Fully Coupled Numerical Simulation Of Fractured Porous Media With Elasto-Brittle-Plastic Deformation

This paper worked out the fully coupled numerical simulation of naturally fractured reservoirs based on the dual porosity model.1. The relationships between the elasto-brittle-plastic strains of a fractured porous medium saturated with compressible fluids and its dual porosity, dual permeability have been given. This relationship is prior to the models, which relate the porosity, permeability with fluid pressures or effective stresses within the medium because the former can describe the comprehensive effect on porosity and permeability change and their unrecoverable behaviors.2. Based on the conventional multicomponent model, this paper presented a set of coupled governing equations for multicomponents, multiphase fluid flows within the fractured porous medium, which taking into account the interactive effect of soil deformation and fluid flows. After simplifying under conditions, the coupled flow governing equations for three-phase fluid & three components have been obtained.3. One kind of elasto-brittle-plastic constitutive model has been given and used to describe the fractured porous medium deformation. The corresponding incremental elasto-brittle-plastic finite element solution scheme has been proposed. Combining the generalized effective stress principle and the coupled multiphase fluid model, as well as new porosity model & permeability model proposed above, a new fully coupled mathematical model for multiphase fluid flow within fractured porous medium was developed. Considering the solid displacements and the fluid pressures as primary unknowns, the Galerkin-based finite element method was applied to discretize the governing equations both in space and time domain.4. The corresponding computer codes have been developed all alone.5. The computer program developed by author was be used to simulate a typical naturally fractured reservoir and to be verified. Based on the results of numerical simulation, some practical phenomena can be understood more clearly, and some constructive suggestions have been proposed.