Modeling the Thickness of the Gas Hydrate Stability Zone and a Preliminary Estimation of Gas Hydrate Resource in the Oman Sea

According to a recent seismic survey in the Oman Sea, hydrate bearing layers were detected through observation of significant bottom simulating reflector, flat spot, and bright spot attributes in the area of 27,000 km2. This paper estimates the minimum water depth required for gas hydrate formation in the Oman Sea. Also, the thickness of the gas hydrate stability zone (GHSZ) is modeled on the basis of the Oman Sea basin properties. This leads to the first estimation of the volume of hydrate-bound gas sequestered in the Oman Sea. Using Milkov and Sassen’s model, the thickness of the GHSZ is calculated. Considering three different gas compositions, the minimum water depth stability calculations suggest that gas hydrate may crystallize as shallow as ~430 m to a water depth of ~872 m and the average thickness of the GHSZ was estimated to be ~217– 446 m in the Oman Sea. The estimated volume of hydrate-bound gas is 11–21×1012 m3 at standard temperature and pressure (STP) depending on the source gas composition, which is comparable to initial gas in place of South Pars gas field. Therefore, gas hydrate accumulation in the Oman Sea and free gas beneath could be a future energy source from which natural gas could be recovered profitably in the near future.