Most available data from shale production zones tends to point towards the presence of complex hydraulic fracture networks, especially in the Barnett and Marcellus formations. Representing these complex hydraulic fracture networks in reservoir simulators while incorporating the geo-mechanical parameters and fracture apertures is a challenge. In our work we developed a fracture to production simulation workflow using complex hydraulic fracture propagation model and a commercial reservoir simulator. The workflow was applied and validated using geological, stimulation and production data from the Marcellus shale. For validation, we used published data from a 5200 ft. long horizontal well drilled in the lower Marcellus. There were 14 fracturing stages with micro-seismic data and an available production history of 9 months. Complex hydraulic fractures simulations provided the fracture network geometry and aperture distributions as the output, which were up-scaled to grid block porosity and permeability values and imported into a reservoir model for production simulation and history match. The approach of using large grid blocks with conductivity adjustment to represent hydraulic fractures in a reservoir simulator which has been employed in this workflow was validated by comparing with published numerical and analytical solutions. Our results for history match were found to be in reasonable agreement with published results. The incorporation of apertures, complexity and geo-mechanics into reservoir models through this workflow reduces uncertainty in reservoir simulation of shale plays and leads to more realistic production forecasting. The workflow was utilized to study the effect of fracture conductivity damage on production. Homogenous and heterogeneous damage cases were considered. Capillary pressures, determined using empirical relationships and experimental data, were studied using the fracture to production workflow. Assuming homogenous instead of heterogeneous permeability damage in reservoir simulations was shown to have a significant impact on production forecasting, overestimating production by 70% or more over the course of two years. Capillary pressure however was less significant and ignoring capillary pressure in damaged hydraulic fractures led to only 3% difference in production in even the most damaged cases. / text

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The North American landscape changed tremendously following the arrival of European settlers. Before European arrival, New England’s landscape was primarily forested. As Europeans moved inland from the eastern seaboard, they cleared the forest for settlement and agricultural use. Eventually the Industrial Revolution made a different kind of mark on the landscape. Starting in the late 1790s, the textile mill industry developed throughout the region. Mills were located along swift moving rivers, which later produced power when dams were created along them. Following the early 1900s mill production decreased, leading to the abandonment of many mills and their adjacent dammed mill ponds. However, the environmental changes wrought by the mill ponds still exist in New England’s landscape. Large volumes of fine sediment have since built up in some of these former mill ponds and concerns about the sediment and water quality have become widespread. Today many former textile mill rivers throughout the U.S and Europe have been tested in an attempt to determine current contamination levels and to apply appropriate strategies if necessary to reduce pollutants to acceptable levels. Little is known about water and sediment quality of the former mill ponds in Scituate, Rhode Island. This research sought to address this problem by conducting trace metal testing of two mill ponds in the Scituate River Watershed: Peabody Pond and Jordon Pond. Results revealed that both ponds contain pollutants from present and past sources, but that contemporary land use practices may be the most harmful to water and sediment quality. Existing mill metal piping left on the landscape and present-day motorways and urban runoff contain large quantities of suspended solids such as copper, lead and zinc with lead showing the highest concentration levels of all metals tested. This research demonstrates that our past landscape activities, specifically New England’s historic textile production, still influences present environmental conditions, and that as human activities on the landscape change, so do threats to environmental quality.

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This dissertation investigate to determine the presence of biological nitrogen fixation in two reservoirs in the southwestern United States: Lake Arlington and Lake Ray Hubbard.

<p>This Master Thesis work aims to find a model system combining the positive effects of surfactant and polymer flooding to enhance oil recovery. This report presents the results of 12 core floors performed to enhance recovery of waterflood residual oil. The recovery is enhanced by a visous surfactant flood consistent of one polymer to increase the viscosity, one surfactant for interfacial tension reduction, and one di-alcohol to function as co-surfactant and for salinity control.</p><p>The chemical treatment that gave the best result, gave an additional oil production normalized on OOIP of 20%, improving the oil recovery from 45 to 66% mostly by the means of mobility control. Pure viscosity floods gave an additional recovery of 12 to 13% of OOIP.</p><p>Novel technology is used to investigate environmental friendly enhanced oil recovery. A biopolymer made out of microfibrils from wooden material was for the first time ever to my knowledge, attempted used in a core flood to enhance oil recovery.</p><p>A viscous surfactant tertiary recovery process may help improve oil recoveries from many marginal oil fields or those that face shut-down due to uneconomic operating costs, but still contain significant amounts of oil. </p>

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

The further exploration and development of Pabst Gas Field with faulted sand reservoirs require an understanding of the properties and roles of faults, particularly Low Throw near Vertical Faults (LTNVFs), in gas migration and accumulation at a reservoir scale. This study presents numerical modeling of gas migration and accumulation processes in Pabst Field. Based on studies of the reservoirs, structure, faults, and fluid properties of the field, reservoir scale modeling was performed to determine the gas supply style and the fault properties by means of hundreds of iterations in which the fault properties and gas supply pattern were modified to match the gas distribution obtained from modeling with the gas distribution inferred from seismic data constrained by well data and production data. This study finds that in the main three sand reservoirs of Pabst Field the overlying younger sands cut down into the underlying older sands, so that partial connections between the three sands allow gas communication among the sands. Meanwhile, three fault families break up the three sands into numerous compartments. A primary fault and large synthetic and antithetic faults act as gas migration pathways: the synthetic and antithetic faults are inlets for gas flow and the primary fault is an outlet, and LTNVFs act as barriers to gas flow. Modeling requires fault properties in the field to change while the field is formed. The porosity and permeability of the faults in Pabst Field are 10% and 0.1 md, respectively, during gas charging of the sand reservoirs. But when there is no gas charging and large gas columns are maintained, the porosity and permeability of the faults decrease to 6% and 0.001 md, respectively. Pabst Field probably has an impulse gas charge history. Fault opening and closing, gas charge and recharge, and replacement of gas by formation water may occur. A combination of stratigraphy, structure, overpressure and gas charge rate control gas migration style, gas charge history, and gas distribution in the field. The significance of the study is that this improved numerical approach for modeling gas migration into and through specifically faulted sand reservoirs fills the gap between basin modeling and production modeling.

The Jacob field was discovered in the year 1931. In the year 2002, due to the low productivity of the field, the company wanted to determine whether to keep operating, abandon or sell the field. So they asked Texas A&M University to perform the study, determine the oil potential, and make recommendations to improve production. Since no previous reservoir study was performed in this field, the original oil in place and the current status of depletion was unknown. Therefore a complete integrated study was needed in order to learn about the reservoir and evaluate it in a qualitative and quantitative manner, before making any recommendation. The current pay zone underlying the Jacob field forms a monocline structure composed of unconsolidated young clastic sediments deposited in the Eocene epoch of the stratigraphic column of the Nueces River Basin, mainly due to a fluvial deltaic system developed in south Texas. The original oil in place for this pay zone was estimated to be 18.12 MMSTB and the cumulative production as of October 2003, 3.8 MMSTB. The analysis of the production data available had shown that the pay zone is being flooded by a strong water encroachment from the lower sides of the structure. This behavior was confirmed by the anisotropy analysis from core and log data, which shows that the reservoir tends to be more homogeneous in the direction of the water encroachment. It seems that there is not much room for further development in the current pay zone in the Jacob field (the remaining reserves were estimated to be 10 MSTB as of October 2003). However, the presence of a continuous shallow clean sandstone, not properly tested, of better reservoir properties than the actual pay zone was noticed. Moreover, this clean sandstone showed oil and gas presence in thirteen wells in the drilling cuttings. Therefore further development should concentrate more on investigating and developing the oil potential of the latter sandstone as well as accelerating the reserves production in the actual pay zone by means of waterflooding and/or infill drilling.