Chapter 11 - Alkaline-Polymer Flooding

Abstract

This chapter focuses on the interaction and synergy between alkali and polymer, and presents a field application of alkaline-polymer flooding. The interaction between alkali and polymer include alkaline effect on polymer viscosity, polymer effect on alkaline/oil interfacial tension (IFT), and alkaline consumption in alkaline-polymer systems. In alkaline-polymer flooding, alkaline reaction with crude oil results in soap generation, wettability alteration, and emulsification; and polymer provides the required mobility control. Alkaline-polymer flooding can displace more residual oil than individual alkaline flooding or polymer flooding. The combination of alkaline and polymer flooding can have three variations: alkaline injection followed by polymer injection (A/P), polymer injection followed by alkaline injection (P/A), and alkaline and polymer co-injection (A+P). The recovery factor from the third injection mode is not only higher than the alkaline injection alone or polymer injection alone, but also higher than that from the first or second mode. This synergy between alkaline and polymer flooding may be attributed to reduction in polymer adsorption and alkaline consumption, decreased biodegradation, increased viscosity of alkaline-polymer solution due to polymer to improve sweep efficiency, and reduction of polymer viscosity by alkaline in near wellbore region so that the injectivity is improved.