Colloid Retention in Porous Media in the Presence of Energy Barriers: Hemispheres-in-Cell Model with Heterogeneity

Experimental evidences indicate that surface heterogeneities (charge and/or roughness) play an important role in colloidal retention in porous media under conditions when colloid-surface repulsion exists, at least for colloids of relatively small sizes (e.g. about 2 microns or less). Hence, we have incorporated surface charge heterogeneity into our recently delevoped hemispheres-in-cell model, with an aim to have a better understanding of colloid retention mechanisms in the presence of repulsive energy barriers via numerically simulating the transport and deposition behavior of different size colloids under the coupled effect of heterogeneity, pore structure (e.g. grain to grain contacts), fluid hydrodynamics, etcetera. Here we describe the strategies employed to account for heterogenously charged collector surfaces in the hemispheres-in-cell model so as to correctly compute the colloid-surface internation forces, and then present preliminary results obtained from this model on colloidal retention under various coverage of heterogenous attractive domains over the collector surfaces.