Investigation on oil displacement system of anionic gemini surfactant

The salt resistance and oil displacement performance of a new kind of gemini surfactant GA12-4-12 was investigated. This surfactant exhibits good surface activity in the aqueous blending solution of sodium chloride 2.35×10⁵ mg/L and calcium chloride 1.5×10⁴ mg/L, and its critical micelle concentration is 538.6 mg/L. The oil-water interface tension between the GA12-4-12 solution and thin oil decreases with the increase of the concentration of inorganic salt first and then tends to stable. It decreases to 2.2×10^-3 mN/m at the NaCl concentration of 250 g/L. Under the high-salinity simulation formation water, the oil-water dynamic interfacial tensions of GA12-4-12 and its composite system SP can reach the ultra-low value (10^-3 mN/m). Oil displacing simulation experiments show that GA12-4-12 and its composite system SP can increase oil recovery displaced water by 6.25% and 10.67%, respectively.