Abstract
Summary Fluid-flow-driven particle migration through porous networks reflects the interplay between various particle-level forces, the relative size between migrating particles and pore constrictions, and the spatial variability of the velocity field. Experimental evidence shows that particle migration in radial fluid flow results in self-stabilizing annular clogging patterns when the particle size approaches the constriction size. Conversely, flow localization and flushing instability are observed when the particle size is significantly smaller than the pore-throat size. Introduction Fluid flow through a porous network is often accompanied by the migration of fine particles. This is a common phenomenon in geomaterials (Gruesbeck and Collins, 1982; Ryan and Elimelech 1996), filters (Kenney et al. 1985; Bigno et al. 1994; Bhatia et al. 1998; Reddi et al. 2000), and biological systems (Bonala and Reddi 1998). In certain conditions, massive particle clogging develops, reducing the medium's fluid-transport capacity and thus decreasing productivity (Muecke 1979; Priisholm et al. 1987; Khilar and Fogler 1998). In other cases, particles are flushed out of the medium, yielding an increased fluid conductivity (Kenney and Lau 1985; Skempton and Brogan 1994). In this study, particle migration and retention are analyzed at the microscale to identify governing particle-level phenomena, with emphasis on mechanical processes rather than electrical interactions, which have been analyzed by previous researchers (e.g., Jones 1964; Cerda 1987; Kia et al. 1987; Sharma and Yortsos 1987; Vaidya and Fogler 1990; Raveendran and Amirtharajah 1995). At the macroscale, clogging and flushing patterns are investigated in radial flow, where the fluid velocity and the forces experienced by migratory particles vary in space.