适合超低渗油藏的高效渗吸剂体系及性能研究

Study on high efficiency imbibition system andperformance for ultra-low permeability reservoir

渗吸置换是超低渗油藏的有效驱油方式,高效渗吸剂的研发可大幅提高原油采收率。通过将重烷基苯磺酸盐类表面活性剂HAS-6及脂肪醇聚氧乙烯醚类表面活性剂G12-7N按照9∶1的配比复配,得到复配体系HAS-G,并对其界面性能、乳化性能、静态吸附性能、渗吸性能进行了评价。结果表明,在0.3%最佳浓度下,HAS-G体系与长庆油田Y区块脱水原油间界面张力可达6.9×10^(-3) mN/m;HAS-G体系可将油湿性云母片改性至水湿状态,接触角由115°降低至66.9°;HAS-G乳状液静置1 h后的乳化综合指数为0.11;HAS-G体系静态吸附量为9.3675 mg/g,较HAS-6体系静态吸附量降低36%;HAS-G体系的最终渗吸采收率为24.95%,较地层水渗吸采收率提高10.89%。

Imbibition replacement is an effective way of oil displacement in ultra-low permeability reservoirs.The development of highly efficient imbibition agent can greatly improve oil recovery.HAS-G system was obtained by mixing heavy alkyl benzene sulfonate surfactant HAS-6 with fatty alcohol polyoxyethylene ether surfactant G12-7N according to the ratio of 9∶1,and its interfacial properties,emulsifying properties,static adsorption properties and imbibing properties were evaluated.The results show that the interfacial tension between HAS-G system and dehydrated crude oil in block Y of Changqing oilfield can reach 6.9×10^(-3) mN/m at the optimal concentration of 0.3%.HAS-G system can modify the oil-wet mica sheet to the water-wet state,and the contact angle is reduced from 115°tO66.9°.The emulsion composite index of HAS-G emulsion after standing for 1 h was 0.11.The static adsorption capacity of HAS-G system was 9.3675 mg/g,which was 36%lower than that of HAS-6 system.The final imbibition recovery of HAS-G system was 24.95%,which was 10.89%higher than that of formation water imbibition recovery.