The offshore Nile Delta is an established and significant gas and condensate province in North Africa. It is considered to have significant remaining hydrocarbon potential for future exploration. The main petroleum system comprises of an Oligocene Type II/III mixed oil and gas prone source rock which charges the overlying thick sequence of Neogene-Quaternary clastics. While the hydrocarbon potential of the Nile Delta and its geological and stratigraphic pattern has been the focus of numerous studies, the origin of the gas and associated fluids has been poorly documented.
In order to characterize the natural gas at the study area, an integrated geological, geophysical and geochemical study was performed on 439 gas samples and 493 cutting samples collected from 7 wells in addition to a review of published work covering the origin of natural gas and associated fluids.
The analysis shows that the gases are dominated by methane (97%-100%) and the light carbon isotopic composition (δ13C1) values (−57.4‰ to −80‰) suggest that these gases are derived from the decomposition of immature (0.3-0.6 Ro%) sedimentary organic matter by Methanogens activity under relatively low temperatures (<80°C).
The paper will give an overview of the integrated work, focusing on the geochemical analysis used to describe the occurrence and character of the natural gases in the study area.