Zhang Yong, Zhi Caifu, Qi Jie, Wang Li, Lu Hongsheng, Zhang Zheng, Li Yuzhe
College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, PR China.
School of New Energy and Materials, Southwest Petroleum University, Chengdu 610500, PR China.
Langmuir. 2024 Oct 8;40(40):21232-21240. doi: 10.1021/acs.langmuir.4c02840. Epub 2024 Sep 23.
As a key component of slickwater fracturing fluids, emulsion drag reducers play a vital role. The dissolving capacity of traditional emulsion drag reducers is improved by adding hydrophilic surfactants, which leads to poor stability of the emulsion drag reducer. In order to eliminate the contradiction between stability and release of the emulsion drag reducer, here, pH-responsive polymer emulsion was fabricated using the switching solvent (HA) and white oil as the continuous phase. Monomer emulsions exhibit obvious pH-responsive behavior. This is because the deprotonation of HA by pH stimulation leads to a change in the oil-water ratio of the emulsion, thereby facilitating the demulsification of emulsion. The remarkable stability of the monomer emulsion benefits the preparation of inverse emulsion polymers (P(AM-AA-AMPS)). The obtained P(AM-AA-AMPS) polymer emulsion features remarkable stability even after 15 days of storage. Importantly, the P(AM-AA-AMPS) polymer was released from the emulsion efficiently by pH stimulation instead of introducing an extra hydrophilic surfactant, which confirmed the improvement of polymer release by pH stimulation. The viscosity of the P(AM-AA-AMPS) polymer aqueous solution reaches a maximum value of 96 mPa s within 80 s at a pH value of 9.2. The release efficiency of P(AA-AM-AMPS) polymer emulsion is increased by 33% in comparison with that of traditional polymer emulsion (2 min). The P(AM-AA-AMPS) emulsion demonstrated remarkable drag-reduction performance by achieving a drag-reduction rate of 73% at a concentration of 0.05 wt %. P(AM-AA-AMPS) polymer emulsion with pH responsiveness eliminates the contradiction between the stability and release of emulsion drag reducers. Research based on pH-responsive P(AM-AA-AMPS) polymer emulsion provides other ideas for the development of quickly dissolving and long-term storage drag reducers, which is helpful for the development of low-permeability oil and gas resources.
作为滑溜水压裂液的关键组分，乳液减阻剂起着至关重要的作用。通过添加亲水性表面活性剂提高了传统乳液减阻剂的溶解能力，这导致乳液减阻剂的稳定性较差。为了消除乳液减阻剂稳定性与释放之间的矛盾，在此，使用开关溶剂（HA）和白油作为连续相制备了pH响应型聚合物乳液。单体乳液表现出明显的pH响应行为。这是因为pH刺激使HA去质子化，导致乳液油水比发生变化，从而促进乳液破乳。单体乳液的显著稳定性有利于反相乳液聚合物（P(AM-AA-AMPS)）的制备。所获得的P(AM-AA-AMPS)聚合物乳液即使在储存15天后仍具有显著的稳定性。重要的是，通过pH刺激而不是引入额外的亲水性表面活性剂，P(AM-AA-AMPS)聚合物能有效地从乳液中释放出来，这证实了pH刺激提高了聚合物的释放率。在pH值为9.2时，P(AM-AA-AMPS)聚合物水溶液的粘度在80 s内达到最大值96 mPa·s。与传统聚合物乳液（2分钟）相比，P(AA-AM-AMPS)聚合物乳液的释放效率提高了33%。P(AM-AA-AMPS)乳液在浓度为0.05 wt%时实现了73%的减阻率，表现出显著的减阻性能。具有pH响应性的P(AM-AA-AMPS)聚合物乳液消除了乳液减阻剂稳定性与释放之间的矛盾。基于pH响应型P(AM-AA-AMPS)聚合物乳液的研究为快速溶解和长期储存减阻剂的开发提供了其他思路，这有助于低渗透油气资源的开发。
