Hydrocarbon potential of the Albian-early Cenomanian formations (Kharita- Bahariya) in the North Western Desert, Egypt: A review.

Rock-Eval pyrolysis/TOC, petrographic, and geochemical data available in the public domain for a total of 296 core and 243 drill cuttings samples from the Albian-early Cenomanian Kharita and Bahariya formations of four main basins, Shushan, Abu Gharadig, Matruh and Dahab-Mireir, were reviewed. This review provides a comprehensive overview to understand the organic richness, type, and thermal maturity of potential source rock intervals within the Kharita and Bahariya formations in northern Egypt by means of burial history modeling and oil-in-place calculations. Geochemical data of both formations confirmed the presence of up to excellent source rocks of varied kerogen types but mainly of Type III (gas-prone) and mixed types II/III. Thermal maturity levels ranged from immature to the early stage of oil window, although some intervals reached the peak oil window in the Abu Gharadig and Shushan basins compared to their counterparts. The depositional paleoenvironment of the Kharita and Bahariya formations is interpreted based on the organic biomarker compounds and palynofacies associations. Generally, both formations in the four basins were interpreted to accumulate in a fluvio-deltaic to marginal marine setting, although the Kharita rock unit was slightly less marine based on the isoprenoids pristane and phytane to nC 17 and nC 18 ratios. The ratio of 22S/(22S + 22R) for the homohopanes C 31 and C 32 of Kharita oils from the Shushan Basin ranged from 0.50 to 0.60, indicating marginally mature to the onset of oil generation. However, common amongst much of the previous studies was the notable differences in organic matter contents, thermal maturity levels and hydrocarbon potential. Environmental and ecological processes, including proximity to shoreline, terrestrial/riverine input, oxygenation levels and water column conditions, are considered the primary drivers that triggered variable amounts of organic carbon accumulation. While differences in thermal maturity levels were attributed to tectonic activities and related structural processes. • Fair to good organic matter-richness in the Bahariya and up to excellent for the Kharita Formation was reported. • The source rock beds within the both formations have variable kerogen types (Type III, II/III and II). • Levels of maturation in both formations were mainly immature to early mature with minor intervals in peak stage of oil window. • The Kharita and Bahariya formations had the highest yield of oil‐in‐place in the Matruh Basin. • Despite the Kharita was less marine than Bahariya, both formations were deposited in fluvio-deltaic/marginal marine settings. [ABSTRACT FROM AUTHOR]