Lattice Boltzmann based multicomponent reactive transport model coupled with geochemical solver for pore scale simulations

Abstract

A Lattice Boltzmann (LB) based reactive transport model intended to capture reactions and solid phase changes occurring at the pore scale is presented. The proposed approach uses LB method to compute multi component mass transport. The LB multicomponent transport model is then coupled with the well-established geochemical reaction code PHREEQC which solves for thermodynamic equilibrium in mixed aqueous-solid phase system with homogenous and heterogeneous reactions. This coupling enables us to update solid phases volumes based on dissolution or precipitation using static update rules which, on pore scale, affects the change of potentially pore network geometry. Unlike conventional approach, heterogeneous reactions are conceptualized as volumetric reactions by introducing additional source term in the fluid node next to solid node, and not as flux boundaries. To demonstrate the validity of this approach several examples are presented in this paper.