Decoupling preconditioners in the implicit parallel accurate reservoir simulator (IPARS)

This paper presents an overview of two-stage decoupling preconditioning tec hniques employed in the implicit parallel accurate reservoir simulator (PAR S) computational framework for modelling multicomponent multi-phase flow in porous media. The underlying discretization method is implicit Euler in ti me and mixed finite elements or cell-centred finite differences in space. P ARS permits rigorous, physically representative coupling of different physi cal and numerical flow models in different parts of the domain and accounts for structural discontinuities; the framework currently includes eight phy sical models. For simplicity of exposition, we have restricted our discussi on to a two-phase oil-water model and a three-phase black oil model. Our de coupling approach involves extracting a pressure equation from the fully co upled linearized system thus allowing for a more accurate preconditioning o f a discrete elliptic problem of lower dimension. Copyright (C) 2001 John W iley & Sons, Ltd.