Immiscible Gas Injection for Gravity Drainage in a Fractured Basement Reservoir: Case Study

Fractured basement reservoirs are notoriously difficult to develop due to their strong heterogeneity and complex oil-water interactions. In this study, immiscible gas injection for gravity drainage is considered an effective technique to enhance oil recovery in such reservoirs. Using geological and reservoir data from the study area, we investigated immiscible gas injection for gravity drainage in fractured basement reservoirs to optimize development and assess its field performance. A pilot nitrogen injection was implemented, and the results indicate that the gas injection development achieved the expected positive effects. Through the immiscible gas injection, two production wells within the pilot area showed a significant rise in their dynamic fluid levels, and reservoir pressure was also effectively restored. The success of the pilot test validated the feasibility and effectiveness of the immiscible gas injection for gravity drainage technology in the target fractured basement reservoir. It indicated the applicability of this technology mode in similar reservoirs, offering a key practical foundation and technical support for subsequent large-scale implementation and development plan optimization.