A Stable Method for Multi-component Gas Darcy Flow in Porous Media

A numerical model for multi-component gas Darcy flow in porous media is proposed in this paper. The model is capable of simulating underground gas storage operations and cushion gas flow while accounting for gas compressibility and coupling gas density and pressure. Gas properties are calculated using the Benedict–Webb–Rubin–Starling (BWRS) equation and the non-polar gas viscosity equation. The finite volume method is employed for discretization. Moreover, the computational stability of the proposed method is analyzed and verified. Compared to classical methods, the proposed method exhibits faster convergence with larger time steps. This is a significant advantage as it allows for more efficient simulations and faster results. To demonstrate the applicability of our model, we simulate two cases of UGS: a single well injection and a multiple wells injection. We find that the multiple wells injection method can effectively reduce the diffusion of cushion gas and increase the gas storage capacity.