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.