The Implementation and Numerical Analysis of Fully-Coupled Non-Isothermal Fluid Flow Through a Deformable Porous Medium

Abstract

This work seeks to simulate subsurface fluid flow and heat transport within a deformable porous medium. Previous work indicates that it is imperative to consider the in situ spatial fluctuations recorded in well-log and well-core data to achieve accurate numerical flow simulations for nondeforming porous solids. The consideration of in situ spatial property fluctuations naturally gives rise to preferential pathways of fluid flow and heat transport. Provision for solid deformations offers a logical step forward to allow for stress-controlled fluctuation evolution of in situ properties. A sophisticated numerical model will be able to capture the growth and collapse of in situ voids, fractures, and fracture connectivity due to variation in fluid pressure and flow, faulting, and temperature as, say, induced at Enhanced/Engineered Geothermal System (EGS) projects. The relevant linear momentum, mass, and enthalpy balance equations have been coupled in a combined finite element and finite difference analysis. The governing differential equations and discretized set of equations are realized in preliminary results for 2D vertical planes in which one or more horizontal wellbores act as flow sources/sinks. The model presented in this work is a critical first step toward full 3D EGS heat exchange reservoir development and fluid flow simulation.