Abstract: The scale deposit in oil strata and bottom of oil wells is a great trouble in situ tests of alkaline-surfactant-polymer (ASP) flooding area of Daqing Oilfield.In order to confirm the factors affecting the scaling,the dynamic and static water-rock reaction simulation tests for alkali,surfactant,polymer and their compound system were carried out under the relative conditions based on the properties of stratum rocks and fluid in the test area.A predictive model for silica scaling was established according to the solubility product theory.The model was used to predict the quantity of silica scaling in the test site of Xingbei Oilfield in Daqing area.The results show that the alkali in the ASP solution system makes evident denude effect to oil stratum rocks,which enforces some ions forming silica scale,such as Si⁴⁺、Al³⁺、Ca²⁺、Mg²⁺ ions.Those ions enter into solution and form amorphous SiO₂ in some specific conditions.The analytical results on some scaling samples collected in situ show that the values of prediction and practice are consistent.This prediction method can be used to select quality of water injected into oilfield for reducing damage of storing oil strata.

Key words: alkaline-surfactant-polymer compound flooding, silica scaling, scale forming mechanism, prediction method, Daqing Oilfield

摘要： 油层内及油井底结垢是大庆油田三元复合驱现场试验过程中须解决的一个重大问题.基于试验区地层岩石及流体特点,对碱、表面活性剂、聚合物及三元复合体系在相关条件下的动态、静态水-岩反应进行了模拟试验,以确定这些因素对成垢作用的影响.在此基础上,根据溶度积理论建立了结垢预测模型,运用该模型对大庆杏北油田三元复合驱试验区进行了结垢定量预测.研究表明,三元复合体系中的碱对储层岩石产生了明显的溶蚀作用,使Si⁴⁺、Al³⁺、Ca²⁺、Mg²⁺等成垢离子进入溶液,在特定条件下形成了非晶质SiO₂垢等.对现场采集垢样的检测分析表明,预测结果与实际情况基本吻合.该预测模型可用于选择油田注水水质、减少对储层的损害.

关键词: 三元复合驱, 硅垢, 形成机理, 预测模型, 大庆油田