extended over the rest of the well. Two investigation targets were chosen, the first facies is channel base facies, consisting of very coarse sandstone, the second a swamp facies. This firstly requires a detailed core log, and a short study of the well log data. The core log is interpreted in order to try to establish some form of elektrofacies. The well data is then formatted and different principal component analyses (PCA’s) are performed in order to differentiate the facies from their surroundings. For both analyses more than 90% of the variance was explained by the first two component axes, making them reliable. Both target facies require different data sets in order to distinguish them from their surroundings. The swamp facies becomes easily visible from the third principal component axis, while the channel base sand is harder to differentiate, being recognizable from a point cloud in a principal component plot. In total 40 coals were found to be present over the researched well interval, starting underneath the Zechstein formation, from 12800 to 13800 ft. No other similar channel base coarse sands were found over the interval apart from the one in the cored material. Overall, it seems that the basics for this method of detection and extrapolation is quite reliable and better than using the original log data, although it does need some further development and improvement.

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.