Oil seeps affinity and basin modeling used for hydrocarbon discoveries in the Kifle, Merjan, and Ekheither fields, West Iraq

摘要

Calculated C28/C29 sterane ratio, delta C13 aEuro degrees isotopes and plots of tricyclic terpane (C22/C21, C24/C23, and C26/C25 and hopane (C35S/C34S, C29/C30, and C31R/C30) of Najaf and Karbala Governorates oil seeps are used to assess the Jurassic Butmah, Sargelu, and Lower unit of Najmah formations in Kifle, West Kifle, Merjan, and Ekhaither fields western part of the Euphrates rivers. Plots of Roch-Eval pyrolysis analysis data of 334 source rock samples on van Krevlen, production index, and petroleum potential diagrams as well as 1D PetroMod software basin modeling of timing and extent of the hydrocarbon generation have confirmed the petroleum generation timing and their transformation ratios from these source rocks. The generated oil have possessed lateral migration along the upper unit of the Najmah Formation to the site of the Abo Jir major fault where it is changed to vertical migration along the fault that intersect with the ground surface. During the vertical migration path, impregnations of all the successive layers with heavy oil and asphalt have occurred. Main oil reservoirs of Cretaceous Nahr Umr and Harth formations and the Tertiary Dammam-Euphrates Formation were charged from this vertical migration path. The accumulated oils are of 15-38 API with 1.45-5.9 sulfur content in the Hartha Formation reservoir and 20-35 API with 0.9-3.7 sulfur content in the Nahr Umr Formation reservoir.