Abstract: In order to achieve the effect of decompression and augmented injection, sulphonate surfactant was adopted to reduce IFT between oil and water by Taibei SII group, which required optimizing and adjusting formulation of surfactant. The variety and concentration of alcohols and salt assistants were screened to reduce IFT of oil-water interface, and test of evaluation on surfactant resistance was used to highlight its characteristics and the optimal application conditions. The results show that the effect of mixed reagent of 0.1%~0.8% ethanol, normal butyl alcohol and sulphonate outperforms that of methanol, normal propyl alcohol and glycerin. With increase of salt concentration, the surface tension first descends and then rises, showing a L-shaped curve. The surfactant has better activity on formation of 50 ℃ within 15 d. The influence of mineralization degree on IFT between oil and surfactant approximates to "Ω" shape. The slightly alkaline condition is favorable for the action of surfactant. Core displacement test shows that optimized surfactant can achieve 18.7% depressurization, and the effect is better.

Key words: Surfactant, Assistant, Alcohol, Salt, Optimization

摘要： 为实现降压增注效果,太北SII组采用磺酸盐表面活性剂降低油水界面张力(IFT),需要对表面活性剂配方进行优化调整。通过对醇类和盐类助剂种类和浓度的筛选降低油水界面张力(IFT),并对表面活性剂抗性及最佳应用条件进行考察。结果表明,质量分数为0.1%~0.8%乙醇和正丁醇与磺酸盐混合试剂对IFT的作用效果优于甲醇、正丙醇和丙三醇;随着盐类质量分数升高,IFT先降后升,曲线呈现斜L型;表面活性剂在50 ℃地层中15d 内活性较好;矿化度对油与表面活性剂之间的IFT 影响趋势近似“Ω”型,偏碱性条件对表面活性剂作用是有利的。岩心驱替试验表明,优化后的表面活性剂可实现降压18.7%,效果较好。

关键词: 面活性剂, 助剂, 醇类, 盐类, 优化