Liu Tianqi, Zhang Yan, Feng Yujun
Polymer Research Institute, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, People's Republic of China.
ACS Omega. 2025 Jun 3;10(23):24181-24193. doi: 10.1021/acsomega.4c10944. eCollection 2025 Jun 17.
Gas channeling during the CO flooding process significantly reduces both oil recovery and the level of CO storage. Polymer microspheres have emerged as gas channeling control agents due to their superior strength and injectability. However, the rapid and uncontrolled swelling of most reported polymer microspheres impedes their in-depth transportation and effective plugging in porous media under high-temperature and high-salinity environments. To address these challenges, a series of CO-triggered and delayed swelling polymer microspheres (denoted as DVP), incorporating dimethylaminopropyl methacrylamide (DMAPMAm), -vinyl-2-pyrrolidone (NVP), and ,'-methylenebis-(acrylamide) (MBA) as the CO-responsive monomer, salt- and temperature-resistant component, and cross-linker, respectively, were prepared using inverse microemulsion polymerization. The impacts of monomer composition and cross-linker content on the morphology and swelling behavior of DVP in aqueous solutions were investigated, and the gas channeling control capacity of DVP was evaluated in an artificial core. The results showed that the CO-induced swelling ratio of DVP augments with higher contents of DMAPMAm and cross-linker yet decreases when the dosage of cross-linker exceeds 0.5%. After aging for 8 days at 140 °C and in 15,000 mg/L brine, the particle size of DVP, having a DMAPMAm dosage of 50% and an MBA content of 1%, gradually expands from 280 to 701 nm with a swelling ratio of 2.50. In this case, using this DVP aged in situ for 8 days within a fractured core with an original permeability of 10 mD leads to a plugging efficiency as high as 99%. This work provides a new idea for the development of materials for the control of CO gas channeling.
CO驱油过程中的气窜会显著降低原油采收率和CO封存水平。聚合物微球因其优异的强度和可注入性，已成为气窜控制剂。然而，大多数报道的聚合物微球快速且不受控制的溶胀阻碍了它们在高温高盐环境下在多孔介质中的深度运移和有效封堵。为应对这些挑战，采用反相微乳液聚合法制备了一系列CO触发和延迟溶胀的聚合物微球（记为DVP），分别引入甲基丙烯酰二甲胺丙酯（DMAPMAm）、N-乙烯基-2-吡咯烷酮（NVP）和N,N'-亚甲基双丙烯酰胺（MBA）作为CO响应单体组分、抗盐抗温组分和交联剂。研究了单体组成和交联剂含量对DVP在水溶液中的形态和溶胀行为的影响，并在人造岩心中评价了DVP的气窜控制能力。结果表明，DVP的CO诱导溶胀率随DMAPMAm和交联剂含量的增加而增大，但当交联剂用量超过0.5%时溶胀率降低。在140℃和15000mg/L盐水中老化8天后，DMAPMAm用量为50%、MBA含量为1%的DVP粒径从280nm逐渐增大到701nm，溶胀率为2.50。在这种情况下，将这种原位老化8天的DVP用于初始渗透率为10mD的裂缝岩心中，封堵效率高达99%。这项工作为开发CO气窜控制材料提供了新思路。
