"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:a334e1fa-08bd-470f-bf05-6ab8a0145056","http://resolver.tudelft.nl/uuid:a334e1fa-08bd-470f-bf05-6ab8a0145056","Mechanical Factors Controlling the Development of Orthogonal and Nested Fracture Network Geometries","Boersma, Q.D. (TU Delft Applied Geology); Hardebol, N.J. (TU Delft Applied Geology); Barnhoorn, A. (TU Delft Applied Geophysics and Petrophysics); Bertotti, G. (TU Delft Applied Geology)","","2018","Orthogonal fracture networks form an arrangement of open well-connected fractures which have perpendicular abutment angles and sometimes show topological relations by which fracture sets abut against each other, thus forming a nested network. Previous modelling studies have shown that orthogonal fractures may be caused by a local stress perturbation rather than a rotation in remote stresses. In this study, we expand on the implications of these local stress perturbations using a static finite element approach. The derived stress field is examined to assess the development of implemented microfractures. The results show that the continuous infill of fractures leads to a gradual decrease in the local tensile stresses and strain energies, and, therefore, results in the development of a saturated network, at which further fracture placement is inhibit. The geometry of this fully developed network is dependent on the remote effective stresses and partly on the material properties. Saturated networks range from: (1) a set of closely spaced parallel fractures; (2) a ladder-like geometry; and (3) an interconnected nested arrangement. Finally, we show that our modelling results at which we apply effective tension, are equivalent to having a uniformly distributed internal pore fluid pressure, when assuming static steady state conditions and no dynamic fluid behaviour.","Nested arrangement; Opening mode fracturing; Orthogonal network; Pore pressure; Subcritical crack growth","en","journal article","","","","","","","","","","","Applied Geology","","",""
"uuid:298b9ef8-7f21-47eb-8a32-8f0f811203d9","http://resolver.tudelft.nl/uuid:298b9ef8-7f21-47eb-8a32-8f0f811203d9","Fluid flow from matrix to fractures in Early Jurassic shales","Houben, M. E. (Universiteit Utrecht); Hardebol, N.J. (TU Delft Applied Geology); Barnhoorn, A. (TU Delft Applied Geophysics and Petrophysics); Boersma, Q.D. (TU Delft Applied Geology; Universiteit Utrecht); Carone, A. (Universiteit Utrecht); Liu, Y. (Universiteit Utrecht); de Winter, D. A.M. (Universiteit Utrecht); Peach, C. J. (Universiteit Utrecht); Drury, M. R. (Universiteit Utrecht)","","2017","The potential of shale reservoirs for gas extraction is largely determined by the permeability of the rock. Typical pore diameters in shales range from the μm down to the nm scale. The permeability of shale reservoirs is a function of the interconnectivity between the pore space and the natural fracture network present. We have measured the permeability of the Whitby Mudstone, the exposed counterpart of the Posidonia Shales buried in the Dutch subsurface and a possible target for unconventional gas, using different methods and established a correlation with the microstructures and pore networks present down to the nanometer scale. Whitby Mudstone is a clay rich rock with a low porosity. The permeability of the Whitby Mudstone is in the range of 10−18m2–10−21m2. 2D microstructures of the Whitby Mudstone show no connected pore networks, but isolated pore bodies mainly situated in the clay matrix, whereas 3D data shows that connected pore networks are present in less compacted parts of the rock. A closely spaced interconnected fracture network is often required to speed up transport of fluids from the matrix into a producing well. For fluids within the matrix the nearest natural fracture is on average at a distance of approximately 10cm in the Whitby Mudstone. The combination of the permeability data and the porosity data with natural fracture spacing of the fractures present in outcrops along the Yorkshire coast (UK) resulted in new insights into possible fluid pathways from reservoir to well.","Fracture network; Jurassic shales; Multi-scale flow; Permeability; Whitby Mudstone","en","journal article","","","","","","","","","","","Applied Geology","","",""
"uuid:cea9f985-5ec6-4ac4-9f62-fef3d31ccb99","http://resolver.tudelft.nl/uuid:cea9f985-5ec6-4ac4-9f62-fef3d31ccb99","2-D to 3-D Fracture Network Detection and Forecasting in a Carbonate Reservoir Analogue Using Multiple Point Statistics (MPS)","Bruna, P.B.R. (TU Delft Applied Geology); Hardebol, N.J. (TU Delft Applied Geology); Bisdom, Kevin (Shell Global Solutions International B.V.); Straubhaar, Julien (Université de Neuchâtel); Mariéthoz, Grégoire (University of Lausanne); Bertotti, G. (TU Delft Applied Geology)","","2017","","","en","abstract","","","","","","","","","","","Applied Geology","","",""
"uuid:e046cd22-5898-49d7-9b83-26e4ebc9494e","http://resolver.tudelft.nl/uuid:e046cd22-5898-49d7-9b83-26e4ebc9494e","Signature of seismic wave attenuation during fracture network formation","Barnhoorn, A.; Zhubayev, A.; Houben, M.; Hardebol, N.J.; Smeulders, D.M.J.","","2015","","","en","journal article","European Geophysical Abstracts (EGU)","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""
"uuid:c36391cf-63a2-4f9e-b786-2b11d9b9af4e","http://resolver.tudelft.nl/uuid:c36391cf-63a2-4f9e-b786-2b11d9b9af4e","Fracture-fault networks and role of nested Topology on the mechanical response and Connectivity for tight gas extraction","Hardebol, N.J.; Bertotti, G.","","2014","Our aim is to quantify the role of intermediate length scale pre-existing faults and fractures on the critical loading of first order faults and on the potential for enhancement of fracture network. The arrangement of smaller scale natural fractures relative to larger-scale faults is subject of our combined outcrop and numerical modelling study. In this study we perform finite element geomechanical simulation to quantify mechanical response in terms of loading and failure of complex network of pre-existing fault and fracture planes. The first and intermediate order faults and fractures are included in the mechanical models by means of Discrete Surface Networks. The structural configuration of the Dutch SE North Sea P6 block inspired the definition of the first order faults of our geologic input model for mechanical simulations. The analyses of first and smaller order fault patterns of the North Sea subsurface case were combined with the detailed fracture observations from our outcrop analogue. Differently from previous studies, this work addresses the length scales between larger scale tectonic models that account mainly for the horst-bounding faults and the detailed studies that address stresses at and around boreholes.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""
"uuid:2b303824-e0ba-44f3-b518-51a5ae6456be","http://resolver.tudelft.nl/uuid:2b303824-e0ba-44f3-b518-51a5ae6456be","Quantifying rock's structural fabric: A multi-scale hierarchical approach to natural fracture systems and stochastic modelling","Hardebol, N.J.; Bertotti, G.; Weltje, G.J.","","2014","","","en","journal article","EGU","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""
"uuid:9d8057f0-2d94-40ff-97f3-6a6795f2f074","http://resolver.tudelft.nl/uuid:9d8057f0-2d94-40ff-97f3-6a6795f2f074","Outcrops as analog of fractured reservoirs: Capture explicit geometries, derive statistics and model behaviour","Hardebol, N.J.; Bertotti, G.","","2014","Adapted from extended abstract prepared in conjunction with oral presentation at AAPG Hedberg Conference.","","en","conference paper","AAPG","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""
"uuid:294e71c1-c816-4d09-9f7f-c59ef2ab03f5","http://resolver.tudelft.nl/uuid:294e71c1-c816-4d09-9f7f-c59ef2ab03f5","A Geologically Consistent Permeability Model of Fractured Folded Carbonate Reservoirs: Lessons from Outcropping Analogue","Bisdom, K.; Bertotti, G.; Gauthier, B.D.M.; Hardebol, N.J.","","2013","Presently adopted fracture-related permeability models of large folded reservoirs are simplistic and often unrelated to the geological setting and evolution of the considered structure. In order to improve predictions of fluid flow in more complex subsurface fractured reservoirs, we build a 3D fracture network model of an outcropping fold in Tunisia, and populate different structural domains with fracture data, collected from outcrops. Within the studied fold, we find large variations in deformation mechanisms between different formations, with the main mechanisms being Layer Parallel Shortening (LPS), resulting in regional deformation, and the more localized impact of fiber stresses and flexural slip. Within the steep flank of the anticline, we find that in one formation fracturing is mostly controlled by fiber stresses, whereas in the underlying formation flexural slip is the main deformation mechanism. These two formations are separated by a detachment surface. Using stress and strain fields, we aim at reconstructing the conditions at which these fractures have been formed. This can provide a better understanding of the relation between fracture patterns in different structural domains of a fold and the stress evolution that formed these fractures, and the subsequent impact of different fracture patterns on fluid flow in fractured folds.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""
"uuid:03ae967d-36b3-4756-874e-6e779d7a7835","http://resolver.tudelft.nl/uuid:03ae967d-36b3-4756-874e-6e779d7a7835","Predicting multiscale fracture patterns in buried reservoirs: The importance of outcrop data in a coherent workflow","Bertotti, G.; Hardebol, N.J.; Bisdom, K.","","2013","Fracture data from outcropping analogs are often acquired but rarely used to improve permeability predictions in buried reservoirs. To improve this we present a systematic workflow which includes i) the building of a geometric model of the investigated structure, ii) the execution of mechanical simulations to determine state of stress and strain field, iii) the use of outcrop data to populate the model and iv) develop a reservoir-scale permeability model. To make full use of outcrop data, we present new acquisition and processing tools allowing able to provide a full characterization of the fracture field even when fractures are not bed-confined. A few case studies are presented to discuss this workflow in sedimentologically and structurally heterogeneous settings.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""
"uuid:5ad8d83d-c877-4b61-a928-643767642b63","http://resolver.tudelft.nl/uuid:5ad8d83d-c877-4b61-a928-643767642b63","Quantifying Fracture Heterogeneity in Different Domains of Folded Carbonate Rocks to Improve Fractured Reservoir Analog Fluid Flow Models","Bisdom, K.; Bertotti, G.; Gauthier, B.D.M.; Hardebol, N.J.","","2013","Fluid flow in carbonate reservoirs is largely controlled by multiscale fracture networks. Significant variations of fracture network porosity and permeability are caused by the 3D heterogeneity of the fracture network characteristics, such as intensity, orientation and size. Characterizing fracture network heterogeneity is therefore essential in order to understand and predict fluid flow in fractured reservoirs, but this cannot be accomplished using only 1D data from wells, which is usually the only type of data available from the subsurface. To extend the 1D data to 3D data we commonly analyze the regional deformation, as different types of fold mechanisms produce different deformation styles and subsequent fracture patterns. 2D outcrop studies of fractures are often used to quantify these multi-scale relations between fracturing and large-scale structures. We build a geometric model, then make a mechanical analysis, followed by populating the fracture domains with outcrop-derived information. We use a novel approach called Digifract, which allows us to collect large amounts of 2D fracture data from outcrops, including fracture size, orientation and spacing measurements. Using this method we accurately quantify the links between multi-scale deformations, from fractures to regional tectonics. We applied the Digifract method in the outermost foothills of the Southern Tunisian Atlas, analysing fractures in different domains of four external folds with simple geometries and deformation histories. The lithology of the outcropping cores of all anticlines consists of the same fractured carbonates. The dimensions of the folds are on the same scale as reservoir analogs and form analogs for reservoirs in the Ghadames/Illizi basin, covering parts of Algeria, Tunisia and Libya. We relate differences in fracture characteristics to different localities (e.g., far or close to fold axes) and different folding stages in order to derive general rules that can be applied to subsurface fold analogs.","","en","conference paper","AAPG","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""
"uuid:d28badb9-2797-42ee-bb0f-0c3bd72fee3f","http://resolver.tudelft.nl/uuid:d28badb9-2797-42ee-bb0f-0c3bd72fee3f","Small-scale convection at a continental back-arc to craton transition: Application to the southern Canadian Cordillera","Hardebol, N.J.; Pysklywec, R.N.; Stephenson, R.","","2012","A step in the depth of the lithosphere base, associated with lateral variations in the upper mantle temperature structure, can trigger mantle flow that is referred to as edge-driven convection. This paper aims at outlining the implications of such edge-driven flow at a lateral temperature transition from a hot and thin to a cold and thick lithosphere of a continental back-arc. This configuration finds application in the southern Canadian Cordillera, where a hot and thin back-arc is adjacent to the cold and thick North American Craton. A series of geodynamical models tested the thermodynamical behavior of the lithosphere and upper mantle induced by a step in lithosphere thickness. The mantle flow patterns, thickness and heat flow evolution of the lithosphere, and surface topography are examined. We find that the lateral temperature transition shifts cratonward due to the vigorous edge-driven mantle flow that erodes the craton edge, unless the craton has a distinct high viscosity mantle lithosphere. The mantle lithosphere viscosity structure determines the impact of edge-driven flow on crustal deformation and surface heat flow; a dry olivine rheology for the craton prevents the edge from migrating and supports a persistent surface heat flow contrast. These phenomena are well illustrated at the transition from the hot Canadian Cordillera to craton that is supported by a rheological change and that coincides with a lateral change in surface heat flow. Fast seismic wave velocities observed in the upper mantle cratonward of the step can be explained as downwellings induced by the edge-driven flow.","","en","journal article","American Geophysical Union","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""