Liquid Fragmentation Induced by Particle Aggregation During Two-Phase Flow in 3D Porous Media

Natural or engineered microparticles are often encountered in subsurface multiphase flow systems. This introduces a complex flow scenario with a variety of applications. However, the influence of particles on multiphase flow dynamics and the underlying mechanism remain elusive. Here, we investigate particle transport behavior and fluid phase distribution within 3D porous media through direct visualization utilizing laser scanning confocal microscopy. The mechanisms and factors governing particle aggregation during two-phase flow are elucidated. We identify a previously overlooked pore-scale phenomenon: fragmentation of wetting liquid induced by spontaneous particle aggregation in localized regions. This process dramatically increases the number of wetting clusters while reducing the fluid connectivity, resulting in a change in the relative permeability of fluids. These findings reveal the dynamic coupling mechanism between pore-scale particle aggregation and fluid flow and transport properties at larger scales, providing critical insights for predicting and controlling particle mediated geophysical flow processes.