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 24 for “"Horizontal Stress"”.
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The Role of Horizontal Stress in the Formation of Valley Stress Relief Features in Flat-Lying Sedimentary Rocks
… evidence supporting the existence of a regional horizontal stress, well in excess of gravitational considerations, will is presented. This evidence will include a database of in situ measurements so that an estimate of the magnitude of this stress can be obtained for the analysis to follow. …
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Orientation of the maximum horizontal stress (SHmax) in the Orange basin and Outeniqua sub-basins of South Africa : neotectonic implications
… are preferentially-aligned to the contemporary stress field. Expanding the catalogue of stress data for the region is therefore vital to better understand the regional stress field pattern and aid in identifying potentially seismogenic structures. In these intraplate regions, reliable …
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Analysis of the variation of horizontal stresses and strains in bedded deposits in the eastern and Midwestern United States
The variation of the horizontal stress magnitude in bedded deposits in the eastern and Midwestern United States is analyzed with respect to the site depth and the rock elastic modulus using data from 40 sites. For the development of adequate regression models with the elastic modulus, zones with …
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Multiscale determination of in situ stress and fracture properties in reservoirs
… we address the problem of determining in situ stress and fracture properties in reservoirs using borehole logs and surface seismic reflection data. The dissertation covers four subtopics. The first is the determination of horizontal stress magnitudes from measurements in a borehole. Two types …
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PRELIMINARY EXPERIMENTAL AND MODELING STUDY OF PRESSURE DEPENDENT PERMEABILITY FOR INDONESIAN COALBED METHANE RESERVOIRS
… pressure resulted in significant decrease in horizontal stress and increased permeability. The permeability increase at low reservoir pressure was significant, a positive finding for Indonesian coals. Using the measured volumetric changes with variations in pressure, the cleat compressibility …
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Effect of in-situ stresses on the stability of coal mine development workings
… coal mining, those related to in-situ stresses are the most common ones affecting the safety of a mining operation. As a result, this has been the focus of many ground control research works done in the recent years. More work has been done in this thesis to add additional information …
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Spatio-temporal microseismic analysis of the Woodford Shale, Canadian County, Oklahoma
… this ellipsoid can be related to local in-situ horizontal stress ratios. These methods are applied to surface microseismic data collected for six horizontal wells drilled and completed in the Woodford Shale in Canadian County, Oklahoma. Additionally, an attempt is made to bridge the gap between …
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Performance of a propped retaining wall at the CTRL, Ashford
… from a spade cell aligned to measure vertical stress with the estimated<br/>overburden acting on it as the overburden was excavated. This study adds significantly to<br/>the previous data as spade cells have not previously been \lsed in the Atherfield Clay, and<br/>the performance of spade …
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LABORATORY INVESTIGATION OF COAL PERMEABILITY UNDER REPLICATED IN SITU STRESS REGIME
… parameter impacted by changes in effective stress and desorption-induced "matrix shrinkage". Most commonly-used theoretical models developed to predict CBM production as a result of permeability changes are based on the assumption that the deformation of a depleting coalbed is limited to the …
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Development and evaluation of an instrumentation system for high acceleration centrifuge testing of an artificial rock material
… testing of an artificial rock material.</p> <p>A stress analysis of the centrifuge rotor was performed to ensure its safe operation. The centrifuge was found to be safe for operation to a maximum of 1000 rpm for a payload of 15 pounds (6.82 kg).</p> <p>The instrumentation system developed includes …
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Imaging the Soultz Enhanced Geothermal Reservoir using double-difference tomography and microseismic data
… structure which lines up with the maximum horizontal stress orientation. Lastly, we show that using the double-difference tomographic method to relocate events produces locations that come close to rivaling those of collapsing methods.
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Structural analysis of brittle deformation features along Grenvillian shear zones in southeastern Ontario
… among joint and fault orientations and maximum-horizontal stress directions associated with major tectonic events suggest a history of repeated stages of deformation along the CMBbtz and RLmz. Neoproterozoic-Cambrian opening of the Iapetus Ocean is interpreted to have produced NNE-striking …
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Synthetic geomechanical logs and distributions for marcellus shale
… contribution of mechanical properties (Principal stress profiles) of shale to hydraulic fracturing strategies is a well-understood concept. It may also contribute to better, more accurate simulation models of production from shale gas reservoirs.;In this study, synthetic Geomechanical logs …
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Shear Wave Splitting Analyses in West Texas
… Basin in West Texas to understand crustal stress and induced seismicity. The selected events of ML2.0 are recorded by the TexNet and USArray/Transportable Array (TA) stations. SWS parameters, the fast polarization direction and the delay time, are computed using a semi-automatic algorithm. …
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Characterization of anisotropy in organic-rich shales: shear and tensile failure, wave velocity, matrix and fracture permeability
… At the well scale, the estimation of the minimum horizontal stress in Eagle Ford shale was improved by including the effect of lamination in Eagle Ford shale and the characterization of a bentonite layer at the boundary of upper and lower Eagle Ford shale with high Poisson's ratio. Breakout is …
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Geomechanical behaviour and deformation of coal mine roof strata around faults: toward an engineering geological model
… was undertaken, and compared with in situ stress field and local-scale measurements of joint and cleat at two sites. Results indicate that a range of faulting styles including normal and reverse faulting are prevalent across the mine, with the dominant discontinuities in the target …
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The effects of fault-induced stress anisotropy on fracturing, folding and sill emplacement: Insights from the Bowie coal mines, southern Piceance basin, western Colorado.
<p>The recognition of fault-perturbed stress fields is an important tool in areas of mineral or hydrocarbon exploration. The Bowie underground coal mines of western Colorado expose a reverse-reactivated growth fault that perturbed the stress field during cleat (fracture) formation, rotating cleat …
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ESTIMATION OF DIFFERENT COAL COMPRESSIBILITIES OF COALBED METHANE RESERVOIRS UNDER REPLICATED IN SITU CONDITION
… in pore pressure under replicated in situ stress/strain conditions was measured. The results showed that decreasing pore pressure resulted in a significant decrease in horizontal stress and increased permeability. The permeability increased non-linearly with decreasing pore pressure, with a …
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Borehole Breakouts in Transversely Isotropic Posidonia Shale
… in unconventional shales, we investigate stress-induced irregular extensions of the borehole diameter, which are also referred to as borehole breakouts. For this purpose, experiments with different borehole diameters, bedding plane angles and stress boundary conditions were performed on …
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