三元复合驱驱油效率影响因素研究

【作者】 唐钢；

【导师】 李华斌；

【作者基本信息】 西南石油学院 ， 油气田开发工程， 2005， 硕士

【摘要】 碱/表面活性剂/聚合物三元复合驱是既可以提高油层波及体积又能提高驱油效率的三次采油方法,作为油田开发提高采收率的一种重要技术手段,已经进入工业化应用阶段。复合驱油技术具有投资高、技术难度大和经济风险大的特点,其在矿场实施的效果取决于多种因素,包括油藏地质特征、油水界面张力、油层润湿性以及复合体系的吸附滞留损耗等因素。 本文从复合驱驱油机理研究出发,考察了复合驱驱油体系的流变学性质和它们之间的协同效应,并从理论上探讨了影响复合驱驱油效率的几个重要因素。在此基础上,以大庆油层条件为例,通过室内实验考察了五种复合体系与大庆原油间的界面张力性质,筛选出三种不同界面张力数量级的驱油体系,并进一步通过岩芯驱油实验探询三元复合驱中驱油效率与油层渗透率、体系界面张力之间的相互关系。研究表明:界面张力是复合驱大幅度提高采收率的主要因素;复合体系与原油间的界面张力值,包括平衡和瞬时动态界面张力值对于复合驱的驱油效果有显著的影响;油水界面张力降低到10^-3mN/m数量级是三元复合驱大幅度提高采收率的充分条件,而不是必要条件;油层岩石润湿性对岩芯的饱和程度以及复合驱采收率都有明显影响,随着润湿接触角的增大,复合驱采收率明显增加;在化学剂组成和浓度相同的情况下,中等渗透率的岩芯的驱油效率更高些。更多还原

【Abstract】 The alkali/surfactant/polymer（ASP） flooding is generally considered as a new technology that not only increase sweep efficiency but also improve displacement efficiency, and that it is regarded as a very important technology in EOR process and have awarded tremendous success both in pilot test and industrialized application stages. The ASP flooding technology specialities in high cost, technological difficulty and have big risk economically. The success application of ASP flooding depend on multifarious factors, including geological feature of the reservoir and interfacial tension between oil and water and wettability as well as displacing fluids loss caused by adsorption and detention, etc.The thesis researches on the properties and synergetic effects of ASP chemical agents on the basis of the flooding mechanism of ASP flooding, and then discusses theoretically about the influencing factors of displacing efficiency in ASP flooding process. Under Daqing reservoir conditions, we research on properties of interfacial tension between five different kinds of ASP chemical system and crude oil, and screen out three kinds of chemical systems that have different order of magnitudes of interfacial tension, and then we carry out core flooding experiment both on heterogeneous and homogeneous synthetic cores and discuss about the correlation among permeability, interfacial tension, wettability and displacing efficiency in ASP processes. The result demonstrates: interfacial tension is the primary factor that improves displacing efficiency in ASP flooding; the interfacial tension between the ASP chemical system and the oil, including balance and instantaneous dynamic interfacial tension, make remarkable influence on displacing efficiency in ASP flooding process; the balance interfacial tension between oil and water falls to the level of 10^-3mN/m is only a sufficient condition but not a necessary condition for enhancing the oil recovery greatly; the wettability of the rock makes an obvious influence on saturation degree of core as well as ASP flooding efficiency. With the increase of the wetting contact angle, the displacement efficiency increases obviously in ASP flooding process; under the condition that the composition and concentration of chemical agents, the displacement efficiency is a bit higher in the core of moderate permeability.更多还原