Objective The branched alcohol ether sulfonate TEOS was synthesized by branched alcohol ether TEO, 1, 3-propane sulfonate as a raw material. The surface tension (γ_cmc) under the concentration of micellar concentration (cmc) and the critical micelle concentration of branched alcohol ether TEO, TEOS, and the amphoteric Gemini surfactant GCS12 in distilled water was determined. The solution properties of branched alcohol sulfonates and amphoteric Gemini surfactants were studied.

Methods The surface activity of the alcohol ether sulfonate TEOS and the GCS12 compounding system was evaluated, and the interaction between them was studied. The interfacial activity between the binary compound system and Changqing crude oil was also studied.

Results The experimental results show that the content of synthetic alcohol ether sulfonate is 96.5%, it has good salt tolerance. The cmc of TEO, TEOS, GCS12 in distilled water is 0.05 mmol/L, 0.40 mmol/L, 0.05 mmol/L, respectively, and γ_cmc is 26.02 mN/m, 34.58 mN/m, 25.27 mN/m, respectively. The theoretical study of solution thermodynamics showed that TEOS and GCS12 had medium interaction to significantly reduce the critical micelle concentration of mixed solution. The mixed solution prepared with simulated formation water at 60 ℃ reached the minimum interfacial tension when n(TEOS)∶n(GCS12)=3∶1. When the amount of salt is 200 g/L, the interfacial tension is 0.021 mN/m.

Conclusions The mixing systems of branched alcohol ether sulfonate and amphoteric Gemini surfactant have better temperature resistance and high interface activity, which can provide a technical support for the development of oil displacement surfactant.