Gas hydrate is an ideal alternative energy source with high energy density and low combustion pollution. Based on the different distribution of methane hydrate, free gas and free water, gas hydrate deposits can be classified into four classes (Class 1, 2, 3 and 4). TOUGH+HYDRATE was used to simulate the dissociation process of depressurization in gas and water excess Class 2 and 3 methane hydrate deposits. The initial state and production pressure selection were the same as the experimental results. The simulation results were compared with the experimental results. In water excess condition, gas production volume in simulation is 1/3 higher than that in experiment, except hydrate production under 2.0 and 2.3 MPa in Class 3 deposit. It was found that the minimum temperature in simulation is larger than that in experiment during depressurization in Class 2 and 3 methane hydrate deposits when gas is excess.
Keywords methane hydrate, depressurization, water excess, gas excess