Preparation and Characterization of an Anionic Gemini Surfactant for Enhanced Oil Recovery in a Hypersaline Reservoir

Abstract A new type of anionic Gemini surfactant (AGS) was designed and prepared by a simple, low–cost, and green method, and its properties were characterized. The results showed that the values of parameters such as critical micelle concentration (CMC) value, Γmax, Amin, and pC20 of AGS were 0.10 mmol L −1 , 1.62 mmol m −2 , 1.02 nm 2 , and 4.60, respectively, indicating that AGS is highly surface active. AGS has a very good synergistic effect with lauryl diethanol amide (6501), and the mixture surfactant 6501DA (composed of AGS and 6501 with a mass ratio of 1:2.5) has good wetting and emulsifying ability of the crude oil and good resistance to calcium and magnesium ions. In the temperature range from 50 to 70 °C, salinity of 20,000–50,000 mg L −1 of the simulated formation water, and dosage of 6501DA from 500 to 3000 mg L −1 , all the interfacial tension (IFT) values between the 6501DA solution and Bamianhe crude oil were lower than 10 −2 mN m −1 , and all the adsorption amounts of oil sand to 6501DA in solution were less than 2 mg g −1 , indicating that AGS has potential for application in EOR in a hypersaline reservoir.