Source rock potentiality and maturation of organic matter are important for petroleum system evaluation. Oil to source correlations helps in determining migration pathways. A set of geochemical analyses, including Rock-Eval pyrolysis and gas chromatography, and burial history modeling have been used to evaluate the potential source rocks and the generation of hydrocarbons in northern Shushan Basin, Western Desert of Egypt. The cutting and core samples cover the section from the Middle Jurassic Khatatba to the Upper Cretaceous Abu Roash formations. The main objective of this study is to determine source rock potential and maturity, the timing of hydrocarbon generation, and to characterize and correlate the bitumen extracted from Alam El-Bueib (AEB) and Khatatba rocks with the oil recovered from Bahariya reservoir. Results show that only a thin interval in AEB-3A and AEB-3C units are capable of generating moderate amounts of gas with some oil. Unlike other parts of the northern Western Desert, the older Khatatba rocks do not appear to contain significant amounts of good quality Kerogen. The Bahariya reservoir oil was derived from mixed organic matter source (algal-terrestrial) and is mature. It is believed that Bahariya oils were sourced from AEB rocks with a minor contribution, if any, from the Khatatba Formation. The normal faults dissecting the area act as migration pathways from deeply seated source rocks to more shallow reservoirs.
The Shushan Basin includes many old oil and gas fields in the north Western Desert of Egypt. Khalda oil Field lies approximately 460 Kms. West of Cairo and 70 Kms. south of the Mediterranean Coast (EGPC 1992, Schlumberger 1995). It lies at the northeastern part of the Shushan Basin in the Western Desert (Fig.1). It was discovered in November 1980 by drilling Khalda-1X well. In 1984, Khalda-2 well was drilled and proved the southern extension of Khalda Field. Currently, Khalda oil Field is under development with up to 100 producing and injector wells. The northeastern margin of Shushan Basin is controlled by NE-SW trending faults, offset by later NW-SE wrenching. These faults throw Mesozoic rocks against older strata. The structure on top Bahariya Formation is an oval anticline, dissected by NW-SE trending normal faults. Minor faults (< 50 ft. throw) offset the Bahariya Formation and isolate the pay zone into several fault blocks within the field (Fig.2). Bahariya Formation is the main oil-producing reservoir and composed of sandstone alternating with shale and siltstone streaks, with minor limestone and dolomite. It is divided into Upper and Lower Bahariya members.