The mechanisms of ground surface subsidence above compacting multiphase reservoirs and their analysis by the finite element method

An analysis of multiphase flow through a compacting porous medium is investigated in this paper. The nonlinear partial differential equations governing the flow regimes are derived and a method of calculating the effective stress gradients is given. This method involves a local averaging technique to model the interaction of two immiscible fluid phases on a small volume of the deforming porous medium. The combined stress and flow problem is then solved using the finite element method where the flow is confined to a submesh of the whole region. A simulation is made of a typical vertical cross-section of the Forties Field.