BIOMARKER CHARACTERISTICS OF OIL AND SOURCE ROCKS FROM THE SENONIAN–EOCENE SUCCESSION, BELAYIM OILFIELDS, CENTRAL GULF OF SUEZ, EGYPT (original) (raw)

This study aims at assessing the hydrocarbon source rocks of the Belayim oilfields, central Gulf of Suez, Egypt through detailed geochemical methods, to characterize organic-rich facies of the Senonian-Eocene deposits. Liquid chromatography, gas chromatography and gas chromatography- mass spectrometry are the methods used in this study. In order to throw light on the organic matter source, composition, and thermal maturity, 4 crude oil samples are analyzed using C7 and stable carbon isotopes in addition to some techniques applied on the extracts. The source rocks are mainly derived from algae and bacteria with a minor contribution of terrestrial organic sources mainly clay-poor source rocks, deposited under normal saline and reducing paleoenvironmental conditions. This is evidenced by the n-alkanes distribution, pristane/phytane, homohopane, gammacerane index and the high concentration of cholestane, the presence of the C30 n-propylcholestanes and low diasteranes ratios. The source rock extracts range from immature to marginally mature, based on biomarker maturity-related parameters. A similar scenario is envisaged to the studied crude oil samples which showed a partial positive correlation with the source rocks of the Eocene Thebes Formation, and the Upper Senonian Brown Limestone. Our data pinpointed that the Lower Senonian Matulla Formation samples may trigger some oil in the study area.