Title : Paleozoic petroleum system in the Marzuq Basin
Abstract:
In the Southwest Libya area, the Paleozoic deposits are an important petroleum system, with Silurian shale considered a hydrocarbon source rock and Cambro-Ordovician recognized as a good reservoir. The Palaeozoic petroleum system has the greatest potential for conventional and thought to be representing the significant prospect of unconventional petroleum resources in Southwest Libya. Until now, the lateral and vertical heterogeneity of the source rock has not yet been evaluated, and oil-source correlation is still a matter of debate.
To assess the petroleum potential qualitatively as well as quantitatively, uranium contents of an only source rock the main source potential in the Marzuq Basin investigated via bulk kinetic characteristics of organic petrography, rock-eval pyrolysis, and gamma-ray logs. To identify acyclic isoprenoids and aliphatic, aromatic, and NSO biomarkers, thirty source rock samples and fifteen oil samples from the Tanezzuft source rock have been subjects to Rock-Eval Pyrolysis, microscopely assessment, GC, and GC-MS analyses. For finding age a significant biomarkers and sources of high-spot genetic relationships, geochemistry tools applied.
A grating heterogeneity exists among source rock zones from various levels of depth with varying uranium contents according to gamma ray logs, rock-eval pyrolysis results, and kinetic features. The uranium-rich Tanezzuft Formations (Hot Shales) produce oils and oil-to-gas hydrocarbons based on their richness, kerogen type, and thermal maturity. Biomarker results such as C27, C28, and C29 steranes concentrations and C24 tetracyclic terpane/C26 tricyclic terpane ratios, with sterane and hopane ratios considered the most promising biomarker information in differentiating within the Silurian Shale Tanezzuft Formation and in correlating with its expelled oils.
The primary source rock for oil and gas accumulations in the Cambro-Ordovician reservoirs of the Marzuq Basin thought to be the Tanezzuft Formation (Hot Shale).
The Cambro-Ordovician petroleum system's reservoirs thought to have supplied with generated and expelled oils and gases from the Tanezzuft source rock through vertical and lateral pathways along the faults in the Palaeozoic Strata. In the Marzuq Basin, the Upper Tanezzuft Formation (cold shale) is the main seal.
