Optimization of CO 2 Injection for EOR and Storage in Low-Permeability Reservoirs

作者：Qiaozhen Chen, Zhichao Zhang, Yu Liu, Mingxing Bai, Chao Liu, Huili Zhang · 发表于：Energy & Fuels · 年份：2026 · DOI：10.1021/acs.energyfuels.6c00831 · 被引用次数：2 · 研究领域：Enhanced Oil Recovery Techniques、CO2 Sequestration and Geologic Interactions、Reservoir Engineering and Simulation Methods

Based on the issue of low efficiency of CO 2 displacement and sequestration in different low-permeability reservoirs, the impact of different CO 2 injection methods (continuous CO 2 injection, water-alternating-gas (WAG), and Huff and Puff (HnP)) on the microscopic oil production and CO 2 storage in low-permeable reservoirs are studied by conducting several experiments, aiming to select the optimal CO 2 injection and storage strategy. Nuclear magnetic resonance (NMR) was employed to analyze the microscopic oil recovery and CO 2 storage within different scales of pores of cores. The results indicate that CO 2 miscible injection enhances mass transfer and reduces interfacial tension (IFT) between CO 2 and crude oil, expands the CO 2 sweep volume and oil washing efficiency in reservoir cores, and ultimately improves the oil recovery. CO 2 miscible WAG (CO 2 -M-WAG) with a gas–water ratio of 1:1 and a single water or CO 2 slug size of 0.1 pore volume (PV) of cores achieved the highest oil recovery and CO 2 storage percentage after displacing the cores, followed by continuous CO 2 miscible flooding (CO 2 -MF). In contrast, the use of a CO 2 miscible Huff and Puff (CO 2 -M-HnP) resulted in relatively low oil recovery and CO 2 storage for the cores. During the process of CO 2 -M-WAG, the mass transfer between CO 2 and the oil phase is promoted, and the premature breakthrough at the core outlet end is also mitigated by stabilizing the CO 2 displacement front. Otherwise, relative perm...