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In northwestern Egypt, the upper Khatatba Formation shows dual reservoir and source rock characteristics in the Abu Gharadig and Shushan basins due to the lateral intrabasinal facies changes and different tectonic evolution. However, in the Matruh Basin, its petroliferous characteristics are not fully explored yet. Thus, integrated palynological and geochemical analyses were carried out on selected 15 shale and carbonate samples from the Middle Jurassic Zahra and upper Safa members of the upper Khatatba Formation from OBA 2-2A well in the Matruh Basin. The Zahra Member has poor to fair (0.32-0.64 wt % TOC) source rock potential, while the underlying upper Safa Member has very good to excellent (1.33-7.40 wt % TOC) source rock potential. Prevalence of brown phytoclasts and low Hydrogen index (HI: 46-146 mg HC/g TOC) indicates the occurrence of gas-prone organic facies (Kerogen type III), which reached the late oil-window and early gas-window stages as is evidenced by the Tmax (443-468 °C) and thermal alteration index (TAI: 3 to 3+) values. Analysis of preliminary results suggests the mature gas-prone shales of the upper Safa Member probably sourced the hydrocarbons that are proven by the drilling company to be accumulated in the sandy lower Safa Member reservoir. Analysis of the well logs using the Single-Device and Double-Device methods and ∆Log R technique will be utilized to calculate the organic richness of the studied section and calibrated by the pyrolysis-estimated geochemical data. Burial and thermal history modelling will be carried out to identify the generative interval, explore the effect of the regional tectonics on thermal maturation of the organic matter, and identify the timing of the hydrocarbons generation.

Recent national and international demand for additional resources of the fossil fuel resulted in extensive hydrocarbon exploration activities in Egypt to further explore possible petroliferous rock units that were conventionally deemed as barren or having non-commercial reserves such as the Alam El Bueib Formation. This increased the stress to enrich the lithological correlation of this formation across the north Western Desert to better understand its regional lithological characteristics and thus its potential regional reservoir/source rock quality. Palynostratigraphic analysis of Lower Cretaceous successions in the Tut-1X and Amoun-1X wells in the Shushan Basin, north Western Desert enabled the recognition of the upper Alam El Bueib Formation in both wells, in contrast to a previous study, which suggested non-deposition of this formation in the Amoun-1X well. This highlights the important role of the palynology as a key stratigraphic tool, which helped effectively in recognising this problematic monotone clastic formation, where other marine microfossils are lacking. This also shows that recognition of this formation based on lithological criteria only was impractical and misleading. Marker terrestrial and marine palynomorph taxa recovered from the upper Alam El Bueib Formation enabled dating it as late Barremian–early Aptian and were used to identify two palynological biozones that can be traced out regionally across the Shushan, Matruh, and other nearby basins. These biozones are the early Aptian Murospora florida–Afropollis operculatus–Pseudoceratium securigerum Assemblage Zone and the late Barremian Stellatopollis barghoornii–Pseudoceratium anaphrissum–Cyclonephelium vannophorum Assemblage Zone. An undifferentiated interval was recorded just below the upper Barremian strata in the Tut-1X well due to very low palynomorph recovery and absence of marker forms. Composition of terrestrial and marine palynomorph assemblages suggests the upper Alam El Bueib Formation was deposited in fluvio–deltaic to proximal inner shelf settings. The Alam El Bueib Formation shows notable regional variations in thickness and considerable lateral and vertical changes in lithology due to local tectonics and relative difference in its depositional settings in the Shushan and Matruh basins. Regionally, the Alam El Bueib Formation shows dual reservoir/source rock characteristics, where thick and poorly fossiliferous sandstone units act as reservoir rocks, while moderately fossiliferous finer clastics and carbonates already acted as intraformational source rock intervals in some parts of the Shushan and Matruh basins.

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