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Geochemical analysis of selected coals indicates that some of the Jurassic coals in Egypt have oil-generating potential. Other coals have just gas potential, but may have already generated oils as they are now post-mature for oil generation. Petrographic analysis of the coals reveals a composition dominated by vitrinite, but with variable liptinite contents and the occurrence of fluorescent vitrinite in some coals. It is not clear which components of the coal are responsible for the oil potential; it is probable that liptinite, hydrogen-rich vitrinites and a fine-grained groundmass of algal origin all contribute. A combination of Rock-Eval Hydrogen Indices and pyrolysis-gc P2 fingerprints provides the best method for determination of the oil- or gas-prone nature of the coals.
Attempts at correlating oils to source rock extracts illustrate the problem of oil-source correlations involving a rapidly varying source rock environment. The bitumen extracts from the coals reveal variable characteristics which reflect facies variations in the coals. Several of the coals have unusual saturated hydrocarbon and biological marker distributions that are atypical of humic coals and give a poor correlation to the waxy oils from the Meleiha field. The best oil-source rock correlation is with a carbonaceous shale, not a coal, but it is likely the oils were derived from large volumes of source rock including coals and carbonaceous shales. As the coals have unusual extract characteristics, any oils derived from a more localized environment in the coal swamp may show very unusual geochemical characteristics, and would not be recognized immediately as being derived from terrestrial coals.
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