Finite element modelling of multiphase immiscible flow in deforming porousmedia for subsurface systems

A fully coupled numerical model has been developed which describes multipha se fluid flow through soil: namely gas, water and a nonaqueous phase liquid (NAPL) in a deforming porous media for subsurface systems. A multiphase fl ow model, based on the two-phase flow model of Brooks and Corey, is present ed to express the dependence of saturation and relative permeability on the capillary pressure. Nonlinear saturation and relative permeability on the capillary pressure. Nonlinear saturation and relative permeability function s are incorporated into a Galerkin finite element model which is subsequent ly used to simulate multiphase immiscible fluid flow under saturated and un saturated conditions in porous media. The governing partial differential eq uations, in terms of soil displacements and fluid pressures, which are coup led and non-linear, are solved by the finite element method. Numerical impl ementation of the formulation are discussed and example problems are perfor med to demonstrate the model and solution procedure. (C) 1999 Elsevier Scie nce Ltd. All rights reserved.