包载驱油表面活性剂智能微胶囊的制备及性能研究

Abstract: The surfactant plays an important role in the chemical enhanced oil recovery (EOR) processes, and it has been attracted significant attention in tertiary oil recovery. However, high adsorption of surfactants onto rock/clay/sediment solid matrix results in the loss and reduction of their concentrations in surfactant flooding, which may render them less efficient or ineffective in practical applications of EOR techniques. Therefore, loss of surfactant due to adsorption on porous media can make the chemical EOR processes economically unfeasible. This topic proposes a novel surfactant flooding included monodisperse smart microgels encapsulated surfactants, which can decrease adsorption of surfactants on reservoir rock dramatically and enhance oil recovery effectively. This topic will focuse on the controllable preparation of monodisperse smart microgels, and investigate valid encapsulated and thermo-responsive controlled release of surfactants. In this study, the effects of smart microgels on flooding fluid properties and the decrease adsorption of surfactants on reservoir rock and the regularity of oil displacement effectiveness will be systematically investigated. The results will present a novel possibility for surfactant flooding system, and it deserves a promising future in wide application in oilfields and has highly social benefits.

摘要：在化学驱油过程中，表面活性剂起着非常重要的作用，已成为三次采油的研究热点。然而表面活性剂在地层岩石中强烈的吸附滞留致使损耗量大，影响提高采收率，带来比较高的成本问题。本课题提出一种新型的将驱油表面活性剂包载于智能微胶囊空腔内的驱油体系，能有效解决表面活性剂的吸附损失问题从而提高采收率。课题重点研究智能微胶囊的可控制备，考察其对驱油表面活性剂的有效包载和可控释放，研究微胶囊对驱油体系流体性质的影响以及避免表面活性剂吸附损失提高采收率的规律。研究结果将为改进现有表面活性剂驱油体系开辟一条新的途径，具有显著的社会价值和广阔的应用前景。

随着石油储量的日益减少，如何提高原油采收率变得愈发重要。表面活性剂以其能大幅度降低油水界面张力、改变岩石表面润湿性等优良特性，在三采领域有着广泛的应用。但在地层运移过程中，表面活性剂会与地层岩土产生吸附作用，从而导致浓度下降。强烈的吸附滞留问题导致表面活性剂损耗量大，降低驱油效率，带来比较高的成本问题。避免表面活性剂的吸附损失，是三采领域面临的一个重要问题。.本研究通过控制与N-异丙基丙烯酰胺共聚的亲水单体的种类及加量，制备出了具有不同VPTT的温敏亚微球。研究了阴离子型、阳离子型和非离子型三种不同类型的表面活性剂对PNIPAM温敏特性的影响。基于微流控技术，以制备的单分散 O/W/O 乳液为模板，制备了以N-羟甲基丙烯酰胺为壁材的微胶囊。并考察了反应时间、内水相和中间油相密度对微胶囊的影响。根据Fick 第一扩散定律，建立了表面活性剂扩散模型，分别测定了不同交联度以及不同壁厚的微胶囊的渗透系数。结果表明，随着囊壁厚度的减小或囊壁交联度的减小，其渗透系数也相应的增大。最后本研究设计并制备了一种温度响应型智能微胶囊，制备的微胶囊具有良好的温度响应性，能通过改变环境温度改变微胶囊的渗透系数。对阴离子表面活性剂SDBS包载释放实验结果表明，微胶囊在环境温度高于温敏亚微球VPTT的条件下，表现出更快的表面活性剂的释放速度。而随着亚微球加量的增加，微胶囊的渗透系数也逐渐增大。