天然来源的表面活性剂在超低渗油藏开发中的应用

Application of Natural Source Surfactants in Development of Ultra Low Permeability Reservoirs

因为国内大部分油田目前已经进入开发后期,在孔渗较好的圈闭已经钻探殆尽的大背景下,超低渗油藏开发便成了主要研究方向。在开发实践中,采用皂苷为原料制备了一种新型表面活性剂,这种活性剂为天然来源,并通过界面张力、接触角和石油采收率评估等实验说明其在以碳酸盐岩为代表的超低渗储层中具有良好的应用价值。评估了表面活性剂产生泡沫并在微观和宏观尺度上建立稳定乳液的能力。研究结果表明,当表面活性剂质量浓度达到1800 mg·L^(-1)时,界面张力将大幅度降低,最低达到0.39 mN·m^(-1)。此外,通过优化盐度,界面张力将降低到最低0.36 mN·m^(-1),这表明了盐度控制对于降低界面张力的作用。实验结果表明,该天然来源的新型表面活性剂在其临界胶束浓度下表现出优异的乳液稳定性,持续了6个月性质未发生显著变化;这种新型的表面活性剂产生的泡沫同样表现出了显著的稳定性,半衰期长达30 min。因此,在最佳条件下进行的驱油实验中,该新型表面活性剂溶液处于其临界胶束浓度并且盐度和碱度水平得到优化,原油采收率显著提高了25%,相比于传统的表面活性剂具有更为良好的化学性质,为未来的超低渗透油藏开发带来显著增益。

Due to the fact that most of the domestic oil fields have entered the late stage of development,the development of ultra-low permeability oil reservoirs has become the main research direction under the background that traps with good porosity and permeability have been drilled out.In development practice,a new type of surfactant was prepared using saponins as raw materials.This surfactant is a natural source and has good application value in ultra-low permeability reservoirs represented by carbonate rocks through experiments such as interfacial tension,contact angle,and oil recovery evaluation.The ability of surfactant to generate foam and establish stable emulsion on micro and macro scales was evaluated.The research results indicated that when the mass concentration of surfactants reached 1800 mg·L^(-1),the interfacial tension significantly decreased,reaching the minimum of 0.39 mN·m^(-1).In addition,by optimizing salinity,the interfacial tension was reduced to the minimum of 0.36 mN·m^(-1),indicating the role of salinity control in reducing interfacial tension.The experimental results showed that the new surfactant from natural sources showed excellent lotion stability at its critical micelle concentration,and its properties did not change significantly after 6 months.The foam produced by this new surfactant also showed remarkable stability,with a half-life of up to 30 min.Therefore,it can be concluded that in the oil displacement experiment conducted under optimal conditions,when the new surfactant solution is at its critical micelle concentration,and the salinity and alkalinity levels are optimized,the oil recovery rate of crude oil can be significantly improved by 25%,which has better chemical properties than traditional surfactants and will bring significant gains for the development of ultra-low permeability reservoirs in the future.