Re-Evaluating Oil Potential in Residual Oil Zone Through Integration of Static and Dynamic Data in a Giant Carbonate Brown Field, Offshore Abu Dhabi

Abstract Recent studies have demonstrated that residual oil zones (ROZ) below the free water level (FWL) in carbonate reservoirs can contain significant volumes of oil that are not recoverable by conventional methods but may be mobilized through enhanced oil recovery (EOR) techniques such as CO2 or water injection. However, most previous work has treated the ROZ as a single, undifferentiated interval, without detailed characterization of sub-category or direct integration of dynamic data. In this study, we present an integrated workflow for evaluating the oil potential within the ROZ of a giant offshore carbonate field in Abu Dhabi, utilizing a combination of Movable Hydrocarbon Index (MHI), water saturation (Sw) logs, fluid identification (FID), wettability measurements, and pressure data. By correlating these datasets, we subdivide the ROZ with wetting phase and clarify the depth distribution of each. Our results reveal that significant intervals containing potentially movable oil exist below the current FWL, with their distribution closely linked to wettability transitions and pressure inflections. This approach enables more accurate net pay estimation and provides a practical basis for optimizing EOR strategies in heterogeneous carbonate reservoirs. The findings highlight the importance of integrating static and dynamic data for detailed ROZ characterization, moving beyond the limitations of previous studies.