Control Mechanisms for Gas Hydrate Production by Depressurization in Different Scale Hydrate Reservoirs

The methane hydrate was formed in a pressure vessel 38 mm in id and 500 mm in length. Experimental works on gas production from the hydrate-bearing core by depressurization to 0.1, 0.93, and 1.93 MPa have been carried out. The hydrate reservoir simulator TOUGH-Fx/Hydrate was used to simulate the experimental gas production behavior, and the intrinsic hydration dissociation constant (K0) fitted for the experimental data was on the order of 104 mol m-2 Pa-1 s-1, which was one order lower than that of the bulk hydrate dissociation. The sensitivity analyses based on the simulator have been carried out, and the results suggested that the hydrate dissociation kinetics had a great effect on the gas production behavior for the laboratory-scale hydrate-bearing core. However for a field-scale hydrate reservoir, the flow ability dominated the gas production behavior and the effect of hydrate dissociation kinetics on the gas production behavior could be neglected.