الفهرس 
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Abstract
The present study focuses on Concession 11, which is located in the Zallah Trough in the western Sirte Basin. This concession includes many giant oilfields. In order to improve our understanding of this area and to provide a source rock evaluation of the poorly studied Upper Cretaceous-Paleogene successions, detailed sedimentological, mineralogical, organic geochemical, palynological and palynofacies analyses have been undertaken on a number of wells to investigate the petroleum potential and depositional environment of Upper Cretaceous-Paleogene rock units, define the genetic relationships between these source rocks and the crude oil samples studied, determine the role of the investigated source rock units in charging the hydrocarbon reservoirs in the study area and classify the oils and source rocks into genetic families. Fifty-six cores and cuttings samples from shales in the Campanian Sirte Formation and from other Upper Cretaceous deposits that are believed to be the most important source rocks in the Sirte Basin have been analysed using different techniques. These included detailed organic-geochemical, biomarker and stable isotope studies, and were complemented by the analysis of eight oil samples from Paleocene-Eocene reservoir units in nearby wells. The organic matter consists of Types-II and II/III kerogen. The source rocks are interpreted to be immature/early mature in terms of hydrocarbon generation and to reflect deposition in a weakly reducing to suboxic setting as revealed by the combined evidence of geochemical and palynofacies data.Existing organic geochemical analyses involving Rock-Eval pyrolysis and total organic carbon (TOC) measurements were supplemented by palynofacies, microfacies, and mineralogical analyses to interpret the depositional regime, and the palaeoenvironmental and thermal maturation history of the successions studied.This evolved into a shallow, near-shore, inner shelf marine environment under proximal-distal suboxic-anoxic conditions, as evidenced by palynofacies, mineralogical and microfacies analyses of the Upper Cretaceous Rachmat, Sirte and Kalash formations. Geochemical analyses suggest that all of the oil samples are of the same genetic type and originated from the same or similar source rock(s). Based on their bulk geochemical characteristics and biomarker compositions, the oil samples are interpreted to be derived from mixed aquatic algal/microbial and terrigenous organic matter.