Organic geochemistry and petrographic characteristics of the shales from the Late Miocene Zeit Formation in the Tokar area, Red Sea Basin: Implications for depositional environment and hydrocarbon potential

Abstract According to the geochemistry, organic petrography, stable carbon isotopic compositions and biomarker analyses of the Late Miocene Zeit Formation shale samples in the Tokar area, Red Sea Basin, the paleoenvironment and hydrocarbon-generating potential were analyzed. The Zeit Formation shales from the Wells S. Suakin-1 and Tokar-1 contain mostly Type III kerogens with minor Type II organic matter (OM), indicating more favorable gas-generating potential. OM of the shale samples from the Late Miocene Zeit Formation are predominantly of terrigenous higher plants. Kerogens from the Well Tokar-1 show abundant brown liptinites, indicating the mixed origin of planktonic/bacterial and terrigenous OM. The Late Miocene Zeit Formation was deposited in dysoxic/suboxic, reducing and salt water environments. According to the results of Tmax, Ro and biomarker maturity parameters, the most shale samples from the Zeit Formation are in early mature to mature stages. The shales from the Late Miocene Zeit Formation are generally fair to good source rock. The shales from wells Suakin-2, Talla-2 and Tokar-1 have high hydrocarbon-generating potential.