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

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. T his model is used to represent marine sediments through which fluid flows. Isotropic and layered porous media are considered and the gas fluid is mode led 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 re sponse of the flow rate to bias is linear in media with high porosity - con sistent with the Darcy law. In porous medium with low porosity, the respons e of flow rate is linear only in low bias (B less than or equal to 0.3) whi ch crosses over to a different linear response at moderate values of bias ( 0.30 B less than or equal to 0.7) before it becomes negative at extreme bia s (B less than or equal to 0.8). The presence of fault planes (i.e., linear zones of higher porosity within a low-porosity system) broadens the linear -response regime. (C) 2001 Published by Elsevier Science B.V. All rights re served.