Integrated 3D static modelling to assess hydrocarbon potential of the fluvial-alluvial sandstones of Nukhul Formation, October oil field, Gulf of Suez, Egypt

One of the biggest hydrocarbon accumulations in the Gulf of Suez, the huge October Oil Field, has a structurally complex syn-rift sequence with poorly limited reservoir distribution and quality. One of the most important target reservoirs is the Nukhul Formation. However, the field development is challenged by facies architecture, porosity, shale distribution, and fault geometries that complicate replication of the Nukhul reservoir’s reported heterogeneity. These difficulties are crucial for enhancing and improving field development, particularly from the Nukhul reservoir, which was depleted and had a very low oil rate. It was thought that this type of reservoir had disappeared, leaving little opportunity for development. This study aims to manage and increase oil production from the Nukhul reservoir by updating structural interpretation, which reveals revised fault geometry and compartment configurations, providing better restrictions on trap integrity and reservoir continuity. Historical datasets collected by multiple operators (1980–2020), combined with recently reprocessed seismic interpretations, were integrated to reconstruct stratigraphic geometries more accurately than previously achievable. It was crucial to update and modify the structural model to preserve favourable reservoir quality and extension across different locations, forming the basis for improved facies and static modelling. The Nukhul Formation was divided into four zones (K1–K4) based on detailed correlation integrated with petrological descriptions and dynamic data. This division highlights the dominance of low-porosity limestone–shale units in K1–K2, discontinuous fluvial sandstone bodies in K3, and thick, laterally linked channelized sandstones in K4. Model results identify undrilled reservoir extensions, attic accumulations, and high-quality sandstone corridors. These results provide actionable targets for near-field exploration and infill drilling, significantly reducing uncertainty in reservoir extent and quality, improving dynamic behaviour prediction, and supporting volumetric calculations, flow-unit delineation, and uncertainty quantification. The findings demonstrate that the Nukhul reservoir still retains production potential and can contribute to field redevelopment. The approach used here offers a stable and portable framework for characterizing heterogeneous syn-rift reservoirs in structurally dynamic basin-margin environments and promotes optimal field redevelopment plans.