Zhang Miaoxin, Wu Jingchun, Cai Liyuan, Li Bo, Yu Xin, Hou Yangyang, Fang Shi, Zhang Chunlong
Key Laboratory for EOR Technology (Ministry of Education), Northeast Petroleum University, Daqing 163318, China.
Daqing Yongzhu Petroleum Technology Development Co Ltd., Daqing 163000, China.
ACS Omega. 2025 Aug 26;10(35):40402-40415. doi: 10.1021/acsomega.5c05748. eCollection 2025 Sep 9.
Aiming at the problems of high clay mineral content in strong water-sensitive reservoirs and easy hydration expansion caused by foreign fluids, a clay inhibitor (silyl quaternary ammonium salt DSC) was prepared using 2-(dimethylamino)-ethyl methacrylate and (3-chloropropyl)-trimethoxysilane as raw materials. This is the first report on the synergistic application of silyl quaternary ammonium salt (DSC) and CO for enhanced oil recovery in strongly water-sensitive reservoirs, realizing the dual effects of clay stabilization and CO seepage enhancement. It is demonstrated that the synergy of DSC/CO increases the oil recovery rate by 47.29% compared to traditional water flooding, with a 0.35 PV delay in gas channeling. The DSC system, composed of DSC, ethylene glycol, inorganic salt, and nonionic surfactant, stabilizes pore structures through synergistic charge neutralization, hydrogen bond inhibition, and electric double-layer compression, with an antiswelling rate of 93.92% and dissolution rate of 5.32%. The study on the synergistic effect of the DSC system and CO found that the CO diffusion coefficient in DSC-saturated cores increased to 9.226 × 10 m/s (16 times higher than that in formation water-saturated cores), the initiation pressure gradient was reduced by 2 orders of magnitude compared with simulated water flooding, and the antiswelling rate decreased by only 13.72% after multiple rounds of flushing in an acidic environment. It was confirmed that DSC reconstructed the pore surface energy through silyl bonding, significantly improving the CO seepage capacity. Nuclear magnetic resonance (NMR) proved from a microscopic perspective that the synergy of DSC and CO increased the recovery rate of the remaining oil in small pores by 25.08%. Macroscopic oil displacement experiments further showed that the total recovery rate of DSC system flooding + gas-liquid alternating flooding reached 62.85%. The proposed technical model of "dual-effect stable flow-synergistic oil recovery-delayed gas channeling" provides a solution with both technical feasibility and economic rationality for the development of low-permeability water-sensitive reservoirs and CO geological storage. Future research will focus on formula optimization and adaptability studies for reservoirs with different clay compositions.
针对强水敏油藏黏土矿物含量高、外来流体易引发水化膨胀等问题，以甲基丙烯酸-2-(二甲氨基)乙酯和(3-氯丙基)三甲氧基硅烷为原料制备了一种黏土抑制剂（硅烷基季铵盐DSC）。这是首次关于硅烷基季铵盐（DSC）与CO协同应用于强水敏油藏提高采收率的报道，实现了黏土稳定和CO渗流增强的双重效果。结果表明，与传统水驱相比，DSC/CO协同作用使采收率提高了47.29%，气窜延迟了0.35PV。由DSC、乙二醇、无机盐和非离子表面活性剂组成的DSC体系通过协同电荷中和、氢键抑制和双电层压缩作用稳定孔隙结构，防膨率为93.92%，溶解率为5.32%。对DSC体系与CO协同效应的研究发现，CO在DSC饱和岩心中的扩散系数增至9.226×10 m/s（比地层水饱和岩心中高16倍），启动压力梯度比模拟水驱降低了2个数量级，在酸性环境中多次冲刷后防膨率仅降低13.72%。证实DSC通过硅烷基键合重构了孔隙表面能，显著提高了CO渗流能力。核磁共振（NMR）从微观角度证明，DSC与CO协同作用使小孔剩余油采收率提高了25.08%。宏观驱油实验进一步表明，DSC体系驱替+气液交替驱替的总采收率达到62.85%。所提出的“双效稳流-协同采油-延迟气窜”技术模式为低渗透水敏油藏开发及CO地质封存提供了技术可行且经济合理的解决方案。未来研究将聚焦于针对不同黏土组成油藏的配方优化及适应性研究。
