RESEARCH ARTICLE Petroleum geology: 3D reservoir modelling in the central Gulf of Suez, Egypt, to estimate the hydrocarbon possibility via petrophysical analysis and seismic data interpretation Esam A. Gawad 1 | Mohamed Fathy 1 | Mohamed Reda 1 | Hatem Ewida 2 1 Geology Department, Faculty of Science, Al-Azhar University, Cairo, Egypt 2 PERENCO - North Sinai Petroleum Company, Cairo, Egypt Correspondence Mohamed Reda, Geology Department, Faculty of Science, Al-Azhar University, P.O. Box 11884, Nasr City, Cairo, Egypt. Email: mohamedreda.88@azhar.edu.eg Handling Editor: R. Flood October oil field is considered one of the most prolific areas in the central Gulf of Suez, which recently suffered a lack of production in some areas, in addition to some wells that have begun to deplete, which negatively affects the economic value of this field. 3D integrated reservoir model on five wells has been performed to simulate the subsurface structural setting, petrophysical modelling, and distribu- tion of facies modelling of the Late Cretaceous Matulla Formation and Early Miocene Asl Member of Upper Rudeis Formation, which are the main oil-bearing reservoirs in this study. Structural modelling controlled by the incorporation of explained structures, horizons, and picked zones for 3D grid express northwest– southeast to northeast–southwest fault systems, whilst facies modelling has enabled the spatial distribution of lithologic facies within the established 3D struc- tural model reflecting two types of facies: marine carbonates and lagoon shale, and the petrophysical modelling explained a complete distribution of the petrophysical characteristic of the Matulla and Asl oil reservoirs revealed good reservoir charac- teristics, which are high net pay, high effective porosity, low shale content, low water saturation, and high hydrocarbon saturation. Therefore, three new commer- cial promising areas were identified to raise the productive value of this field according to the three-way dip closure, petrophysical results, and the facies distribution. KEYWORDS 3D reservoir modelling, October oil field, property modelling, prospect estimation, structural modelling 1 | INTRODUCTION October oil field is located in the middle part of the Gulf of Suez of Egypt, between latitudes 28  45 0 and 28  55 0 N and longitudes 33  00 0 and 33  10 0 E; this region may be a portion of the Gulf of Suez basin, which is believed to be the foremost productive petroleum area in Egypt (Figure 1). The development of carbonate reservoirs is challenged with the complexity of carbonate heterogeneities of petrophysical and lithological properties, which are the outcome of a history of variable diagenetic and depositional conditions (Raef, Totten, Linares, & Kamari, 2019; Eberli 1999). It is critically important to calculate and calibrate the petrophysical results and facies distribu- tion during the construction of the reservoir modelling. The struc- tural, facies, and petrophysical modelling are noteworthy within the petroleum exploration to progress hydrocarbon-reserve assess- ment, empowering well-informed field advancement, putting infill wells, and predicting reservoir production (Abdel-Fattah, 2010; Abdel-Fattah, Metwalli, & Mesilhi, 2018). The conducted 3D Received: 21 April 2021 Accepted: 6 August 2021 DOI: 10.1002/gj.4241 Geological Journal. 2021;1–14. wileyonlinelibrary.com/journal/gj © 2021 John Wiley & Sons Ltd. 1