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. This effect can be considered to provide a relatively simple method for mobility control during waterflooding.
In this work, basic equations for waterflooding with salinity variation causing detachment of fine particles, their migration and straining are derived. It is shown that in the large scale approximation the model is equivalent to the adsorption-free polymer flood model, which allows taking advantage of polymer flood simulator for modelling of the waterflood with fines. 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.