Entrainment and Deposition of Fine Particles in Porous Media

Abstract

Entrainment and redeposition of naturally occurring fine particles in porous media has been suggested as a mechanism leading to abnormal decline in productivity of producing wells. This paper describes the results of studies conducted to determine factors affecting this phenomenon. Experimental work done as part of this study provides the basis for a proposed phenomenological theory of entrainment and deposition. The central concept of this theory is representation of both particle and pore size distributions by partitioning the porous medium at any cross section into parallel plugging and nonplugging pathways. This simple model appears to be completely adequate for describing a broad class of filtration and entrainment phenomena. We have shown that fines entrainment and redeposition are mechanisms that can cause abnormal productivity decline and are phenomena restricted to the near-wellbore region.