On the unsteady flow of a compressible liquid through a porous medium

Summary

The unsteady flow of a compressible liquid in a porous medium can be described in terms of a non-linear partial differential equation for the liquid pressure or a linear differential equation for the density if gravitational effects are negligible. In gravitational flow fields the formulation yields non-linear equations for both density and pressure. A transformation is given which shows that in the absence of gravitational effects, the solution of the non-linear boundary value problem in terms of the pressure involves no more labour than the solution of the linear problem in terms of the density, contrary to a misconception in the petroleum literature. Furthermore this transformation offers in addition the solution to a heretofore unsolved problem in gravity flow.