Density profile and flow of driven gas in an open porous medium with a computer simulation

Abstract

A computer simulation model is used to study the flow of gas from a source through open porous media on a simple cubic lattice with a pressure bias. This model is used to represent marine sediments through which fluid flows. Isotropic and layered porous media are considered and the gas fluid is modeled by an interacting lattice gas. In isotropic porous medium with porosity p s =0.35, the density profile is linear in the absence of bias ( B=0) and oscillations develop in the presence of bias. At low porosity ( p s =0.32), the density profile becomes nonlinear in the presence of bias. The response of the flow rate to bias is linear in media with high porosity – consistent with the Darcy law. In porous medium with low porosity, the response of flow rate is linear only in low bias ( B⩽0.3) which crosses over to a different linear response at moderate values of bias (0.30⩽ B⩽0.7) before it becomes negative at extreme bias ( B⩽0.8). The presence of fault planes (i.e., linear zones of higher porosity within a low-porosity system) broadens the linear-response regime.