Optimized Surfactant IFT and Polymer Viscosity for Surfactant-Polymer Flooding in Heterogeneous Formations

Abstract

Abstract Surfactant Polymer flooding (SP flooding) has drawn more attention than Alkaline Surfactant Polymer flooding (ASP flooding) in China due to the difficulty of demulsification and the scale formation problem from the alkali in ASP. Traditionally, the primary requirement for the surfactant in SP flooding is the lowest interfacial tension (IFT). However, core flooding tests performed in a series of heterogeneous models have demonstrated there exist optimized surfactant IFT and polymer viscosity for SP flooding, which can maximize the oil recovery of a heterogeneous formation. The optimized surfactant IFT has a low value but not the lowest possible value, and polymer viscosity is at an appropriately high value, but not the highest possible value. This paper summarizes and analyzes more than 40 core flooding test results and provides possible mechanisms for the results.