Integrated source-rock evaluation, oil-source correlation, and one-dimensional basin modeling, Meleiha concession, Northwestern Western Desert, Egypt

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This study presents an integrated geochemical evaluation and basin modeling of the Arcadia-1X well in the Meleiha Concession, Northwestern Western Desert, Egypt, to characterize the Jurassic-Cretaceous petroleum system. The Jurassic source rocks exhibit significant lithological heterogeneity, with coal and carbonaceous shale intervals showing excellent gas generation potential (TOC up to 75.2 wt%), while organic-rich shales show fair to good organic richness (TOC 0.54–6.46 wt%, median 1.93 wt%). Kerogen characterization reveals predominantly Type III organic matter with minor Type II/III mixtures, indicating gas-prone source potential with limited oil generation capacity. Thermal maturity assessment based on Tmax (447 °C–474 °C) and vitrinite reflectance (0.79%–1.5% Ro for Jurassic intervals) indicates that the Lower Cretaceous Alam El Bueib source rocks are in the early oil window, while the Jurassic source rocks have reached peak to late oil window maturity. Biomarker and stable carbon isotope analyses demonstrate a strong genetic relationship between the Alam El Bueib oil and Jurassic source rock extracts, confirming generation from deeper Jurassic sequences with vertical migration into the overlying Cretaceous reservoir. Basin modeling reveals that the Jurassic source rocks entered the oil window during the Late Cretaceous (ca. 85–90 Ma), with peak oil generation during the mid-Eocene to Oligocene (ca. 35–40 Ma), and continuous gas generation from the Paleogene to the present. The integrated results demonstrate that the Meleiha Concession petroleum system is primarily gas-prone, with the Lower Safa Formation serving as the principal source rock. These findings have significant implications for exploration in the Shushan Basin, particularly for deeper Jurassic targets where favorable structural and stratigraphic conditions coincide with mature source rocks.