Organic source of crude oils and 1D basin modeling of upper Cretaceous rocks, Badr Concession, Abu Gharadig Basin, Western Desert, Egypt

Abstract

The Badr Concession exists in Abu Gharadig basin, which is a great oil province in Western Desert, Egypt. This work concerned on studying the geochemical characteristics and organic source of crudes produced from Abu Roash “C” (AR/C) Member in BED15-1, BED15-3, and BED15-4 wells using gas chromatography (GC) analysis. Also, the BasinMod Software is used to construct models of burial history that detect thermal maturity and generation timing for Cretaceous sources based on modeled Vitrinite reflectance (%Ro). The oil samples are not biodegraded, due to the existence of an intact paraffin envelope in all three oils as revealed from low normal-alkane/isoprenoids and the distribution of different light hydrocarbons. These crudes have pristane/phytane (Pr/Ph) ratio that ranged from 1.03 to 1.08 indicating that those oils are generated from mixed organic matter such as algae and submerged macrophyts which are the main constituents which are deposited and preserved in lacustrine environment under reducing to suboxic condition. The Pr/nC17 and Ph/nC18 ratios indicate that these crudes are mature. Also, the models of burial history indicate that Abu Roash Formation reached mid maturation stage and these results are in agreement with GC results. Generally, the hydrocarbon generation began in Late Cretaceous and reached the peak during the Tertiary.