低渗透油藏驱油用耐温抗盐型表面活性剂研究

针对大庆油田M区块储层低孔、低渗、高温以及高矿化度的特点，采用常规表面活性剂往往不能取得较好的驱油效果。因此，以顺丁烯二酸酐、乙二胺和长链溴代烷为单体合成了一种新型双子表面活性剂SZ?11，并复配非离子型表面活性剂AEO?3，形成了一种适合低渗透油藏驱油用的耐温抗盐型表面活性剂驱油体系，并对其综合性能进行了评价。结果表明,该驱油体系具有良好的耐温性能和抗盐性能，在140 ℃下老化后，界面张力仍能达到0.008^{mN/m，体系在较高质量浓度的NaCl（150 000 mg/L）、CaCl₂（9 000 mg/L）和MgCl₂（2 500 mg/L）盐水中仍具有较低的界面张力；该驱油体系具有良好的乳化性能和润湿性能，可以通过乳化原油和改变岩石表面润湿性来提高驱油效率；储层天然岩心在水驱后注入0.4 PV表面活性剂驱油体系，能使岩心的采收率提高19.5%，具有良好的驱油效果。现场应用结果表明，实施表面活性剂驱油措施后，M区块内5口生产井日产油量明显提高，含水率下降，取得了良好的增油效果。}

Study on Temperature and Salt Resistant Surfactant for Oil Displacement in Low Permeability Reservoir

In view of the characteristics of low porosity, low permeability,high temperature and high salinity of reservoirs in block M of Daqing Oilfield,conventional surfactants cannot achieve good oil displacement effect.Therefore,a new type of surfactant SZ?11 was synthesized using maleic anhydride,ethylenediamine and long?chain alkyl bromides as monomers,and then mixed with non?ionic surfactant AEO?3.A new oil displacement system with higher temperature and salt resistant suitable for low permeability reservoir is formed,and its performance is evaluated.The results show that the prepared oil displacement system has good temperature and salt resistance.After aging at 140 ℃,the interfacial tension can still reach 0.008 mN/m.The system still has low interfacial tension in high concentration of sodium chloride (150 000 mg/L),calcium chloride (9 000 mg/L) and magnesium chloride (2 500 mg/L); the oil displacement system also has good emulsifying performance and wettability. The oil displacement efficiency can be improved by emulsifying crude oil and changing the wettability of rock surface. The oil recovery of reservoir core can be increased by 19.5% by injecting 0.4 PV prepared surfactant after water flooding step.The field application results show that after surfactant injection,the daily oil production of 5 production wells in block m is significantly increased,the water content is decreased, and better oil production increase effect is achieved.