Pore-Scale Study of Non-Clogging Accumulation Effects on Microgel Particle Transport and Multiphase Displacements in Porous Media

Abstract

Particle transport in subsurface porous media under multiphase flow conditions is widely concerned in many practical applications. Previous studies have focused on retention behaviors and interfacial effects, ignoring the unique role of pronounced rheological effect under dilute conditions. Here, we investigate how accumulation effect reshapes microgel particle transport and immiscible displacement process driven by concentration-sensitive viscosity. As a foundation, a mixture-rheology two-fluid model is developed and combined with color-gradient lattice Boltzmann method for modeling complex particulate multiphase flow. The consistency between simulation results and microfluidic experiments confirms the validity of our model in capturing accumulation phenomena. Results in heterogeneous dual-permeability structures reveal the two-way coupling between particle accumulation and interfacial evolution. Particle accumulation can be enhanced at higher injection concentrations and larger particle sizes, leading to the formation of filter-cake-like structures despite the absence of clogging effects. Capillary resistance further weakens the driving force for particle migration, intensifying local accumulation compared to suspension flow. The non-uniform concentration distribution contributes to flow rate reallocation via diversion effects, producing variable displacement patterns under varying conditions. Results in disordered media exhibit a similar trend as in the dual-permeability model but with more significant accumulation. The dramatic reduction in nonaqueous phase saturation by sweeping efficiency improvement indicates the promising application potential of such accumulation. Our findings deepen the understandings of particle transport in porous media with implications for manipulation of immiscible displacement.