大庆油田三元复合驱液与储层矿物反应性研究

三元复合驱技术能够显著提高石油的采收率,但在生产过程中三元复合注入液易与储层矿物反应,破坏储层并结垢,造成井下堵塞、采收率降低等问题,因此研究三元复合驱液在储层中的溶、运、堵过程及反应机理成为当务之急。本文利用X射线衍射(XRD)、X射线光电子能谱(XPS)、场发射环境扫描电镜(ESEM)及X射线能谱仪(EDS)测试手段精细表征了大庆油田储层矿物钾长石、石英、高岭石与强碱三元复合驱液作用的反应过程及变化特征,并通过反应动力学计算得到了相应的Si、Al溶出动力学方程及矿物溶蚀再沉积规律,深入探讨了反应机理。结果显示,钾长石与强碱复合驱液作用60 d后Si溶出量约为Al的3倍,生成三水铝石和硅酸盐沉淀物;石英的Si溶出量呈线性增加,60 d后超过300×10-6,表面生成碳酸盐颗粒;高岭石60 d后Al溶出量约为Si的3倍,结晶度下降25.26%,生成水钙沸石;强碱对矿物的溶蚀破坏程度与其浓度呈正相关。

A study of the reaction of alkali/surfactant/polymer and reservoir minerals in the Daqing oilfield

The alkali/surfactant/polymer(ASP) flooding technology can significantly enhance oil recovery. Nevertheless, the ASP injection fluid can easily react with reservoir minerals during the productive process which could do harm to reservoir strata and scale, resulting in plugging underground, reduction of the recovery rate and other technical problems. Therefore, the study of dissolution, transportation and plugging process and reaction mechanism of ASP in reservoir becomes a pressing matter of ASP flooding technology. The reaction process of ASP and reservoir minerals including potassium feldspar, quartz and kaolinite and minerals'' changing characteristics in the Daqing oilfield were analyzed in detail through some testing means such as X-ray Diffraction(XRD), X-ray Photoelectron Spectroscopy(XPS), Field Emission Environmental Scanning Electron Microscope(ESEM) and Energy Dispersive Spectroscopy(EDS). The study of alkali dissolution reaction kinetics was conducted. And the Si and Al''s dissolution kinetics equations of reservoir minerals indicating ions'' dissolution and reprecipitation rules were calculated. Finally the reaction mechanism of ASP and reservoir minerals was analyzed. The results show that the dissolved amount of Si in potassium feldspar is three times that of Al after the interaction with ASP for 60 days. Gibbsite and some kinds of silicates are formed. The dissolved amount of Si in quartz increases linearly and exceeds 300×10^-6 after the interaction with pure alkali and ASP for 60 days. Carbonate particles are formed on quartz crystals'' surfaces. The dissolved amount of Al in kaolinite is three times that of Si and the crystallinity of kaolinite decreases by 25.26% after the interaction with ASP for 60 days. Gismondine is formed. The corrosion and damage extent of reservoir minerals by alkali is positively correlated with alkali''s concentration.