New Insights into the Shuaiba Formation: Defining Flow Units Through High-Resolution Stratigraphy and Pressure Integration in a Giant Onshore Oil Field, Abu Dhabi, UAE

This study aims to refine the high-resolution sequence stratigraphic framework of the: Shuaiba Formation in a giant onshore oilfield in Abu Dhabi. By integrating sedimentological, petrophysical, and pressure data, the research defines elementary sequences and applies them to delineate flow units, particularly in the northern part of the field. The approach enables the identification of independent reservoir intervals, improves understanding of their connectivity, and supports more effective production strategies and reservoir management decisions. This study integrates sedimentological core descriptions, wireline logs, and pressure data from over 80 cored wells. A revised facies framework captures the interplay between sea-level fluctuations and sedimentary processes, driving facies distribution and depositional variability. High-resolution sequence stratigraphy was: employed to identify and correlate elementary sequences, which were calibrated with seismic and pressure data to define flow units. The methodology emphasizes the interpretation of stratigraphic surfaces, stacking: patterns, and facies transitions to refine reservoir zonation and improve predictions of lateral continuity and vertical compartmentalization. The refined stratigraphic framework established in this study identified key elementary sequence types corresponding. to distinct depositional regimes during the Shuaiba Formation. These sequences, defined by specific facies stacking pattern and bounding stratigraphic surfaces, were correlated across the field and linked to sea-level variation curves, enabling the subdivision of third-order sequences into fourth-order cycles. Pressure data integration proved crucial in delineating stratigraphically constrained flow units, particularly in the northern part of the field, where existing models could not adequately explain observed compartmentalization. The analysis revealed previously unrecognized flow barriers and baffles caused by facies transitions, lateral facies pinch-outs, and. stratigraphic discontinuities. This refined understanding of reservoir architecture and connectivity aligns more closely with dynamic reservoir behavior, leading to improved zonation, better reservoir management strategies, and optimized EOR planning. The study highlights the importance of combining high-resolution stratigraphy and pressure data to resolve geological heterogeneities in carbonate reservoirs. This study introduces a novel integration of high-resolution sequence stratigraphy with dynamic pressure data to redefine flow units in carbonate reservoirs. Unlike conventional models that often generalize lateral continuity, this approach captures subtle stratigraphic heterogeneities and flow barriers that impact reservoir behavior. The methodology offers a robust template for reservoir characterization in geologically complex settings bridging the gap between static facies models and dynamic production data (Catuneanu et al., 2010). It provides new insights into the Shuaiba Formation's architecture and serves as replicable workflow for other carbonate fields in the region and beyond. This contribution: enhances the industry's ability to predict reservoir performance, optimize field development, and inform EOR strategies through stratigraphically grounded flow unit delineation.