Study on Production Characteristics during N2 Flooding in Low Permeability Reservoirs: Effect of Matrix Permeability and Fracture

The N2 flooding enhanced oil recovery process is an important technical means for the development of low permeability reservoirs due to its good energy enhancement effect and injectivity. Low have a large span strong heterogeneity, which will significant impact on gas injection development. In order explore influence matrix fractures production characteristics flooding, this study conducted series displacement experiments with full-scale (0.1–50 mD) different fracture conditions. research results indicate that, in non-fracture cores, pressure difference decreased increase, volume required achieve highest decreased. addition, increase accelerates breakthrough channeling, but beneficial improving no-gas ultimate decrease crude flow resistance. ranges varies. When less than 2 mD, are significantly affected by changes permeability. greater effectiveness weakened. existence causes high channel appear matrix, exacerbating reducing utilization (about 50% recovery). weakening heterogeneity between alleviating thereby increasing swept recovery.