多轮次吞吐热采用表面活性剂配方的实验室评价

Laboratory evaluation of surfactant formula in multiple rounds of steam huff and puff

针对胜利油田多轮次吞吐稠油油藏蒸汽驱油效率低、油品与蒸汽质量比降低等难题,通过筛选优化了表面活性剂中十八烷基苯磺酸钠(SOBS)和木质素磺酸钠(SLS)的配比,考察了优化配比后表面活性剂的乳化降黏、界面活性、润湿性、剥离原油、驱油等性能,利用石英晶体微量天平分析了岩芯表面原油的吸附量。实验结果表明,质量比7∶3的SOBS+SLS添加量为0.2%(w)时,胜利油田稠油的油水界面张力降低到0.12 mN/m,界面张力平衡时间20 min,乳化稠油黏度降低到35 mPa·s;岩心亲水性明显改善,由中性润湿变为亲水性润湿;油水界面张力降低使原油脱附速率增快,有助于油相剥离,提高驱油效率;在优化条件下,单管物模驱油效率提高13.22百分点。

In view of low steam displacement efficiency and decreased oil-steam ratio in heavy oil reservoirs with multiple rounds of huff and puff in Shengli Oilfield,the ratio of sodium octadecylbenzenesulfonate(SOBS)and sodium lignosulfonate(SLS)in the surfactant was screened and optimized.The performance of emulsification,viscosity reduction,interfacial activity,wettability,crude oil stripping,and oil displacement efficiency of the optimized surfactant was investigated.The adsorption capacity of crude oil on the surface of rock cores was analyzed using quartz microbalance.The experimental results show that for heavy oil in Shengli Oilfield,the optimized SOBS+SLS(mass ratio 7∶3)dosage of 0.2%(w)can reduce oil-water interfacial tension to 0.12 mN/m and viscosity to 35 mPa·s,with an interfacial tension equilibrium time for 20 min.The hydrophilicity of the rock core has also significantly improved,changing from neutral wetting to strong hydrophilic wetting.The decrease in oil-water interfacial tension increases the desorption rate of crude oil,which helps to remove oil from the reservoir and improve oil displacement efficiency.Under optimized conditions,the single-tube-physical-module oil displacement efficiency increases by 13.22 percent point.