Effects of injected-water salinity on waterflood sweep efficiency through induced fines migration

Abstract

Permeability decline during corefloods with varying water composition, especially with low-salinity water, has been observed in numerous laboratory studies. It has often been explained by the lifting, migration, and subsequent plugging of pores by fine particles, which have been observed in numerous coreflood tests with altered water composition. In this paper, we investigated the concept that this permeability decline may be used for mobility control during waterflooding. The Dietz model for waterflooding in a layer-cake reservoir with a given injection and production rate was combined with a particle-detachment model to provide a simple analytical model for the process. The application of the model to an example data set showed that the induced fines migration may improve sweep efficiency.