Xu Chao, Pei Enhui, Li Hongbo, Wang Chunsheng
Key Laboratory of Enhanced Oil and Gas Recovery of Ministry of Education, Northeast Petroleum University, Daqing 163000, China.
ACS Omega. 2025 Aug 22;10(35):39850-39860. doi: 10.1021/acsomega.5c04022. eCollection 2025 Sep 9.
CCUS technologies for enhanced oil and gas recovery rely on the unique properties of CO to enable efficient displacement and secure geological storage, presenting a cost-effective and practical approach to mitigate greenhouse gas emissions and support global carbon neutrality objectives. This study systematically evaluates the development effects of different CO flooding methods in low-permeability reservoirs through 1 m artificial long-core physical simulation experiments and reveals the synergistic enhancement mechanisms of foam-CO alternating flooding. The core model is constructed by the harmonic permeability sorting method (permeability 2.6-3.9 mD, porosity 6.35-11.13%), and the displacement characteristics of four schemes are compared and analyzed, including continuous CO gas flooding, water-gas alternating flooding, foam-assisted continuous flooding, and foam-CO alternating flooding. The results show that the foam-CO alternating flooding (0.15 PV slug) performs optimally, with a recovery efficiency of 60.75%, which is 23.69 and 7.49% higher than that of continuous gas flooding and water-gas alternating flooding, respectively, and the gas channeling breakthrough time is delayed to 0.48 PV (29.7% later than traditional gas flooding). Its synergistic enhancement mechanisms include: (1) the Jamin effect of foam reduces gas mobility by 73%, forcing the fluid to divert to medium-low permeability regions; (2) the compound surfactant (0.5% AEO-9 + 0.3% CHSB) works synergistically with CO to significantly enhance the microscale oil displacement efficiency; (3) the coupling analysis of pressure response and production dynamics confirms a three-level synergistic mechanism of "mobility control-interfacial regulation-sweep volume expansion". Furthermore, the core construction method based on harmonic permeability effectively reduces the interference of heterogeneity on experimental results, providing an experimental basis for the optimization of CO flooding injection parameters in low-permeability reservoirs and the adaptability evaluation of CCUS technologies. The research results provide theoretical support and technical paths for the dual goals of efficient development of low-permeability reservoirs and carbon emission reduction.
用于提高油气采收率的碳捕集、利用与封存（CCUS）技术依赖于二氧化碳（CO₂）的独特性质来实现高效驱替和安全地质封存，为减少温室气体排放和支持全球碳中和目标提供了一种经济高效且切实可行的方法。本研究通过1米长的人工岩心物理模拟实验，系统评估了不同CO₂驱替方法在低渗透油藏中的开发效果，并揭示了泡沫-CO₂交替驱替的协同强化机制。岩心模型采用调和渗透率分级法构建（渗透率2.6 - 3.9毫达西，孔隙度6.35 - 11.13%），并对比分析了连续CO₂气相驱替、水气交替驱替、泡沫辅助连续驱替和泡沫-CO₂交替驱替四种方案的驱替特征。结果表明，泡沫-CO₂交替驱替（0.15孔隙体积段塞）效果最佳，采收率为60.75%，分别比连续气相驱替和水气交替驱替高出23.69%和7.49%，气窜突破时间延迟至0.48孔隙体积（比传统气相驱替晚29.7%）。其协同强化机制包括：（1）泡沫的贾敏效应使气体流度降低73%，迫使流体转向中低渗透区域；（2）复合表面活性剂（0.5%AEO - 9 + 0.3%CHSB）与CO₂协同作用，显著提高微观尺度的驱油效率；（3）压力响应与生产动态的耦合分析证实了“流度控制-界面调控-波及体积扩展”的三级协同机制。此外，基于调和渗透率的岩心构建方法有效降低了非均质性对实验结果的干扰，为低渗透油藏CO₂驱替注入参数优化及CCUS技术适应性评价提供了实验依据。研究结果为低渗透油藏高效开发和碳排放减少双重目标提供了理论支持和技术路径。
