Influence of fracture on CO₂ huff-n-puff efficiency and pore-scale shale oil mobilization in shale reservoirs

Abstract CO 2 huff and puff (HnP) is widely recognized as an effective strategy for enhancing shale oil recovery. However, a comprehensive understanding of its multi-scale performance in fractured shale reservoirs remains limited. To bridge this gap, this study investigates the enhanced oil recovery (EOR) potential of CO 2 HnP, with a particular focus on the influence of fractures. A series of large-diameter core HnP experiments, combined with online nuclear magnetic resonance (NMR) analysis, we