Research and application of ultralow interfacial tension oil displacement agent.

An ultralow interfacial tension (IFT) oil displacement agent, which was a surfactant combinational system (HCS) with good salt and heat resistance, was synthesized using amphoteric betaine (AMS)/anionic sulfonate (AKS)/nonionic alkyl amide (NIS). The interface tensiometer was used to test the IFT. The results showed that the oil–water IFT could be as low as 10−4mN/m when the salinity is 10,000∼50,000 mg/L, the concentration is 1∼5 g/L, and the temperature is 40∼80°C. The surfactant system has good emulsification stability. The displacement simulation experiments demonstrated that the increment of the recovery ratio can be up to 14.1%. The surfactant system could meet the demands of site operation. [ABSTRACT FROM PUBLISHER]