Implementation and Adaptability Analysis of Numerical Simulation for Shale Oil CO 2 Huff and Puff

Carbon dioxide (CO 2 ) is being considered for use to enhance oil recovery and resource utilization and storage, with wide technical adaptability. In this paper, a numerical simulation method is used to study the adaptability of CO 2 huff and puff in shale reservoirs. A fluid model introduces the nanoconfinement effect and reflects the nanoconfinement effect using the fluid p – T phase diagram. This method uses local grid refinement and changes the permeability near the grid to characterize the reservoir reconstruction volume (SRV) fracture network while considering the CO 2 diffusion effect. The results indicate that by using the incremental recovery rate and oil change rate as references, adaptive charts can be obtained for different K f / K m and oil saturation. When K f / K m is 1000 and the increase in the CO 2 recovery rate reaches 1.5%, the lower limit of oil saturation is 0.54. When K f / K m is 1000 and the increase in the CO 2 recovery rate reaches 2%, the lower limit of oil saturation is 0.57. When the oil saturation is 0.5 and the CO 2 huff and puff oil change rate reaches 0.3, the lower limit of K f / K m is 700. Finally, when the oil saturation is 0.548 and the CO 2 huff and puff oil change rate reaches 0.6, the lower limit of K f / K m is 10. The research results are significant and can guide the design and application of on-site CO 2 throughput test plans.