低矿化度水驱油机理研究

发布时间：2018-01-16 12:30

本文关键词：低矿化度水驱油机理研究　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：低矿化度水驱油是指向油藏注入含有低浓度可溶性固体的水的驱替方法。低矿化度水驱油可以大幅度提高原油采收率,对油田的未来发展具有重要意义。本文以低矿化度水驱油的理论基础为核心,通过测定低矿化度水驱油体系的Zeta电位,得到了砂岩储层中低矿化度水驱油提高采收率的主要机理。确定了影响低矿化度水驱油采收率的主要因素,并总结了低矿化度水驱油的产生条件,即储层岩石中含有粘土矿物、原油中含有极性组分、地层水中含有高价阳离子、注入水的矿化度在一定的范围内。根据胶体化学理论,测定了油-岩石和水-岩石的Zeta电位。结果表明,随着注入水矿化度的降低,界面间的斥力增大,扩散双电层厚度增加,Zeta电位的绝对值增加。通过原油吸附实验和接触角实验的佐证可得,随着矿化度的降低,粘土矿物表面扩散双电层的厚度也随之增加;阳离子通过离子交换作用,把吸附在粘土矿物表面的有机极性物质取代,使其解吸,最终令粘土矿物表面更加水湿。通过室内模拟实验,开展了低矿化度水驱油实验,结果表明,低矿化度水驱的采收率要比地层水驱替的采收率高10%左右;低矿化度NaCl驱替的采收率高于低矿化度CaCl2。研究了低矿化度水驱油机理,探讨了低矿化度水驱油提高采收率的其他机理,包括类表面活性剂和提升pH值等。
[Abstract]:Low salinity water flooding is a method to inject water containing low concentration of soluble solids in a reservoir, and low salinity water flooding can greatly improve oil recovery. This paper is based on the theoretical basis of low salinity water flooding, through the determination of low salinity water flooding system Zeta potential. The main mechanism of improving oil recovery by low salinity water flooding in sandstone reservoir is obtained. The main factors affecting oil recovery of low salinity water flooding are determined, and the production conditions of low salinity water flooding are summarized. That is, the reservoir rocks contain clay minerals, the crude oil contains polar components, the formation water contains high valence cations, and the salinity of injected water is within a certain range, according to the colloidal chemistry theory. The Zeta potential of oil-rock and water-rock is measured. The results show that with the decrease of the salinity of injected water, the repulsion force between the interfaces increases and the thickness of the diffusion double electric layer increases. The absolute value of Zeta potential is increased. The thickness of diffusion double electric layer on clay mineral surface increases with the decrease of salinity through the experiments of crude oil adsorption and contact angle. By ion exchange, the organic polar substance adsorbed on the surface of clay minerals is replaced by cations to desorb them, and finally make the surface of clay minerals more water and wet. The results show that the oil recovery of low salinity water flooding is about 10% higher than that of formation water flooding. The oil recovery of low salinity NaCl flooding is higher than that of low salinity CaCl 2. The mechanism of low salinity water flooding is studied, and other mechanisms of improving oil recovery by low salinity water flooding are discussed. It includes surfactants and pH.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE357.6

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