Numerical Study of Non-Isothermal Filtration Process Considering the CO$${}_{\mathbf{2}}$$–CH$${}_{\mathbf{4}}$$ Replacement in Methane Hydrate

Currently an interest in the prospects of gas production and primarily production of methane from natural gas hydrate deposits is growing worldwide. It is necessary to develop and calculate methods of such production to uninterruptedly switch from traditional extracted gas (reserves are estimated for approximately 50 years) to gas from gas hydrate deposits (reserves are estimated for at least 250 years) in the future, which will allow the extraction of natural gas for a sufficiently long time. A number of researchers consider the replacement of methane in its hydrate with carbon dioxide as a promising method for extracting methane from gas hydrate deposits. In this regard, the paper considers the process of injecting carbon dioxide into a formation initially saturated with methane and its hydrate in a one-dimensional axisymmetric approximation considering the process of CO $${}_{2}$$ –CH $${}_{4}$$ replacement in the gas hydrate. Equations for calculating the values of the main parameters of the non-isothermal filtration process in the formation are presented. Numerical solutions for the considered problem in the form of distributions in the reservoir of pressure values, temperature, mass concentrations of gas phase components and saturations of methane and carbon dioxide hydrates are constructed. Conclusions are made about the influence of various parameters on the process of non-isothermal filtration and the process of CH $${}_{4}$$ –CO $${}_{2}$$ replacement in gas hydrate in the reservoir.