Abstract
This study presents an integrated 3D structural modelling workflow as a quantitative framework for applying advanced geological understanding to the spatial distribution of discrete and continuous reservoir properties of the underexplored, structurally complex Nukhul Formation in the October Oil Field. The updated 3D structural model was constructed by integrating high-resolution seismic interpretation with multidisciplinary subsurface datasets, including electric logs, detailed stratigraphic correlations, petrophysical evaluation, and production performance data from drilled wells. The current study specifically evaluates the structural controls on reservoir distribution and trapping styles within the field by combining 3D seismic interpretation with well-log and core-derived information. The refined model reveals a fault architecture dominated by a NNW–SSE (Clysmic) trend, with major faults dipping south-southwest (SSW) and horizons oriented northeast (NE), as determined from dipmeter data and seismic interpretation. The Nukhul reservoir is defined by a three-way dip closure, bounded by fault-dependent seals, where sealing capacity is governed by fault throw that juxtaposes permeable sand layers against impermeable lithologies. This configuration effectively inhibits cross-fault hydrocarbon migration, preserving attic accumulations. By integrating geological, geophysical, and petrophysical datasets, the new model significantly improves the delineation of attic targets, fault-bounded compartments, and reservoir–seal juxtapositions. Consequently, it provides refined well-placement recommendations, including high-potential attic infill drilling locations. Furthermore, the model establishes a technically robust basis for reservoir management and depletion planning, aiming to maximize recovery while minimizing water-handling risks. These outcomes demonstrate the value of incorporating new seismic and well datasets into legacy models and highlight their potential for reducing uncertainty in structurally complex syn-rift settings. Beyond the October Field, the updated structural modelling approach has broader implications for syn-rift petroleum systems in the Gulf of Suez and analogous rift basins, offering a predictive tool for fault-seal analysis, volumetric assessment, reservoir performance evaluation, and optimized drilling strategies.