Influence of water salinity on oil production performance during waterflooding: A simulation analysis

The water injection process can improve the performance of the production operation by maintaining reservoir pressure. The decrease in rock permeability due to salt precipitation usually occurs by mixing formation and injection waters. One way to reduce the formation damage is the reduction of ion concentrations in the injection water. Low salinity water injection (LSWI) reduces the formation damage, and can turn the reservoir from oil-wet to water-wet. In this work, a reservoir model with four productionwells and one injection well was utilized to analyze the recovery factor, total production rate, and water cut. The production was evaluated in periods. For the first ۲۰ years, the production was carried out without water injection. Then, for ۲۰ years, the water was injected at concentrations of ۵۰۰۰۰, ۲۵۰۰۰, ۱۰۰۰۰, ۵۰۰۰, and ۴۰۰۰ ppm. The simulation results showed the recovery factor after ۲۰ years without water injection was about ۲۸%. After water injection, the recovery factor was increased by ۹.۸% (at ۵۰۰۰۰ ppm) and ۱۴.۸% (at ۴۰۰۰ ppm). Also, the production rate was increased by decreasing the water salinity. The water cut was reduced by decreasing salinity and, as a result, oil production increased. The optimum salinity was ۵۰۰۰ ppm.

Keywords:

Low salinity water injection , oil production , simulation , water cut