【作者】 张磊；

【导师】 赵濉； 张路；

【作者基本信息】 中国科学院研究生院（理化技术研究所） ， 物理化学， 2008， 博士

【摘要】 近年来,随着理论模型和实验技术的进展,界面扩张流变研究逐渐成为界面膜性质研究的一大热点。界面扩张流变性质的研究有助于加深对界面膜微观结构的认识,对阐明乳状液稳定及破乳机理有重要意义;可以更深刻地反映与强化采油相关的界面现象的内在规律;有助于了解表面活性剂分子在界面上的吸附及其相互作用,进而阐明界面张力机理。本论文针对复合驱油过程中的特殊界面现象,采用Langmuir槽和气泡/液滴扩张两种技术,运用小幅低频振荡和界面张力弛豫分析方法,系统研究了表面活性剂的扩张流变性质以及驱油体系化学剂和有机活性组分间相互作用对扩张性质的影响,主要研究内容和取得的主要创新性成果如下:首先,利用气泡/液滴振荡技术和表面/界面张力弛豫方法系统研究了实验室制备的25种高纯度烷基苯磺酸盐的表面和界面扩张性质,考察了工作频率、表面活性剂体相浓度、疏水链长度、疏水链支化程度、苯环上烷基的多取代等因素对扩张性质的影响,获得了表面/界面微观弛豫过程的特征参数,探讨了表面活性剂结构与扩张参数的关系。研究结果表明,表面活性剂结构直接决定其界面行为,烷基取代在苯环的不同位置对扩张流变性质影响不同,并且导致所形成的表面的吸附膜和界面吸附膜各有异同。间位和对位双取代长直链类型具有最高的表面扩张参数;对位或间位取代长支链具有最高的界面扩张参数。之后,选择了两种有代表性的驱油表面活性剂模型化合物(多取代烷基苯磺酸钠和Gemini表面活性剂)、两种不同结构的典型驱油聚合物(超高分子量聚丙烯酰胺和疏水改性聚丙烯酰胺)、两类代表性原油活性组分模拟化合物(长链酸和长链醇)以及三种电解质(钠盐、镁盐和钙盐),利用基于Langmuir槽滑障机械振荡的界面扩张流变仪,采用小幅低频振荡和界面张力弛豫技术,系统研究了水相中不同结构表面活性剂、聚合物、电解质以及油相中长链酸、长链醇之间相互作用对界面扩张流变特性的影响,考察了不同浓度稀释原油与化学驱体系的界面扩张性质。研究发现:表面活性剂可以和聚合物形成混合吸附膜或和疏水嵌段形成类似于胶束的混合聚集体,从而改变界面扩张性质。电解质通过改变离子表面活性剂分子间的静电作用,影响界面的扩张性质。少量的表面活性有机物可以和表面活性剂分子形成混合吸附膜,使模量略有增强;而大量的表面活性有机物,可能破坏表面活性剂疏水长链之间原有的强相互作用,使得扩张模量大大降低。原油中沥青质等活性组分具有较强的分子间相互作用,模量较大,表面活性剂与之形成混合吸附膜,使扩张模量略有升高;而聚合物的存在可能破坏了原油活性组分间的强相互作用,界面扩张模量明显降低。研究结果表明,界面扩张流变研究是探索表面/界面膜结构的有力手段。更多还原

【Abstract】 With the developments of the theoretical model and the experimental technology, the research of the interfacial dilational rheology has become one of the research hotspots of the interfacial film properties in recent years. The study of the dilational rheology can make contribution to the more profound understanding of the microscopic structure of the interface, which is significant for elucidating the stability and demulsification mechanism of the emulsion, and may be deeply reflecting the internal law of the interfacial phenomenon as related to EOR. Moreover, the measurements of dilational properties are helpful to elucidate the mechanism responsible for lowering IFT due to the adsorption behavior of the surfactant and the interaction among surfactant molecules.In this paper, the dilatational viscoelastic properties have been investigated by means of Langmuir trough method or oscillating bubble/drop method. Two different techniques, sinusoidal oscillations and interfacial tension relaxations, have been used to study the dilational properties of the surfactant solutions and the EOR systems. The experimental results are as following:Firstly, the dilational viscoelastic properties of twenty-five types of alkyl benzene sulfonates with high purity, which were synthesized in our laboratory, were investigated by oscillating bubble/drop method and surface/interfacial tension relaxation method at air-water and decane-water interfaces. The effects of the frequency, bulk concentration, hydrophobic chain length, the degree of the branch of hydrophilic group and the position of hydrophobic chains located in the benzene ring were investigated. Interfacial tension relaxation method was employed to obtain the characteristic parameters of the micro-relaxation process. A correlation between the surfactant structure and dilational parameters has been discussed. It showed that the surfactant structure directly determines interfacial behavior. It is worth noticing that hydrophobic chains located in the different positions of the benzene show different effects on dilational properties, and leads to different behavior when the upper phase is decane. The surfactants with bi-substituted long straight meta-alkly and para-alkly show higher surface dilational parameter values, while the surfactants with long branched chain oriented para and meta of the benzene have the maximum interfacial dilational parameters.Secondly, the two representative surfactants in EOR ( multi-n-alkylbenzene sulfonates and Gemini surfactant), two typical flooding polymers (ultrahigh molecular weight polyacrylamide and hydrophobic modified polyacryamides), two kinds of organic active components ( long-chain acid and long-chain alcohol ) were selected as model compounds of EOR systems. The effects of different surfactant structure, polymer, electrolyte, long-chain acid, long-chain alcohol and diluted crude oil on the dilational properties were expounded by Langmuir through method. It was found that the surfactant may form mix-adsorption layer with polyacrylamide or form mixed complexes with hydrophobic block of hydrophobic modified polyacryamide at the interface, thus influences the interfacial dilational properties. The electrolyte can affect the viscoelastic properties of the adsorbed layer by changing the electrostatic interaction among the ionic surfactants. A small quantity of organic surface-active component may enhance the dilational modulus by forming densely packed mixed-adsorption layer with surfactant through hydrophobic interaction, while the superfluous addition of surface-active components could sharply decrease the dilational modulus mainly due to the weakening of the strong interfaction among long alkyl chains in surfactant molecules. The diluted crude oil has higher dilational parameter values due to the strong interactions existing in the active component, such as asphaltene. The surfactants increase the dilational modulus and dilational elasticity of the crude oil via forming a mixed-adsorption layer. However, the polymers weaken the strong interactions of the crude oil molecules and decrease the interfacial dilational modulus.Our results show that the measurement of interfacial dilational properties is a powerful method to probe the structure of adsorption film.更多还原