A Numerical Simulator for Modeling the Coupling Processes of Subsurface Fluid Flow and Reactive Transport Processes in Fractured Carbonate Rocks

Abstract

Water–rock interactions can alter rock properties through chemical reactions during subsurface transport processes like geological CO2 sequestration (GCS), matrix acidizing, and waterflooding in carbonate formations. Dynamic changes in rock properties cause a failure of waterflooding and GCS and could also dramatically affect the efficiency of the acidizing. Efficient numerical simulations are thus essential to the optimized design of those subsurface processes. In this paper, we develop a three-dimensional (3D) numerical model for simulating the coupled processes of fluid flow and chemical reactions in fractured carbonate formations. In the proposed model, we employ the Stokes–Brinkman equation for momentum balance, which is a single-domain formulation for modeling fluid flow in fractured porous media. We then couple the Stokes–Brinkman equation with reactive-transport equations. The model can be formulated to describe linear as well as radial flow. We employ a decoupling procedure that sequentially solves the Stokes–Brinkman equation and the reactive transport equations. Numerical experiments show that the proposed method can model the coupled processes of fluid flow, solute transport, chemical reactions, and alterations of rock properties in both linear and radial flow scenarios. The rock heterogeneity and the mineral volume fractions are two important factors that significantly affect the structure of conductive channels.

The influence of sedimentary heterogeneity on the diffusion of radionuclides in the sandy facies of Opalinus Clay at the field scale

“…The three-dimensional (3D) diffusion equation (Eq. 1) is solved numerically using a previously developed numerical simulator (Yuan et al, 2019;Yuan and Qin, 2020). By setting constant concentrations on both inlet and outlet and no flux at the other boundaries, the effective diffusion coefficient is calculated by the total mass flux J per unit cross-sectional area under steady-state conditions (Yuan and Fischer, 2021):…”

“…They pointed out that the anisotropic diffusion occurs mainly along bedding planes and the tracer concentrations is the result of a natural heterogeneity of the host rock. Among all different scales, the diffusivity is the key parameter for diffusive transport simulation (Yuan et al, 2019;Lu et al, 2022). Small-scale structural heterogeneities cause the variabilities in sedimentary and diagenetic facies in SF-OPA at larger scales.…”

Breakthrough Investigation of Advective and Diffusive Transport in a Porous Matrix with a Crack

“…Lonergan et al [20] included mineralization in their study. More complex situations covering reactive transport also attracted interest recently [21]. While transport studies in general deal with advection, diffusion, dispersion, sorption, and reaction we restrict our systematic approach to the physical processes, i.e., to advection and dispersion on a larger scale, what can be termed velocity dispersion [14].…”

A Novel Approach to Improve Acid Diversion in Carbonate Rocks Using Thermochemical Fluids: Experimental and Numerical Study

“…Matrix acidizing in carbonates aims to both remove damage near the wellbore area and further improve its permeability by creating conductive flow pathways (wormholes) around the wellbore [ 1 , 2 , 3 ]. Acid treating fluids designs have diverse compositions and formulations directed towards the targeted formation nature [ 4 , 5 ].…”