低渗透油藏驱油用表面活性剂SAS体系及性能评价

Performance Evaluation of the Surfactant SAS system for Oil Displacement in Low-permeability Reservoirs

针对长庆油田王窑加密区长6油藏特征,开发出一种聚乙二醇辛基苯基醚、十二烷基苯磺酸钠与有机溶剂乙醇复配而成的表面活性剂SAS体系,并从油水界面张力、热稳定性、静态吸附性能（吸附对界面张力的影响和吸附量的测定）、天然岩心进行驱油效率等方面对其进行了性能评价。结果表明,在55℃及50000mg/L矿化度的条件下,表面活性剂质量分数在0.05%~0.4%的范围内,油水界面张力可在30min内快速降至10-3 mN/m;SAS体系具有较好的热稳定性,在地层中能长期保持低界面张力,能够起到较好的驱油作用;SAS体系在吸附11次后界面张力仍然超低（小于10-2 mN/m）,并且不同质量分数下的吸附损耗量均低于5mg/g,抗吸附性能优异;SAS体系在水驱基础上分别提高采收率4.5%、5.54%,有效提高驱油效果,满足低渗透油田提高采收率技术需要。

the surfactant SAS system,which is comprised of p-octyl polyethylene glycol phenyl ether,sodium dodecyl benzene sulfonate and organic solvent,is developed in consideration of the feature of Chang-6Reservoir in Wangyao Block of Changqing Oilfield.The performance evaluation is taken from the oil-water interfacial tension,thermal stability,static adsorption properties,and the oil displacement efficiency of natural core.The results show that when the mass fraction of surfactant is from 0.05%to 0.4%,the oil-water interfacial tension decreases to 10-3 mN/m in 30 minutes at 50℃ and the salinity of 50000mg/L.The SAS system has better thermal stability and it can keep low interfacial tension,and is good at the oil displacement.After absorbing for 11 times,the SAS system has ultra-low interfacial tension.The absorption loss rate is under 5mg/g at different mass fractions.the excellent anti-adsorbability is showed by the system.The recovery factor increase 4.5% and 5.54% based on the water flooding by the SAS system.The system can improve the oil displacement efficiency,satisfy the requirements of the enhanced oil recovery technology for low-permeability oilfield.