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Reservoir characterization of the Haynesville Shale, Panola County, Texas using rock physics modeling and partial stack seismic inversionCoyle, Sarah Bryson 27 October 2014 (has links)
This thesis investigates the relationship between elastic properties and rock properties of the Haynesville Shale using rock physics modeling, simultaneous seismic inversion, and grid searching. A workflow is developed in which a rock physics model is built and calibrated to well data in the Haynesville Shale and then applied to 3D seismic inversion data to predict porosity and mineralogy away from the borehole locations. The rock physics model describes the relationship between porosity, mineral composition, pore shape, and elastic stiffness using the anisotropic differential effective medium model. The calibrated rock physics model is used to generate a modeling space representing a range of mineral compositions and porosities with a calibrated mean pore shape. The model space is grid searched using objective functions to select a range of models that describe the inverted P-impedance, S-impedance, and density volumes. The selected models provide a range of possible rock properties (porosity and mineral composition) and an estimate of uncertainty. The mineral properties were mapped in three dimensions within the area of interest using this modeling technique and inversion workflow. This map of mineral content and porosity can be interpreted to predict the best areas for hydraulic fracturing. / text
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Investigating the Performance Of Electrical Resistivity ArraysPerren, Lee John 11 October 2005 (has links)
2D inversion modeling of synthetic data is used to evaluate the performance of five electrical resistivity arrays, with the primary criteria being the reproduction of sharp model boundaries. 2D synthetic noise free data were calculated simulating a modern fixed spacing multi-electrode cable. Twelve 2D synthetic models, resembling a number of different geologic situations, were used to investigate performance of the dipole-dipole, pole-dipole, pole-pole, Wenner and Schlumberger arrays
Although the synthetic, noise-free data were well matched for all inversions, many of the inversion results exhibit substantial mismatches from the true model. The greatest resistivity mismatches are near model discontinuities. Resistivity mismatches become worse with depth and the geometry of geologic boundaries in the deep portion of the models are not well reproduced by any of the arrays. Field surveys must be designed so that the geologic target is in the middle of the data constrained region. Different arrays performed best for different models and a practical table is presented allowing the practitioner to choose the optimal array for the particular geologic situation under investigation. Although the dipole-dipole and pole-dipole arrays may not be the optimal array for a given geology, they rarely fail for any model, and thus are recommended for reconnaissance or preliminary investigations in regions of unknown geology.
Contrary to traditional advice found in textbooks, based on 1D profiling and sounding, and data plot comparison, this study, using 2D data and 2D inversion, finds the Wenner and Schlumberger arrays, thought to perform poorly for vertical boundaries, performed well for a vertical boundary and a thin vertical resistor. Similarly, the dipole-dipole and pole-dipole arrays, thought to perform poorly for horizontal and dipping boundaries, performed well for several models containing those geometries. Another interesting finding is that changing the polarity of geologic units from resistors to conductors changed relative array performance in most models. / Master of Science
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