Simulation of Coupled Thermal/Hydrological/Mechanical Phenomena in Porous Media

Summary For processes such as production from low-permeability reservoirs and storage in subsurface formations, reservoir flow and the reservoir stress field are coupled and affect one another. This paper presents a thermal/hydrological/mechanical (THM) reservoir simulator that is applicable to modeling such processes. The fluid- and heat-flow portion of our simulator is for general multiphase, multicomponent, multiporosity systems. The geomechanical portion consists of an equation for mean stress, derived from linear elastic theory for a thermo-poroelastic system, and equations for stress-tensor components that depend on mean stress and other variables. The integral finite-difference method is used to solve these equations. The mean-stress and reservoir-flow variables are solved implicitly, and the remaining stress-tensor components are solved explicitly. Our simulator is verified by use of analytical solutions for stress- and strain-tensor components and is compared with published results.