驱油用黏弹性表面活性剂溶液性能研究

发布时间：2018-04-05 10:21

  本文选题：复配体系　切入点：黏弹性　出处：《西南石油大学》2015年硕士论文

【摘要】：表面活性剂驱作为一种重要的提高采收率方法,其主要通过降低油水界面张力、改善岩石表面润湿性、形成微乳液等提高采收率。目前常规的表面活性剂控制流度能力差,聚表二元体系无法有效避免色谱分离现象,黏弹性表面活性剂(VES)弥补了其缺点,既有增黏性、又能降低油水界面张力,使得驱油效率、波及系数增加。本文通过对以阴离子表面活性剂(AT)为主剂分别与阳离子表面活性剂(CA)、两性离子型表面活性剂(BET)进行复配筛选,确定了VES04和VES05两个体系,并以韦2、沙7区块为背景,研究了浓度、矿化度、温度等因素对其流变性、聚集特征、油水界面张力、长期稳定性及乳化性能的影响。 根据筛选原则,VES04.VES05溶液分别以3：7、27：73的比例复配时体系性能优良,正交实验表明浓度、温度分别对VES04.VES05溶液黏度影响最大,重复实验也己验证,65℃时黏度达到20mPa·s;剪切稳定性研究中,两种溶液均呈现剪切变稀现象,剪应力不断增加；黏弹性特征明显,流体类型都是假塑性流体,松弛时间随浓度的增加分别增加、减小。通过环境扫描电镜发现,VES04.VES05溶液链节之间相互交叠,有不规则的网状结构出现,而加入无机盐后观察到,分子结构破碎分布,规整度低；运用吊片法确定了溶液的临界胶束浓度(CMC),并计算了表面张力γCMC、降低表面张力效率pC20、饱和分子面积Amin和最大吸附量Γmax等表面性质参数。动态光散射研究表明,蒸馏水配置的VES04.VES05溶液的粒径分别是237.14nm、96.7nm；模拟水配置的的VES04、VES05溶液的粒径有所增加. 不同浓度的VES04.VES05溶液与韦2、沙7原油在油藏温度下油水界面张力能达到10-2或10-3数量级,表现出良好的降低界面张力的能力；长期耐温抗盐稳定性研究中,随着老化时间的增加,不同浓度的VES04.VES05溶液黏度均先减小后基本不变,老化后黏度保留率都在65%以上,4000mg/L的VES04溶液、3000mg/L的VES05溶液的界面张力在老化90d后仍然在10-2数量级,表现出良好的耐温抗盐长期稳定性；乳化性能研究中,VES04溶液在油水比为3：7、2：8、韦2与沙7两种原油条件下,析水率均迅速增加,在浓度为4000mg/L时,乳化速率、乳化稳定性较高；VES05溶液在上述条件下,高浓度的溶液析水率较低、乳化速率高、稳定性好；VES04.VES05溶液分别在矿化度为5000mg/L、20000mg/L时乳化稳定性最好；VES04、VES05溶液分别在油水比1：1、3：7时乳化速率最大,在油水比为3：7时乳化稳定性最好。 本论文的研究为韦2、沙7区块进行表面活性剂驱油提供了参考,对油田生产具有一定指导意义。
[Abstract]:Surfactant flooding is an important method to improve oil recovery, which can improve the wettability of rock surface by reducing the interfacial tension of oil and water, forming microemulsion and so on.At present, the conventional surfactants have poor mobility control ability, the binary system can not effectively avoid the phenomenon of chromatographic separation, and the viscoelastic surfactant (VES) makes up for its shortcomings, which not only increases viscosity, but also reduces the oil-water interfacial tension, which makes the oil displacement efficiency.The sweep coefficient increases.In this paper, two systems of VES04 and VES05 were determined by the combination of anionic surfactant (ATT) and cationic surfactant (CAA) and amphoteric ionic surfactant (BET), and the concentration was studied with the background of block Wei 2 and block Sha 7.The effects of salinity, temperature and other factors on rheology, aggregation characteristics, oil-water interfacial tension, long-term stability and emulsification properties.According to the screening principle of VES04.VES05 solution, the properties of the system were excellent when the proportion of VES04.VES05 was 3: 727: 73. The orthogonal experiment showed that the concentration and temperature had the greatest influence on the viscosity of VES04.VES05 solution, and repeated experiments had also verified that the viscosity reached 20mPa s at 65 鈩，

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