A locally conservative mixed finite element framework for coupled hydro-mechanical-chemical processes in heterogeneous porous media

This paper presents a mixed finite element framework for coupled hydro-mechanical–chemical processesin heterogeneous porous media. The framework combines two types of locally conservative discretizationschemes: (1) an enriched Galerkin method for reactive flow, and (2) a three-field mixed finite element methodfor coupled fluid flow and solid deformation. This combination ensures local mass conservation, which iscritical to flow and transport in heterogeneous porous media, with a relatively affordable computational cost.A particular class of the framework is constructed for calcite precipitation/dissolution reactions, incorporatingtheir nonlinear effects on the fluid viscosity and solid deformation. Linearization schemes and algorithms forsolving the nonlinear algebraic system are also presented. Through numerical examples of various complexity,we demonstrate that the proposed framework is a robust and efficient computational method for simulationof reactive flow and transport in deformable porous media, even when the material properties are stronglyheterogeneous and anisotropic.