PDF(Pubmed)
Abstract：
Surfactants adsorption onto carbonate reservoirs would cause surfactants concentrations decrease in surfactant flooding, which would decrease surfactant efficiency in practical applications of enhanced oil recovery (EOR) processes. Different surfactants could be classified as cationic surfactants, anionic surfactants, non-ionic surfactants according to the main charge, or be classified as chemical surfactant and bio-surfactant according to the surfactant origin. However, the research on different type surfactants adsorption on carbonate reservoirs surface differences was few. Therefore, five representative surfactants (CTAB, SDS, TX-100, sophorolipid, rhamonilipid) adsorption effect onto carbonate reservoirs surface was studied. Owing to the fact that the salinity and temperature in underground carbonate reservoirs were high during the EOR process, it is vital to study the salinity effect and temperature effect on surfactant adsorption. In this study, different surfactants species, temperature and salinity adsorption onto carbonate reservoirs were studied. The adsorption isotherms were fitted by Langmuir, Freundlich, Temkin and Linear models, and the first three models fitting effect were good. The results showed that cationic surfactants adsorption quantity was higher than anionic surfactants, and the non-ionic surfactants adsorption quantity was the lowest. When the temperature increased, the surfactants adsorption would decrease, because the adsorption process was exothermic process, and increasing temperature would inhibit the adsorption. The higher salinity would increase surfactants adsorption because higher salinity could compress electric double layer. In order to decrease surfactants adsorption, SiO2 nanoparticles and TiO2 nanoparticles were added to surfactants solutions, and then surfactants could adsorb onto nanoparticles surface, then the steric hindrance between surfactant molecules would increase, which could decrease surfactants adsorption. Contact angle results indicated that surfactants adsorption made the carbonate reservoir wettability alteration. In the end, surfactants (with or without SiO2 nanoparticles) adsorption onto carbonate reservoirs mechanism were studied by molecular dynamics simulation. The simulation results indicated that the surfactants molecules could adsorb onto SiO2 nanoparticles surface, and then the surfactants adsorption quantity onto carbonate rocks would decrease, which was in accordance with the experiments results.
摘要：
表面活性剂吸附在碳酸盐岩储层上会导致表面活性剂驱油中表面活性剂浓度降低，这将降低提高采油率（EOR）工艺的实际应用中的表面活性剂效率。不同的表面活性剂可以归类为阳离子表面活性剂,阴离子表面活性剂，根据主电荷的非离子表面活性剂，或根据表面活性剂的来源分为化学表面活性剂和生物表面活性剂。然而,关于不同类型表面活性剂在碳酸盐岩储层表面吸附差异的研究较少。因此,五种代表性表面活性剂(CTAB，SDS,TX-100，槐糖脂，研究了鼠李糖脂）在碳酸盐岩储层表面的吸附作用。由于在EOR过程中，地下碳酸盐岩储层的盐度和温度很高，研究盐度和温度对表面活性剂吸附的影响至关重要。在这项研究中,不同的表面活性剂种类，研究了温度和盐度在碳酸盐岩储层上的吸附。吸附等温线由Langmuir拟合，Freundlich,Temkin和线性模型，前三个模型拟合效果良好。结果表明,阳离子表面活性剂吸附量高于阴离子表面活性剂,非离子表面活性剂吸附量最低。当温度升高时,表面活性剂的吸附会减少，因为吸附过程是放热过程，温度升高会抑制吸附。较高的盐度会增加表面活性剂的吸附，因为较高的盐度会压缩双电层。为了减少表面活性剂的吸附，将SiO2纳米颗粒和TiO2纳米颗粒添加到表面活性剂溶液中，然后表面活性剂可以吸附到纳米颗粒表面，那么表面活性剂分子之间的空间位阻就会增加，这可能会降低表面活性剂的吸附。接触角结果表明，表面活性剂的吸附使碳酸盐岩储层润湿性发生变化。最后,通过分子动力学模拟研究了表面活性剂（含或不含SiO2纳米颗粒）在碳酸盐岩储层上的吸附机理。模拟结果表明,表面活性剂分子可以吸附在SiO2纳米颗粒表面,然后表面活性剂在碳酸盐岩上的吸附量就会减少，这与实验结果一致。
