On the selection of primary variables in numerical formulation for modeling multiphase flow in porous media

摘要

Selecting the proper primary variables is a critical step in efficiently modeling the highly nonlinear problem of multiphase subsurface flow in a heterogeneous porous-fractured media. Current simulation and ground modeling techniques consist of (1) spatial discretization of mass And/or heat conservation equations using finite difference or finite element methods; (2) fully Implicit time discretization; (3) solving the nonlinear, discrete algebraic equations using a Newton Iterative scheme.