Pore-scale simulation of fine particles migration in porous media using coupled CFD-DEM

Abstract

Transport of fine particles in porous media has attracted a considerable interest over the past several decades given its importance to many industrial and natural processes. In order to control fine particles transport in porous media, the behavior itself needs to be predicted and analyzed. Which could be quite costly to do in a laboratory experiment, hence the modelling of such a behavior would be an optimum way to study. In this work, we present a coupled computational fluid dynamics-discrete element method (CFD-DEM) based modelling framework that is capable of simulating the migration of a large number of fine particles, on the colloids size through physically realistic porous media. The model was parallelized using Message Passing Interface (MPI) protocol to resolve particle-particle and particle-grain interactions for a large number of fine particles. The model's geometry was generated from computed tomography images of sand packs, the CFD solver were set to solve the fluid flow while the DEM were to solve the particles physical interactions. Immersed Boundary Method (IBM) were used to couple the two solvers in a resolved manner. The model's setup was first validated to capture single phase fluid flow behavior and then the coupling of the fluid flow and particle interaction was compared to experimental results. In order to validate the coupled CFD-DEM model, velocity profiles of fine particles, their diffusion in the pore space and the percentage of fine particles retained in the pore space obtained from micromodel experiment were compared to values obtained from simulations using the same pore space geometry and initial experimental conditions. The presented framework was shown to capture the bulk dynamics of fine particulate transport and deposition within geologically realistic and complex flow domains while minimizing execution time. The model was used to study the impact of flow velocity and size of fines on permeability reduction of porous media due to migration of fine particles. Simulations indicate that permeability reduction due to fine migration in porous media is directly proportional to flow velocity. The time required to develop bridging and subsequent clogging of the pore space that lead to permeability reduction decreases as the flow velocity increases. The size of the fine particles has a significant impact on permeability reduction where the reduction in permeability increases as the size of particles increases. A faster and larger reduction in permeability was observed when a suspension of polydisperse particles was injected as opposed to a monodisperse suspension. 2022 The Authors