Pore-scale mass and reactant transport in multiphase porous media flows

Abstract

Reactive processes associated with multiphase flows play a significant role in mass transport in unsaturated porous media. For example, the effect of reactions on the solid matrix can affect the formation and stability of fingering instabilities associated with the invasion of a buoyant non-wetting fluid. In this study, we focus on the formation and stability of capillary channels of a buoyant non-wetting fluid (developed because of capillary instabilities) and their impact on the transport and distribution of a reactant in the porous medium. We use a combination of pore-scale numerical calculations based on a multiphase reactive lattice Boltzmann model (LBM) and scaling laws to quantify (i) the effect of dissolution on the preservation of capillary instabilities, (ii) the penetration depth of reaction beyond the dissolution/melting front, and (iii) the temporal and spatial distribution of dissolution/melting under different conditions (concentration of reactant in the non-wetting fluid, injection rate). Our results show that, even for tortuous non-wetting fluid channels, simple scaling laws assuming an axisymmetrical annular flow can explain (i) the exponential decay of reactant along capillary channels, (ii) the dependence of the penetration depth of reactant on a local Péclet number (using the non-wetting fluid velocity in the channel) and more qualitatively (iii) the importance of the melting/reaction efficiency on the stability of non-wetting fluid channels. Our numerical method allows us to study the feedbacks between the immiscible multiphase fluid flow and a dynamically evolving porous matrix (dissolution or melting) which is an essential component of reactive transport in porous media.

Multiphase lattice Boltzmann simulations for porous media applications

“…[37,43,97,98,[197][198][199][200][201][202][203][204][205][206][207], because of its simplicity and easy implementation. Pan et al [197] used the MCMP inter-particle potential model to simulate two-phase flow in a porous medium comprised of a synthetic packing with a relatively uniform distribution of spheres.…”

Generalized three-dimensional lattice Boltzmann color-gradient method for immiscible two-phase pore-scale imbibition and drainage in porous media

“…(10). In general, we let the blue fluid be the least dense, and we set the value of 0 < α b = W 0 < 1 so that the relation 0 < α b α r < 1 is guaranteed to hold.…”

“…On the one hand, numerical simulation emerges as a flexible tool for engineering applications, and allows us for example to determine permeability curves for a given media [9]. On the other hand, simulation is a highly valuable tool for fundamental research in the field of multiphase fluid flows [10,11].…”

Upscaling Strategies of Porosity-Permeability Correlations in Reacting Environments from Pore-Scale Simulations

“…The more detailed ones solve the relevant flow equations or some approximation depending on the flow regime and the flow physics that are involved, in realistic geometries. Such methods are the lattice Boltzmann method [9][10][11][12][13], the methods based on particle hydrodynamics [14,15], as well as the standard finite volume methods when applied in complex geometries with moving boundaries [16][17][18]. Lattice Boltzmann models can resolve transport processes in realistic complex geometries, involving complex interactions between species and phases, but are more computational intensive compared to pore network models.…”