Abstract
The Sirte Shale is one of the most significant source rock intervals in the Sirt Basin, Libya, and has played a fundamental role in the generation and accumulation of hydrocarbons throughout the basin. Understanding its petroleum generation history is essential for reconstructing the evolution of the regional petroleum system, identifying active hydrocarbon kitchens, and reducing exploration risk. This study investigates the petroleum generation history of the Sirte Shale by integrating regional geological interpretation, organic geochemical data, thermal maturity analysis, and basin modeling. Source rock characterization was performed using Total Organic Carbon (TOC), Rock-Eval pyrolysis, Hydrogen Index (HI), Tmax, vitrinite reflectance (Ro), kerogen typing, and biomarker analyses to evaluate organic richness, kerogen quality, and thermal maturity. These data were incorporated into calibrated basin models to reconstruct burial history, thermal evolution, hydrocarbon generation, and petroleum expulsion through geological time. The results indicate that the Sirte Shale contains predominantly oil-prone Type II kerogen with good to excellent organic richness, deposited under marine anoxic conditions favorable for organic matter preservation. Petroleum generation commenced during progressive burial in the Late Cretaceous and intensified throughout the Paleocene time as subsidence increased thermal maturity. Peak oil generation occurred within the deep basin depocenters, whereas structurally elevated regions remained immature to marginally mature. The timing of hydrocarbon generation closely corresponds with the formation of migration pathways and traps, facilitating efficient petroleum charge into major reservoirs across the basin. The integrated geochemical and basin modeling approach provides a comprehensive understanding of the petroleum generation history of the Sirte Shale and highlights the key controls of burial history, heat-flow evolution, and source rock characteristics on hydrocarbon generation. These findings improve petroleum system evaluation and provide valuable guidance for future hydrocarbon exploration and resource assessment in the Sirt Basin.