Delving into the Jurassic sediments of the Matruh basin, Northwestern Desert, Egypt: A multidisciplinary approach using seismic data, stratigraphic analysis, and 3D facies modeling

Abstract

This study integrates multiscale datasets, including seismic interpretation, well-log analysis, and sequence stratigraphy, to evaluate reservoir potential and spatial distribution within the Khatatba Formation of the Obayied Oilfields, Northwestern Desert, Egypt. Seismic interpretation reveals NE-SW trending horsts, grabens, and step faults, segmenting the study area into eleven structural blocks. Structural cross-sections highlight lateral extensions, thickness variations, and fault-controlled reservoir compartmentalization. The Khatatba Formation is analyzed within the Masajid-Khatatba sequence (M.K. SQ), exhibiting mixed siliciclastic and carbonate lithofacies, distinct wireline-log signatures, and seismic reflections. Petrophysical analysis identifies the sandstone-rich LST-1 as a key reservoir zone, while the Masajid Formation offers limited potential. Advanced 3D facies models of the Upper and Lower Safa Members enhance insights into structuration and facies distribution. The Upper Safa Member exhibits porosity of 10–18 %, shale volume of 15–24 %, and water saturation of 18–53 %, while the Lower Safa Member shows porosity of 10–16 %, shale volume of 17–28 %, and water saturation of 15–47 %, with improved reservoir quality in the northeast and southeast, respectively. Geochemical analysis indicates Total Organic Carbon (TOC) values of 1–5 % in Jurassic formations, confirming moderate to good source rock potential. The Upper Jurassic Masajid Formation, with substantial carbonate content, serves as an effective seal rock, while faults from Late Cretaceous to Early Miocene inversion structures influence hydrocarbon migration and reservoir compartmentalization. These findings enhance understanding of hydrocarbon prospectivity, providing a foundation for optimized exploration and development strategies in the Obayied Field and the broader Matruh-Shushan Basin.