An iterative compositional model for subsurface multiphase flow

Abstract

The governing equations describing multiphase flow with multicomponent solute transport may be cast in a number of forms. While mathematically equivalent, the numerical models based on each formulation differ in flexibility and efficiency. The set-iterative compositional formulation, a mathematical formulation that separates the solution of the phase-balance equations from the species balance is described herein. A mathematical model based on this formulation describes the flow of two mobile phases. Each phase may transport multiple chemical components. Mass exchange between phases is expressed by a linear kinetic equation. The numerical model based on the set-iterative compositional formulation is shown to model non-equilibrium phase partitioning, to provide a flexible framework that may be applied to organic mixtures with differing numbers of components and to yield a more efficient solution in comparison with models arising from standard compositional formulations.