三元复合驱对砂岩储层的影响

发布时间：2018-06-10 13:39

本文选题：三元复合驱 + 碱岩反应　；参考：《西南石油大学》2017年硕士论文

【摘要】：我国东部油田的主要产油层位基本都为碎屑岩储层。经过几十年的勘探开发,目前均到了开发后期阶段,为了油田可持续发展,稳定产量,大庆油田在开发工艺上不断进取,在聚合物驱技术的基础上,为进一步提高采收率,开始研究三元复合驱技术,并对其驱油机理进行了研究,随后开展先导性试验,实验结果表明,三元复合驱的驱油效率可将油田的采收率平均提高20%左右。但对于碎屑岩储层而言,只要在这一体系中有强碱或者弱碱的加入,都必然和储层的物质发生化学反应,因而在驱替过程中不可避免的会出现溶蚀与沉淀作用。这些作用将会影响储层的物性、孔隙结构等方面,从而对储层造成伤害,影响体系的驱替效果。本文以三元复合驱的结垢问题作为切入点,将地质与化学相结合,采用新的试验方法模拟出真实地下条件,在这种条件下进行了单矿物静态浸泡实验以及岩心动态驱替实验。在静态实验中通过使用723型自动分光光度计对反应液进行了实时的硅元素浓度检测,分析对比了各单矿物在碱液中的反应机理及强度。另一方面对岩心进行驱替实验并收集了油田试验区驱替前后的岩心,以扫描电镜法、铸体薄片法、压汞法、X衍射法分析了三元驱替前后岩心各方面的变化情况,并详细研究了碱岩反应规律,对垢质的形成原因、条件、过程、时间、析出顺序等方面进行了探讨,结果表明:(1)粘土矿物中的蒙脱石和高岭石与碱的反应最为剧烈;(2)当地层水中钙离子浓度过高,三元复合剂进入储层后会与之反应生成大量钙质垢,尤其是弱碱复合驱替剂;(3)三元驱后岩心矿物成分有所变化,高岭石、蒙脱石、石英等都发生了不同程度的溶蚀,产生了大量硅酸离子,它们随流体流动并聚集,在后期形成一种无定形的硅胶,以络合物的形式从溶液中沉淀出来,并在运移一定距离后遇到较小孔喉而发生沉降,使储层非均质性加强。根据以上实验结果,本文建立了三元复合驱过程中砂岩储层溶蚀与沉淀的反应机制,探索出了结垢规律,为三元复合驱的进一步发展提供基础理论和可靠的地质依据。
[Abstract]:The main oil-producing reservoirs in the eastern oil fields of China are basically clastic reservoirs. After decades of exploration and development, at present, all of them have reached the late stage of development. For the sake of sustainable development and stable production of oil fields, Daqing Oilfield is constantly making progress in the development process, and on the basis of polymer flooding technology, in order to further improve oil recovery, The ASP flooding technology is studied, and the oil displacement mechanism is studied. Then the pilot test is carried out. The experimental results show that the oil displacement efficiency of ASP flooding can increase the oil recovery by about 20% on average. But for clastic rock reservoir, as long as there is strong alkali or weak alkali in this system, the chemical reaction will take place with the material of the reservoir, so the dissolution and precipitation will inevitably occur in the displacement process. These effects will affect the physical properties, pore structure and other aspects of the reservoir, thus causing damage to the reservoir and affecting the displacement effect of the system. In this paper, the scaling problem of ASP flooding is taken as the starting point, combining geology with chemistry, and the real underground conditions are simulated by a new test method. Under this condition, the static soaking experiments of single minerals and the dynamic displacement experiments of cores are carried out. In the static experiment, the concentration of silicon element in the reaction solution was measured in real time by using 723 automatic spectrophotometer, and the reaction mechanism and intensity of each single mineral in alkali solution were analyzed and compared. On the other hand, the core displacement experiment was carried out and the core before and after displacement was collected in the oil field experimental area. The changes of core before and after ternary displacement were analyzed by scanning electron microscopy, casting thin slice method, mercury injection method and X ray diffraction method. The reaction law of alkali rock is studied in detail, and the formation reason, condition, process, time and precipitation sequence of scaling are discussed. The results show that montmorillonite and kaolinite in clay minerals react most intensely with alkali. (2) the concentration of calcium ions in the local water is too high, and when the ternary compound agent enters the reservoir, it will react with it to form a large amount of calcareous scale. In particular, the mineral composition of the core has changed after the ternary flooding of the weak base compound flooding agent, Guan3). Kaolinite, montmorillonite, quartz and so on have been dissolved to varying degrees, resulting in a large amount of silicate ions, which flow and accumulate with the fluid. In the later stage, an amorphous silica gel is formed, which is precipitated from the solution in the form of complex compounds, and then subsidence occurs after a certain distance of migration, which strengthens the heterogeneity of the reservoir. Based on the above experimental results, the reaction mechanism of dissolution and precipitation in sandstone reservoir during ASP flooding is established, and the scaling law is explored, which provides basic theory and reliable geological basis for the further development of ASP flooding.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE357.46

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