三元复合驱注入液与储层岩心矿物相互作用的碱耗动力学研究

Study on the Alkali Consumption Kinetics of the Interaction between the Injection Flu⁃id of ASP Flooding and Reservoir Core Minerals

为探索三元复合驱注入液与油藏矿物的相互作用对采出液的影响,实验研究了大庆油田三元复合驱注入液与油藏矿物相互作用过程中的碱耗动力学模型。将储层岩石粉末在45℃条件下浸泡于模拟三元复合驱注入液中,对不同浸泡时间的上清液进行取样分析,结合不同pH值下溶液中各离子的存在情况分析,认为OH-的准确浓度无法通过酸碱滴定法获得,可采用检测Al、Si元素浓度,再推导溶液中剩余OH-浓度的方法进行间接计算。获取不同时间上清液中的OH-浓度,建立三元复合驱注入液与大庆油田北一区断东区块目的油藏岩心矿物反应过程中的碱耗动力学方程,符合v=KCn形式,反应级数为2.6。该结果有助于更深入地理解三元复合驱注入液与油藏矿物的相互作用机制,为优化三元复合驱注入方案提供理论依据。

In order to investigate the effects of products generated during the interaction between oil reservoir minerals and injection fluid of ASP flooding on the composition of produced fluid,the alkali consumption kinetic model during the interaction is investigated.The powder samples of the oil reservoir minerals are soaked in simulated ASP flooding injection fluid at 45℃for different time intervals,and samples of the supernatant are taken for analysis.Based on the analysis of the presence of various ions in the solution under different pH values,it is found that the accurate concentration of OH-ions cannot be obtained through acid-base titration.Therefore,a method is proposed to detect the concentrations of Al and Si elements,and then calculate the remaining OH-concentration indirectly.The OH-concentrations in the supernatants at different time intervals are obtained,and the alkali consumption kinetic equation during the reaction process between the injection fluid of ASP flooding and the core minerals of the target reservoir in the Duandong Block of North-1 District in Daqing Oilfield is established,which conforms to the form of v=KCn with a reaction order of 2.6.This result can help better understand the interaction mechanism between ASP flooding injection fluid and the oil reservoir minerals,which provides theoretical basis for optimizing the ASP flooding injection plan.