Enhancing CO2 Huff N Puff Strategies for Improved Oil Recovery in the Bakken Formation: A Numerical Simulation Approach

This study investigates the performance of various Huff and Puff (HnP) strategies for enhanced oil recovery (EOR) in the Sanish field of the Bakken formation, using a numerical model developed with CMG software. The model integrates PVT validation, CO 2 miscibility, swelling tests, heterogeneity, and history matching with field data. Several HnP strategies, including Supported (S HnP), Alternative Supported (AS HnP), and Alternative Zigzag Supported (AZS HnP), were evaluated. Key findings show that dual porosity and permeability are essential for accurate modelling, while CO 2 diffusion has minimal impact in field-scale simulations with high fracture spacing. The S HnP strategy improves oil recovery with 50% less CO 2 than the Normal HnP, and the AS HnP further enhances production. The AZS HnP outperforms both, offering higher oil recovery and better CO 2 utilization. Fracture length was found to influence recovery significantly, and the sensitivity of oil production to CO 2 injection rates was notably higher in the AZS HnP compared to the N HnP scenario. These results highlight the potential for optimized CO 2 -EOR strategies in unconventional reservoirs. • Advanced CO 2 Huff N Puff strategies (S HnP, AS HnP, AZS HnP) enhanced oil recovery in tight reservoirs. • Validated a robust numerical model using Bakken field data, incorporating heterogeneity and dual porosity. • AZS HnP achieved higher oil recovery with 50% less CO 2 compared to traditional methods. • Hydraulic fracture length and CO 2 injection rate significantly impacted recovery efficiency. • Field-scale modeling confirmed negligible CO 2 diffusion in naturally fractured formations.