Driving Recovery Efficiency in Offshore Fields Through Completion Excellence

Abstract A large offshore UAE carbonate reservoir presents significant challenges due to advanced maturity, a substantial gas cap, and pronounced heterogeneity, which have led to uneven production profiles and early gas breakthrough. More than 30% of oil producers are shut because of high gas-oil ratios (GOR), and this percentage continues to rise, threatening the feasibility of future development. ADNOC Offshore initiated a pilot program to evaluate viscosity-based Autonomous Inflow Control Valve (AICVs) as a solution to mitigate gas production while sustaining oil output under high export pressure conditions. These devices dynamically adjust flow based on fluid viscosity, offering an advantage over conventional passive inflow control devices that cannot respond after breakthrough. Two inactive horizontal wells were selected for retrofit installation following a detailed screening process, and a newly drilled well was completed across two reservoir bodies with distinct petrophysical properties. Prior to installation, comprehensive nodal analysis and reservoir simulation studies were conducted to assess device performance under multiphase flow and high-pressure constraints. Baseline Production Logging Tool (PLT) surveys confirmed that gas production was concentrated near the heel sections of the wells. Post-installation results demonstrated delayed gas breakthrough, improved inflow uniformity, and extended well life. Time-lapse PLTs and bottomhole pressure monitoring validated successful gas choking and adaptive flow control, although one pilot recently exhibited rising GOR due to gas encroachment, indicating the gas front has moved closer to the wellbore. The newly drilled well initially produced dry oil with no free gas, confirming effective zonal isolation and device functionality. Over the first year, production remained stable with minimal gas output, and PLT data indicated most oil contribution came from the high-permeability reservoir body. As gas eventually reaches this zone, the AICV will automatically restrict gas inflow, allowing the low-permeability zone to contribute more significantly, optimizing recovery and delaying high GOR. Another PLT survey is planned when gas production increases to validate device performance and inform future optimization. Lessons learned emphasize the importance of integrated subsurface evaluation, completion design optimization, and continuous monitoring. Flow loop experiments using ADNOC fluids are scheduled to calibrate device models and enhance predictive accuracy. Building on these results, autonomous devices for water control and injection profile modification are planned for upcoming projects to mitigate unwanted water production and improve sweep efficiency. These advancements position AICVs as a critical enabler for sustainable field development, offering practical solutions to complex reservoir challenges and enabling incremental reserves recovery in high-GOR environments.