Uncertainty Analysis of Hydrocarbon Estimation Using 3D Geological Model: A Case Study of the F3 Sandstone Reservoir, Ghadames Basin, Libya

The Wafa oil and gas field, located in Libya's Ghadames Basin, has historically faced challenges in accurately characterizing its F3 Sandstone Reservoir due to limited structural and stratigraphic data, particularly in certain wells. This study addresses these gaps by employing a comprehensive 3D geological model to evaluate the reservoir's structural and petrophysical properties across five newly drilled wells. Utilizing Petrel software, geological and petrophysical models were developed, with porosity and water saturation values derived from well log data processed in Techlog software. Results reveal significant heterogeneity in reservoir properties, with porosity levels ranging from 12% to 17% in most wells, while well A12 exhibits negligible porosity due to lithological variations. Water saturation levels range from 30% to 45% in the northwest, increasing to 100% in the southern well A12. The structural model highlights the potential for oil trapping in the F3 reservoir, with distinct facies and petrophysical variations observed across the study area. Rock typing analysis further underscores the heterogeneity within the F3 members, with the northern region demonstrating favorable petrophysical characteristics and porosity, contrasting with the less promising southern region. This study provides critical insights into the geological and petrophysical properties of the F3 Sandstone Reservoir, offering valuable guidance for hydrocarbon exploration and production in the Ghadames Basin. The integration of 3D geological modeling and petrophysical analysis underscores the need for high-resolution seismic data to enhance reservoir characterization accuracy, thereby supporting informed decision-making for future exploration and development efforts.