Particle Migration and Clogging in Porous Media: A Convergent Flow Microfluidics Study

The migration and retention of fine particles in porous media are important phenomena in natural processes and engineering applications. Migrating particles experience physicochemical interactions with carrier fluids, pore walls, and other migrating particles. The governing dimensionless ratios capture particle-level forces, flow conditions, and geometric characteristics. This study explores micron-size particle migration and retention in microfluidic chips during convergent radial flow, which is the prevalent flow condition in water extraction and oil production. Pore-scale observations reveal the role of electrostatic interactions on clogging mechanisms: Glass particles experience retardation-accumulation bridging, while quasi-buoyant latex particles involve capture and clogging. Consequently, flow rates exert opposite effects on the clogging behavior of inertial glass particles versus electrostatically affected latex particles. Migrating particles experience a varying fluid velocity field in convergent radial flow, and clogging reflects the evolving local conditions (N-ad, Ar, Stk, and Re). In particular, clogged pores alter local flow and promote further clogging nearby. Pore network model simulations suggest that such dependent clogging lowers the permeability of the porous medium more effectively than independent clogging at random locations.