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

Carbon dioxide (CO₂) 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 CO₂ 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 CO₂ 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 CO₂ 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 CO₂ recovery rate reaches 2%, the lower limit of oil saturation is 0.57. When the oil saturation is 0.5 and the CO₂ 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 CO₂ 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 CO₂ throughput test plans. [ABSTRACT FROM AUTHOR]