破乳剂与驱油表面活性剂在油滴表面竞争性吸附及破乳机理研究

The alkali/surfactant/polymer (ASP) flooding is a kind of economical and efficient enhancing flooding technology. However, flooding technology is not used widely because the produced water by ASP flooding is difficult to separate. The produced water by ASP flooding have some characteristics, such as high strength of oil-water interfacial film, highly emulsified and easy to re-emulsified. In order to address these issues, the stability of oil-water interfacial film of the simulated produced water by ASP flooding will be investigated. The adsorption performance of surfactant on the surface of oil droplet will be investigated using theory of interface chemistry, testing technology of interface, microcalorimetry technology and molecular dynamics simulation. The effect and mechanism of surfactant molecular structure on the stability of oil-water interfacial film and microscopic performance will be revealed. The new method for demulsifier molecular design will be proposed based on the synergistic reaction of demulsification and adsorption，the reversed demulsifier of polyether and polyquaternary ammonium-coated hydrated silicon ( PPA@SiO2) was prepared using polyether and polyquaternary ammonium surface graftd with hydrated silicon polymerization. The demulsification mechanism will be revealed by investigating the competitive adsorption between the reversed demulsifier of polyether and polyquaternary ammonium-coated hydrated silicon and flooding surfactant on the surface of oil droplet. The synergistic mechanism of demulsification and adsorption will be established in the demulsifying process using polyether and polyquaternary ammonium-coated hydrated silicon reversed demulsifier. The results of this proposed project will provide theoretical direction and application value for developing some new demulsifiers.

三元复合驱是一种高效经济的强化采油技术，但由于三元复合驱采出水界面膜强度高、含油乳化程度高，大量驱油表面活性剂的存在导致破乳过程具有可逆性，相态稳定难破乳，处理难度大，限制了该技术大规模推广应用。本项目针对这一破乳难题，从模拟三元复合驱采出水界面膜稳定性认知入手，采用界面化学理论与测试技术、微量热测试技术以及分子动力学模拟从微观层面研究表面活性剂在油滴表面吸附规律，揭示表面活性剂分子结构对油‐水界面膜稳定性与微观行为影响的机理。提出基于破乳与吸附协同作用的破乳剂分子设计新思路，采用表面接枝聚合法合成兼具破乳与吸附功能的负载型聚醚聚季铵盐反相破乳剂。通过负载型聚醚聚季铵盐反相破乳剂与驱油表面活性剂在油滴表面竞争吸附行为研究，揭示破乳机理，建立负载型聚醚聚季铵盐反相破乳剂的破乳与吸附过程的协同作用机制。研究结果对于新型破乳剂的开发具有理论意义和实际应用价值。

三元复合驱的原油采收率比普通水驱提高20个百分点以上，保障了油田稳产增产，同时也产生了大量三元复合驱采出水。三元复合驱采出水含油乳化程度高、微细粒径油滴含量高，处理难度大，微细油滴破乳脱稳是提高油水分离效率的关键。该项目在研究三元复合驱采出水稳定性机制基础上，开发了集破乳、吸附于一体的新型破乳剂，研究成果对于解决三元复合驱采出水高效破乳、避免二次乳化问题具有重要的理论意义和应用价值。. 主要研究内容包括：. 1）三元复合驱采出水油/水界面膜稳定性研究；2）聚醚聚季铵盐负载型破乳剂合成、表征及性能评价；3）聚醚聚季铵盐及其负载型破乳剂破乳机理研究；4）聚醚聚季铵盐负载型破乳剂破乳后载体颗粒对油滴的吸附特性与机理。. 该研究主要创新为：. 1）理念创新。基于三元复合驱采出水中驱油表面活性剂和破乳剂在油滴表面竞争性吸附，破乳、乳化过程共存、可逆的稳定性特征和微细油滴尺寸效应，提出了破乳与吸附协同作用的破乳剂分子设计新思路。 . 2）基础研究。采用高速显微成像、分子模拟和吸附热测试相结合分析了油/水界面膜薄化行为、驱油表面活性剂在油滴表面吸附行为和吸附热效应，首次从微观层面揭示了三元复合驱采出水油/水界面膜稳定性机制；分析了破乳过程油/水界面膜薄化行为、基于AFM油膜形貌与界面膜弹性模量变化规律、破乳剂和驱油表面活性剂竞争吸附热效应及负载型破乳剂破乳前、后分子结构变化，揭示了聚醚聚季铵盐及其负载型破乳剂顶替置换破乳机理；揭示了聚醚聚季铵盐及其负载型破乳剂电中和破乳机理；分析了载体颗粒吸油动力学、热力学与吸附热效应，提出了聚醚聚季铵盐负载型破乳剂破乳过程与吸附过程协同作用机制。. 3）药剂开发。采用表面接枝聚合法合成新型聚醚聚季铵盐负载型破乳剂、聚醚季铵盐负载型破乳剂和聚醚接枝ZIFs负载型破乳剂，将聚醚聚季铵盐及其负载型破乳剂应用于三元复合驱采出水处理的现场试验中，处理后出水平均含油浓度为30.59 mg/L，平均脱油率达到89.76%。