适合特低渗透油藏的表面活性剂驱油体系研究及应用

Research and Application of Surfactant Flooding System Suitable for Ultra-Low Permeability Reservoir

为进一步提高特低渗透油藏水驱开发后的采收率,将界面活性较强的新型两性离子双子表面活性剂MGS-3和乳化能力较强的阴离子型表面活性剂AES相结合,研制了一种适合特低渗透油藏的复合表面活性剂驱油体系,具体配方为0.2%MGS-3+0.1%AES,并评价了其界面活性、乳化性能、吸附性能、润湿性能和驱油效果。结果表明:该复合表面活性剂驱油体系具有良好的界面活性,能使油水界面张力达到10^(-3)mN/m数量级;体系具有较强的乳化能力,乳状液静置120 min后的析水率约为50%;此外,该复合表面活性剂驱油体系还具有良好的抗吸附性能和润湿改变能力;特低渗岩心水驱后注入复合表面活性剂驱油体系能使采收率继续提高20%以上,驱油效果明显优于单一表面活性剂。现场应用结果表明,S区块实施复合表面活性剂驱油措施后生产井的日产油量显著提升,含水率有所下降,取得了明显施工效果,具有较好的推广应用前景。

In order to further improve the oil recovery of ultra-low permeability reservoir after waterflooding,a composite surfactant flooding system suitable for ultra-low permeability reservoir was developed by a new amphoteric Gemini surfactant MGS-3 with strong interfacial activity and an anionic surfactant AES with strong emulsifying ability(formula is 0.2%MGS-3+0.1%AES),and its interfacial activity,emulsifying property,adsorption property,wettability and oil displacement effect were evaluated.The results show that the composite surfactant flooding system has good interfacial activity,which can make the interfacial tension of oil and water reach the order of 10^(-3) mN/m;the system has strong emulsification ability,and the water evolution rate of the emulsion after 120 minis about 50%;the composite surfactant flooding system also has good adsorption resistance and wetting change ability;the composite surfactant flooding system can make the oil recovery of ultra-low permeability cores after water flooding of improved by more than 20%,whose oil displacement effect is obviously better than that of single surfactant.The field application results show that the composite surfactant flooding system can make the daily oil production of the production wells in block S significantly increased and the water cut decreased,and it has a good prospect of popularization and application.