Study of Surfactant–Polymer Flooding in High-Temperature and High-Salinity Carbonate Rocks

Abstract

Secondary waterflood processes have low oil recovery in carbonate reservoirs as a result of their oil-wetness and heterogeneity. Surfactants in combination with polymer solutions can improve the oil recovery significantly from these reservoirs through ultralow interfacial tension (IFT), mobility control, and wettability alteration. However, application of surfactant–polymer (SP) flooding in high-salinity and high-temperature carbonate reservoirs is constrained by the thermal stability of polymers at elevated temperatures, compatibility of surfactants with a high concentration of divalent cations present in formation brines, and geochemical interactions with carbonate minerals. This research is focused on understanding surfactant and polymer interactions with formation brines containing high concentrations of divalent cations and thermal stability and transport of polymers in carbonate rocks at a high temperature (80 °C). Surfactant phase behavior experiments (with and without polymer) were performed to id...