AN ORGANIC GEOCHEMICAL INVESTIGATION OF CRUDE OILS FROM EGYPT

Conventional organic geochemical and biomarker parameters are used tog ether to provide information on source organic matter input, depositio nal environment, and the correlation between crude oils from different pay zones and geographical locations in Egypt. The method of biomarke r characterization is based on the fractionation of crude oils by liqu id chromatography into three main compound classes: saturated hydrocar bons, aromatics and N, S, O components. The identities of specific com pounds and the carbon number distribution of n-alkanes and acyclic iso prenoids were determined by capillary column gas chromatography. On th e basis of correlation plots between biomarker and nonbiomarker parame ters, the oil samples are classified into three main groups. The first group includes oil samples from the central part of the Gulf of Suez (Balayem Land, Bakr, Gharib and July fields) and is typical of crude o ils generated in a strongly reducing environment. The second group com prises oils generated from sediments deposited in suboxic conditions a nd includes oils from the south central and southern part of the Gulf (Ras Fanar, Shark El-Zeit, Amal 9, Amal 10 and Gamma) and Yidma crude from the Western Desert. The third group includes oil samples of the W estern Desert from the Umbaraka, Khalda and Meleiha fields, which are typical of oils accumulated under oxic palaeoenvironmental conditions. (C) 1997 Copyright Elsevier B.V.