Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 45-47).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 159-167).

Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 69-72.

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Natural gas is an important energy source that contributes up to 25% of the total US energy reserves (DOE 2011). An increase in natural gas demand spurs further development of unconventional resources, including methane hydrate (Rajnauth 2012). Natural gas from methane hydrate has the potential to play a major role in ensuring adequate future energy supplies in the US. The worldwide volume of gas in the hydrate state has been estimated to be approximately 1.5 x 10^16 m^3 (Makogon 1984). More than 230 gas-hydrate deposits have been discovered globally. Several production technologies have been tested; however, the development of the Messoyakha field in the west Siberian basin is the only successful commercial gas-hydrate field to date. Although the presence of gas hydrates in the Messoyakha field was not a certainty, this current study determined the undeniable presence of gas hydrates in the reservoir. This study uses four models of the Messoyakha field structure and reservoir conditions and examines them based on the available geologic and engineering data. CMG STARS and IMEX software packages were used to calculate gas production from a hydrate-bearing formation on a field scale. Results of this analysis confirm the presence of gas hydrates in the Messoyakha field and also determine the volume of hydrates in place. The cumulative production from the field on January 1, 2012 is 12.9 x 10^9 m^3, and it was determined in this study that 5.4 x 10^9 m^3 was obtained from hydrates. The important issue of pressure-support mechanisms in developing a gas hydrate reservoir was also addressed in this study. Pressure-support mechanisms were investigated using different evaluation methods such as the use of gas-injection well patterns and gas/water injection using isothermal and non-isothermal simulators. Several aquifer models were examined. Simulation results showed that pressure support due to aquifer activity was not possible. Furthermore, it was shown that the water obtained from hydrates was not produced and remained in the reservoir. Results obtained from the aquifer models were confirmed by the actual water production from the field. It was shown that water from hydrates is a very strong pressure-support mechanism. Water not only remained in the reservoir, but it formed a thick water-saturated layer between the free-gas and gas-hydrate zone. Finally, thermodynamic behavior of gas hydrate decomposition was studied. Possible areas of hydrate preservation were determined. It was shown that the central top portion of the field preserved most of hydrates due to temperature reduction of hydrate decomposition.

The sedimentary wedge of the northern Gulf of Mexico is extensively deformed and faulted by salt tectonics. Industry 2-D multichannel seismic data covering a large area (33,800 km2) of the lower Texas continental slope [96 degrees 40'- 93 degrees 40'W; 27 degrees 10N - 26 degrees N] were examined to evaluate the interplay of salt, faults and gas. Seismic interpretation revealed the study area has two different styles of faulting and two different types of salt bodies that vary east to west. The eastern region of the study area has a thin sedimentary section and a massive, nearly continuous salt sheet characterized by minibasins and local salt highs. Faulting in this area appears to be the result of salt tectonism. The western region of the study area has a thick sedimentary wedge, and a few isolated salt diapirs. Long, linear faults are parallel to slope and imply some degree of gravitation sliding. The difference in faulting styles and salt bodies can be attributed to different depositional environments, different styles and amounts of sediment loading and different amounts of salt initially deposited. While there is a widespread occurrence of gas throughout the study area, little evidence of continuous bottom simulating reflectors (BSRs), a widely accepted geophysical indicator of gas hydrate, has been found. The gas hydrate stability zone (GHSZ) was modeled to provide information on the thickness and variability of the stability zone, and provide a baseline in a search for BSRs. The dataset was analyzed for multiple seismic expressions of BSRs, however only a few small and isolated examples were found. Potential fluid escape structures were seen in the seismic data. Despite the great number of potential features found in the seismic data only seven active seeps were found in a seep study by I. R. MacDonald. Seeps were seen in far less abundance than the number of seeps found offshore Louisiana. This may imply a lack of source offshore Texas.

Natural gas hydrates are solid crystalline substances found in the subsurface. Since gas hydrates are stable at low temperatures and moderate pressures, gas hydrates are found either near the surface in arctic regions or in deep water marine environments where the ambient seafloor temperature is less than 10°C. This work addresses the important issue of geomechanical stability in hydrate bearing sediments during different perturbations. I analyzed extensive data collected from the literature on the types of sediments where hydrates have been found during various offshore expeditions. To better understand the hydrate bearing sediments in offshore environments, I divided these data into different sections. The data included water depths, pore water salinity, gas compositions, geothermal gradients, and sedimentary properties such as sediment type, sediment mineralogy, and sediment physical properties. I used the database to determine the types of sediments that should be evaluated in laboratory tests at the Lawrence Berkeley National Laboratory. The TOUGH+Hydrate reservoir simulator was used to simulate the gas production behavior from hydrate bearing sediments. To address some important gas production issues from gas hydrates, I first simulated the production performance from the Messsoyakha Gas Field in Siberia. The field has been described as a free gas reservoir overlain by a gas hydrate layer and underlain by an aquifer of unknown strength. From a parametric study conducted to delineate important parameters that affect gas production at the Messoyakha, I found effective gas permeability in the hydrate layer, the location of perforations and the gas hydrate saturation to be important parameters for gas production at the Messoyakha. Second, I simulated the gas production using a hydraulic fracture in hydrate bearing sediments. The simulation results showed that the hydraulic fracture gets plugged by the formation of secondary hydrates during gas production. I used the coupled fluid flow and geomechanical model "TOUGH+Hydrate- FLAC3D" to model geomechanical performance during gas production from hydrates in an offshore hydrate deposit. I modeled geomechanical failures associated with gas production using a horizontal well and a vertical well for two different types of sediments, sand and clay. The simulation results showed that the sediment and failures can be a serious issue during the gas production from weaker sediments such as clays.

Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains xiii, 111 p. : ill. Includes abstract. Includes bibliographical references.