Water-cut reduction during waterflood by induced fines migration: effects of varying formation damage coefficient

Abstract

Decline of permeability during corefloods with low salinity and high pH water, has been widely reported in the literature. It has been explained by the lifting, migration and subsequent plugging of pores by fine particles, which has been observed in numerous core flood tests with altered water composition. This effect can be considered to provide a relatively simple method for mobility control during waterflooding. In previous research, the Dietz model for waterflooding in a layer-cake reservoir was combined with a particle detachment model to investigate the effect of fines migration and induced permeability decline on reservoir sweep efficiency and amount of injected water; the model was derived under the assumption of constant formation damage coefficient. In this work, the model was extended to the case where the formation damage, caused by captured fines, depends on absolute permeability of the rock. The modeling showed that the incremental recovery and reduced water cut, caused by induced fines migration, is lower for the case of formation damage coefficient decreasing with permeability increase, than for the case of constant formation damage coefficient.