This study provides a comprehensive review of the petroleum systems in the Iranian Zagros and Persian Gulf regions, spanning the Phanerozoic, with the objective of synthesizing geological, geochemical, and basin modeling data to enhance exploration strategies. Three primary petroleum systems are identified: Paleozoic-Triassic, Jurassic-Cretaceous, and Cenozoic, each characterised by distinct source rocks, reservoirs, and seals. The methodology integrates extensive literature reviews and original geochemical analyses, including Rock-Eval pyrolysis, vitrinite reflectance, biomarker studies, carbon isotope and kinetic modeling, to assess source rock maturity, kerogen type, and oil-source correlations. Main results highlight the Paleozoic-Triassic system, driven by Silurian Sarchahan "hot shales," feeding gas-rich Permian-Triassic Dalan and Kangan reservoirs, sealed by Triassic Dashtak evaporites, though challenged by deep burial and high non-hydrocarbon content. The Jurassic-Cretaceous system, contributing over 50% of Iran's oil, features oil-prone Sargelu, Garau, and Kazhdumi source rocks, with reservoirs in the Khami and Bangestan groups, sealed by Hith/Gotnia and Gurpi formations. The Cenozoic system, centered in the Dezful Embayment, relies on the Pabdeh source rock, Asmari reservoir, and Gachsaran seal, with significant vertical migration from underlying Mesozoic systems. Chemometric classification of 21 oil samples reveals three distinct oil families linked genetically to these petroleum systems. Family A oils are attributed to Upper Jurassic to Miocene source rocks, characterised by a high C28/C29 regular sterane ratio. Family B oils correlates to Jurassic or older source rocks, classified as high-maturity ones. Family C oils sourced from the Aptian-Albian Kazhdumi Formation displaying biomarker parameters indicative of anoxic marine conditions.
Hassanzadeh et al. (Wed,) studied this question.