Maturation Assessment of Oils and Condensates from Abu El Gharadig Basin, Western Desert, Egypt

By

 Alaa El-Din R. Mostafa¹, Assem O. Barakat¹, Yaorong Qian², Moonkoo Kim², Mahlon C. Kennicutt II²

(1) Alexandria University, Alexandria, Egypt (2) Texas A&M University, Texas, TX

 Analyses of seven oils and condensates from three fields in Abu Ghradig basin in the Western Desert of Egypt indicated that fluid phase and hydrocarbon compositional variations in Upper and Lower Cretaceous reservoirs were related to maturity levels of source rocks. Maturity parameters such as 4-MDBT/1-MDBT, dimethyl dibenzothiophenes (DMDBT), MPI3 and DNR ratios of aromatics correlate well with maturity indicators based on saturate fractions of petroleum. Molecular parameters of aromatic sulfur compounds work well over a wide range of catagenesis, showing no reversal at the advanced levels of thermal evolution and can efficiently discriminate very mature petroleum. The abundance of dibenzothiphenes of the oils is comparable to fluorenes and phenanthrenes. This distribution of PAH is typically characteristic for siliciclastic. The ratio of DBT/P, calculated as the ratio of the sum of all dibenzothiophenes and all phenanthrenes, ranges between 0.39 and 0.73 (average 0.5), which is also distinctive for siliciclastic sediment sourced oils. The comparable PAH distributions in all oils and condensates presumably reflect that they have been generated from a similar source rock under consistent depositional conditions.