A Laboratory Study of Surfactant Flooding System for Tertiary Recovery in High-temperature and High-salinity Reservoirs

In order to further enhance oil recovery in high-temperature and high-salinity reservoirs, the surfactant flooding system for tertiary recovery in high-temperature and high-salinity reservoirs was investigated based on Tahe oilfield where the formation temperature is 90–110°C, the salinity of formation water is 11.5 × 104 mg/L, and the content of calcium-magnesium-ion is 5000–8000 mg/L. First of all, the surfactant formula suitable for Tahe oilfield reservoir was explored and optimized by means of compatibility experiments, interfacial tension measurements and thermal stability investigation. Then, the performance of the surfactant formulation was evaluated by results of changing wettability, emulsifying property, and adsorption capability, as well as flooding experiment and self-assembly behavior. Finally, a complete set of evaluation and optimization techniques applied to the surfactant flooding system for tertiary recovery in high-temperature and high-salinity reservoirs were developed, which provides theoretical basis and technical support for tertiary recovery in other high-temperature and high-salinity reservoirs at home and abroad.