Warm water flooding of confined gas hydrate reservoirs

Large quantities of natural gas hydrate are present in marine sediments along the coastlines of many countries as well as in arctic regions. This research is aimed at assessing techniques to produce natural gas from marine hydrate deposits. A multiphase, multicomponent, thermal, 3D simulator is used, which can simulate production of hydrates both in equilibrium and kinetic modes. Three components (hydrate, methane, and water) and four phases (hydrate, gas, aqueous-phase, and ice) are considered in the simulator. In this work, we simulate warm water flooding and depressurization for hydrate production from a confined reservoir with a hydrate layer underlain by a water layer. Water flooding has been studied as a function of injection temperature, injection pressure and production pressure. For high injection temperature and high production pressure, warm water injection is preferred over depressurization; an increase in injection pressure increases the heat influx to the reservoir making the gas production faster. If a low pressure can be maintained at the production well or the injection temperature is not high, then just depressurization is the best method of production. As reservoir porosity and permeability increase and the heat transfer coefficient to the over- and under-burden decreases, the warm water injection process becomes more favorable.