Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"Fracture aperture"”.
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Volume change behavior of clay soils and the effect on discrete fractures
This study examines the behavior of subsurface fractures in fine-grained soil such as clays in response to changing environmental conditions. Fractures serve as conduits for moisture transfer, which can lead to substantial shrinking and swelling of the surrounding fracture boundary soils. These …
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Multiphase flow and fault poromechanics : understanding earthquake triggering and seismic hazard
… a first contribution at the scale of individual fractures, we study the impact of confining stress on the capillary pressure behavior during drainage through rough fractures, where we find that capillary pressure variations are sensitive to the degree of confining stress and the degree of spatial …
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Investigation of changes in permeability due to poro-thermo-elastic effects in enhanced geothermal reservoirs
… data is utilized to generate the subsurface fracture map of three formations. For this purpose, a geological structure is reconstructed according to its past tectonic history. Then fractures are stochastically simulated using Gaussian simulation. After generating the subsurface fracture map, …
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Geomechanical behaviour and deformation of coal mine roof strata around faults: toward an engineering geological model
… zone shows heterogeneous rock mass properties. A fracture aperture-spacing analysis was undertaken in varying proximity to faults, and the fracture aperture-size scaling laws apparently replicate power-law relationships identified in other studies. However, it was found power-law equations of …
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Experimental Investigations on Flow and Mass Transport in Stressed Rough Fractures
The study of flow and transport in rough, fractured media is essential in the development of new energy technologies including enhanced geothermal systems, EGS, and CO2 sequestration. This is a complex problem, mostly due to the number of interacting physical processes in the fractured environment. …
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Thermomechanical analysis of rock asperity in fractures of enhanced geothermal systems
… returns to the surface through production well. Fracture provides the primary conduit for fluid flow and heat transfer in natural rock. Fracture is propped by fracture roughness with varying heights which is called asperity. The stability of asperity determines fracture aperture and hence imposes …
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Investigation of Recrosslinkable Preformed Particle Gels for Natural Gas Conformance Control
… for mature reservoirs with conduits or fractures. Two RPPG systems were used for the experiment: a CO<sub>2</sub>- resistant RPPG (CR-RPPG) synthesized using acrylamide (AM) and 2-acrylamide-2- methylpropane sulfonate acid (AMPS), designed for CO2 flooding; and an acrylamide-co-acrylic …
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Fracture Growth Kinematics in Tight Sandstone Reservoirs
Opening-mode fractures—joints and veins—are widespread structures in sedimentary rocks even in slightly deformed and flat-lying sequences. Understanding the growth and connectivity of fractures in low permeability sandstone reservoirs is essential for optimal hydrocarbon exploitation. In a linear …
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Implications of Permeability Uncertainty During Three-phase CO2 Flow in a Basalt Fracture Network
… on the behavior of CO₂ as it leaks through fractures characteristic of the flow interior, particularly at conditions near the critical point for CO₂. In this study, a two-dimensional 5 × 5 m model of a fracture network is built based on high-resolution LiDAR scans of a Columbia River Basalt …
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Fracture Modeling and Flow Behavior in Shale Gas Reservoirs Using Discrete Fracture Networks
Fluid flow process in fractured reservoirs is controlled primarily by the connectivity of fractures. The presence of fractures in these reservoirs significantly affects the mechanism of fluid flow. They have led to problems in the reservoir which results in early water breakthroughs, reduced …
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Analytical and Numerical Modelling of Thermal Conductive Heating in Fractured Rock
… site remediation. Modelling was conducted in a fractured bedrock environment containing a system of parallel, equally-spaced horizontal fractures. A semi-analytical solution to the two-dimensional heat conduction equation was developed and used to study temperature distributions between two …
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The role of accessory minerals in inhibiting bentonite erosion in the geological disposal of higher activity radioactive waste
… loss assessments. As indeed is the presence of fracture aperture variability on the extrusion / erosion process, as almost exclusively, research carried out to date has been in uniform aperture fracture flow cells. Four month duration erosion experiments were undertaken, designed to mimic …
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Structural and stratigraphic controls on fracture distribution within sand bodies of the Upper Iles and Lower Williams Fork formations, Mamm Creek and Divide Creek fields, Piceance Basin, Colorado
… of hydrocarbons requires the presence of fractures, either natural fractures or induced fractures from hydraulic stimulation. Natural fractures have been documented to significantly enhance reservoir permeability. This thesis examines the stratigraphic and structural controls on fracture …
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Particle swarms in confining geometries
… transport is complicated by the presence of fractures and fracture networks which govern the paths that particles will be able to take. In this thesis, subsurface particle transport will be investigated using particle swarms; collections of hydro-dynamically interacting particles which …
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An experimental study on characterization of physical properties of ultramafic rocks and controls on evolution of fracture permeability during serpentinization at hydrothermal conditions
… Each core had a well-mated through-going tensile fracture, to investigate evolution of fracture permeability during serpentinization. The samples were tested in a triaxial loading machine at an effective pressure of 30 MPa, and temperature of 260°C, simulating a depth of 2 km under hydrostatic …
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Simulating water tracer test in naturally fractured reservoirs using discrete fracture and dual porosity models
A naturally fractured reservoir (NFR) is a reservoir with a connected network of fractures created by natural processes such as diastrophism and volume shrinkage (Ordonez et al. 2001). There are two models to simulate this kind of reservoirs: the discrete fracture model and the dual porosity model. …
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Fluid-Driven Fractures in Elastic Hydrogels: Propagation and Coalescence
… a novel experimental exploration of fluid-driven fractures in a brittle hydrogel matrix. Fluid-driven fracturing is a procedure by which a fracture is initiated and propagates due to pressure applied by a fluid introduced inside the fracture. We describe how to construct the experimental setup …
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Coupled geomechanics and transient multiphase flow at fracture-matrix interface in tight reservoirs.
Fractured hydrocarbon reservoirs play a significant role in the world economy and energy markets. Fluid injection (normally water) forces the hydrocarbons out of the reservoirs. Geomechanics, externally applied stress on the rock, play a significant role in the oil recovery from fractured …
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Investigating the Evolution of Rock Discontinuity Asperity Degradation and Void Space Morphology under Direct Shear
… shear and how this degradation influences the aperture distribution. Although prior studies have attempted to investigate asperity failure mechanisms, they have been hampered by the lack of appropriate visualization and modelling tools. In particular, until recently it was not possible to …
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Characterization of anisotropy in organic-rich shales: shear and tensile failure, wave velocity, matrix and fracture permeability
Lamination and fractures are common features in organic-rich shales. The objective of this thesis is to determine the impact of lamination and fractures on elastic properties, shear and tensile failures, and the permeability of organic-rich shales. The elastic properties of rocks determine the …
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