Numerical Study of the Process of Gas Extraction from a Gas Hydrate Reservoir with Inhomogeneous Permeability

Mathematical modeling of the process of gas extraction from a hydrate-containing reservoir, which is a cylindrical region of a porous medium, is performed. The reservoir consists of two interlayers with different permeabilities. The mathematical model includes equations of piezo- and thermal diffusivity, equations of state for gas and water, dependencies for determining relative phase permeabilities for gas and water; the phase transition was considered as thermodynamically equilibrium. The numerical implementation of the mathematical model was carried out using an implicit difference scheme, the sweep method, the method of simple iterations, and the method developed by the authors for calculating hydrate saturation. Numerical solutions of the problem are obtained that describe the distributions of parameters (temperature, pressure, phase saturations) in the reservoir.