Effects of induced fines migration on water cut during waterflooding

Permeability decline during corefloods with varying water composition, especially with low salinity water, has been widely reported in the literature. It has often 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 (salinity, pH) and temperature. 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 with a constant injection and production rate was combined with a particle detachment model to investigate the effect of fines migration and induced permeability decline on reservoir sweep efficiency. In this work, the analytical model was extended to waterflooding with a given pressure drop between injection and production wells. The modelling showed that permeability decline in the water swept zone, caused by the alteration of the injected water composition and induced fines migration, may be able to improve waterflood performance by delaying water breakthrough and reducing the water cut.

► We propose using low salinity waterflood in fields where it induces fines migration.
► The modified Dietz’ waterflooding model accounts for fines migration.
► The fines migration results in permeability decrease & slowing water down.
► It redirects the injected water into poorly swept areas and increases sweep.
► It significantly reduces the injected & produced water volumes.