鼠李糖脂作为牺牲剂对大庆油田三元复合体系抗吸附性能及驱油效果的评价

Evaluation of Oil Displacement Effect and Anti-adsorption Property of ASP Combination System Taking Rhamnolipid as Sacrificial Agent

强碱三元复合驱技术广泛应用于大庆油田,随着国际原油价格持续走低,降低开采成本成为迫在眉睫的技术难题。为此,研究在三元复合体系中加入适量的廉价牺牲剂,以减少高成本表面活性剂在地层油砂中的吸附损失,进一步提高驱油效率。以生物表面活性剂鼠李糖脂为研究对象,分别采用复配及预吸附的方法,对其改变岩石润湿性、抗吸附及驱油性能进行评价。实验结果表明,鼠李糖脂与烷基苯磺酸盐复配后,二者之间存在着明显的协同效应;鼠李糖脂及其代谢产物可以有效地改变岩石的润湿性,相对润湿指数均由弱亲油性向弱亲水性方向移动;鼠李糖脂可有效降低表面活性剂和碱的吸附损失,可降低表面活性剂吸附损失9.4个百分点,Na OH可减少吸附损失9.8个百分点;在等黏度的驱油条件下,前置段塞注入方式优于复配混合注入方式,前者可使总采收率提高近5个百分点。

The technology of strong alkali-surfactant-polymer（ASP） flooding has been widely used in Daqing oilfield.With the falling of crude oil prices,how to reduce development costs has become an urgent technical difficulty.So,in order to reduce the adsorption loss of high-cost surfactant in oil sand and improve oil dis-placement efficiency,low-price sacrificial agent was added to ASP system.Taking biosurfactant rhamnolipid（RH）as the main research object,its performances of rock wettability changes,anti-adsorption and oil displacement were evaluated by the method of surfactant combination and pre-adsorption.The experiment results show that there are obvious synergistic effect after the rhamnolipid and alkylbenzene sulfonate was combined.Rock wet-tability was changed effectively by rhamnolipid and its metabolites.Relative wettability index was shifted from weak lipophicity to weak hydrophilicity.The adsorption loss of surfactant and alkali（Na OH） could be reduced by 9.4% and 9.8% respectively by the rhamnolipid.The way of pre-slug injection is better than that of mixed injection,and the total recovery efficiency could be increased by nearly 5 percent under oil displace-ment condition with the same viscosity.