Molecular Geochemistry of The Palaeozoic Source Rocks and Oils from Ghadames Basin, North West, Libya

A detailed molecular geochemical investigation of the source rocks and reservoired oils from Al-hamada field complex, (NC5, NC8), Al-Wafa field (NC169) and (NC3) throughout the Ghadames basin has revealed that all the oil samples display similar facies features to the Lower Silurian source rocks. There is a high probability that these oils were generated from the Lower Silurian 'hot shale' source rocks. Maturity evaluation of the oil samples based on the biomarker and aromatic hydrocarbon ratios indicates that the oil samples collected from the oil fields located in the South and southwestern parts of the basin are more mature than the oil samples collected from the northern parts of the basin. This is in consistent with the maturity trends of the source rocks of the Ghadames Basin.<br>Most of the Upper Devonian source rock samples have unusual proportions of the 20S isomers (relative to 20R isomers) of the C29 steranes, with values of more than 55% 20S. Such high values could be due to factors other than maturity.<br>