The Devonian to lower-middle Permian siliciclastic strata (Zakeen and Faraghan formations) of the South Pars supergiant gas field (Persian Gulf offshore) were geochemically examined to evaluate their petroleum potential. The study was conducted on the deepest appraisal well in the Iranian sector of the Persian Gulf, using an integrated approach combining Rock-Eval pyrolysis and optical kerogen analyses (Vitrinite Reflectance-VR, Spore Color Index-SCI, Palynomorph Darkness Index-PDI, and palynofacies analyses), along with one-dimensional burial history reconstruction and thermal modeling. Generally, the low Total Organic Carbon (TOC) content in most parts of the studied formations categorizes them as poor source rocks. However, the geochemical results identified a new source rock interval, Zone-A, with high hydrocarbon generation potential. This interval is introduced as a new gas-prone prospective horizon within the Persian Gulf, deposited through a deltaic to relatively marine suboxic-anoxic environment. Our findings suggest that Zone-A has been producing hydrocarbons since the late Eocene, indicating additional undiscovered reserves in the region. This research highlights the significance of further exploration and resource assessment in the area.
