油气开采用表面活性剂的合成及性能研究

【作者】 陈洪；

【导师】 罗平亚；

【作者基本信息】 西南石油学院 ， 应用化学， 2004， 博士

【摘要】 提高水驱后剩余油采收率的三次采油研究，已成为油田开发后期加深油田开发的重要课题。化学驱是三次采油的一部分，包括碱驱、聚合物驱、表面活性剂驱和复合驱。复合驱强化采油技术是将碱、表面活性剂、聚合物中的二种或三种组合使用，从而形成二元或三元复合驱技术。它是一种植根于上述几种化学驱技术但又有所革新的技术。虽然复合驱被认为是一种更有潜力的三次采油新方法，但由于目前国内尚未开发出可以降低原油—水界面张力至超低的表面活性剂体系，国外公司虽然开发出了少量品种的可降低油水界面张力至超低的表面活性剂体系，但是这些表面活性价格昂贵且无普适性，而且在使用过程中需要碱的协助，由于碱的影响，复合驱中聚合物的用量也必须相应地增加，这些都将使得开采成本增加，从而在很大程度上限制了复合驱的应用。因此开发和研制出高效实用的表面活性剂具有重大意义。 本文重点对一类结构新型的表面活性剂，阳离子双子表面活性剂(Gemini surfactants)，的表／界面活性以及其溶液的粘度行为作了研究。希望它在性能上可以克服目前油气开采中常用的表面活性剂的不足。 对阳离子双子表面活性剂的表面活性研究发现，双子表面活性剂比普通表面活性剂具有更高的表面活性和更低的临界胶束浓度。双子表面活性剂随着烷基链的增长，临界胶束浓度不断下降，但是当烷基链碳原子数大于16后，其cmc有回升的趋势，联结基对临界胶束浓度的影响比较复杂。双子表面活性剂的临界胶束浓度随着温度的增加而增加。对双子表面活性剂的溶解性的研究发现，T_K与双子表面活性剂的烷基链和联结基的长度有关。对双子表面活性剂的胶团热力学进行了研究，发现胶团的生成是一个熵驱的过程。 研究了双子表面活性剂与煤油以及原油之间的界面张力，发现双子表面活性剂在未加任何助剂的条件下，具有降低油水界面张力至超低的能力。还在不同盐浓度下考察了双子表面活性剂溶液的油水界面张力行为。结果发现，双子表面活性剂具有较高的界面活性，与盐具有很好的协同性，可以在较宽的表面活性剂浓度和盐度范围内很好的降低油水界面张力。 双子表面活性剂的溶液粘度与烷基链和联结基的长度有关。溶液粘度随着双子表面活性剂的烷基链长度的增加而增加，随着联结基长度的增加而下降。研究了双子表面活性剂溶液粘度随温度和时间的变化，发现部分双子表面活性剂的粘度随温度的变化历经一个最大值，以及部分双子表面活性剂溶液的粘度对时间具有明显的依赖性。与有机酸盐按一定比例复合而成的双子表面活性剂体系具有更好的增粘性能，并且在较高温度下粘度能较好的保持。 采用沟槽式界面粘度仪研究了双子表面活性剂和普通表面活性剂的界面粘度。研究发现溶液与油之间的界面粘度主要依赖于表面活性剂与油之间的性质。 通过对双子表面活性剂性能的研究发现，双子表面活性剂在单独使用条件下、并且在较宽的范围内，即可降低油水界面张力至超低。同时双子表面活性剂在稀溶液中还会表现出奇特的粘度行为。因此极有希望将双子表面活性剂作为驱油剂使用，一方面利用它优异的界面活性降低油一水界面张力至超低，另一方面利用它的粘度特征调节水相粘度。也就是说双子表面活性剂驱油体系在取消碱、.聚合物的条件下，仍然有希望达到甚至超过复合驱体系的驱油效率。由于双子表面活性剂驱油体系组成单一，因此在使用时就避免了碱对地层的伤害和色谱分离使得驱油效率降低的问题。关键词:阳离子双子表面活性剂，表面张力，超低界面张力，溶液粘度，界面粘度更多还原

【Abstract】 The tertiary oil recovery research had become important issues, which aimed at improving oil recovery of remainder oil after water flooding or gas injection. Chemical flooding belongs to tertiary oil recovery, which includes alkali flooding, polymer flooding, surfactants flooding and compounds flooding. Compounds flooding were derived from the related chemical flooding and also had innovation. Although compound flooding was regarded as a new potential tertiary oil recovery technique, surfactants systems which can reduce oil-water interfacial tension to ultralow values are not developed in our country. Oversea corporations have developed a few surfactants system, but the prices are very expensive and these surfactants system cannot fit to various crude oil and need the help of alkali. As the influence of alkali, the use of polymers in the compounds flooding could increase, which could increase the costs of oil recovery and to a large extent confine the application of compounds flooding. So the exploration of surfactants system with high effectiveness and practicability has a great significant.This paper focused on the research of surface (interface) activity and solution viscosities of a new class of surfactants, gemini surfactants, and wished them overcoming the defects of common surfactants.Gemini surfactants have much higher surface activity and lower critical micelle concentration than corresponding conventional surfactants. The cmc decreases with the increase of alkyl carbon number, and increased with the increasing of temperature. But if the alkyl carbon number was above 16, the experimental cmc was higher than the expected value. Spacer had a complex influence on the cmc. The Krafft temperature of gemini surfactants is closed related to the alkyl carbon number and the spacer. The micelle thermodynamics studies show that the micellization is an entropy-driven process.The interfacial tension between oil (kerosene or oil) and gemini surfactants solution had been studied. Gemini surfactants solution can reduce the interfacial tension to ultralow values without additives, and Gemini surfactants had good synergistic effect with salts, which could acquire ultralow interfacial tension at a wide range of salt or surfactants concentration.The viscosity of gemini surfactants solution is also related to the alkyl carbon number and the spacer. Viscosities of gemini surfactants solution increase with the increase of alkyl carbon number and decrease with the increase the spacer. Viscosities of some gemini surfactants solution are dependent on time and temperature, which viscosities undergo a maximum with the increase of temperature or decrease with the time going. The mixtures of gemini surfactants and organic acid salts have better viscosification and maintain high viscosities even at high temperature.The interfacial viscosities of oil and gemini surfactants or conventional surfactant had been investigated using deep channel viscous interfacial viscometer. The interfacial viscosities are closely related to the nature of both surfactants and oil.From the research of gemini surfactants solution properties, it can be found that gemini surfactants can reduce the interfacial tension between oil and solution to ultralow. at a wide range without additives, and also appear remarkable viscosities in dilute solution. It is very hopeful to be used as a new series of oil displacement agents, which have both the abilities to reduce interfacial tension between oil and water to ultralow values, and the abilities to modify water phase viscosities. At the nonuse of alkali and polymer, these new oil displacement agents can have an effective oil displacement no less than that of ternary compound flooding. As the singleness of gemini surfactants flooding system component, the oil displacement effectiveness will not be influenced by chromatographic fractionation, and the oil formation harmed by use of alkali will be avoided.更多还原