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The Kupal oil field is located in the north of Dezful Embayment in southwest of Iran. The purposes of this study were correlations between the Sarvak and Asmari reservoirs oils in the Kupal oil field and determining the source of oil in this field. In order to achieve these objectives, different geochemical methods, including Rock Eval, gas chromatography, gas chromatography-mass spectrometry, and carbon isotope analyses of asphalthene in oils and source rocks, were used. The results of pyrolyzed possible source rocks of the Kupal and its near fields by the Rock Eval apparatus indicated good source rock potential for the Kazhdumi and Pabdeh formations. In addition, Kazhdumi formation in the Haft-Kel oil field indicated gas production potential while the samples of the Gurpi formation were in a non-source rock zone. The Asmari and Bangestan reservoir oils had the same components and geochemical characteristics, except the Sarvak (Bangestan) reservoir oil in the Kupal field contained Oleanane biomarkers, whereas Asmari reservoir oil had no Oleanane biomarker. This fact was attributed to the fault in the southwestern part of the Kupal oil field, which moved the Pabdeh formation (in which its oil contains Oleanane biomarkers) to more depths and near the Sarvak formation. This movement caused the maturation of Pabdeh formation and migration of the produced oil to the Sarvak reservoir. [ABSTRACT FROM PUBLISHER]

Considering all different formations in Zagros Basin, the Cretaceous column has a remarkable position. Fahliyan Carbonate Formation with the age of Neocomian (Lower Cretaceous) is a main reservoir of Khami Group and is extended in whole Zagros Basin. Considering Fahliyan performance as a high-quality reservoir and Marun Oil Field as one of the top biggest oil fields in Dezful Embayment, southwest Iran, a detailed study looked quite necessary in this area. This research was mainly done based on petrographic methods. Moreover, well logs were used as a subsidiary tool to assess the reservoir potential of microfacies. After recognition of microfacies and evaluation of lateral and vertical variations (using Walter's law), the depositional model of Fahliyan Formation was proposed. At the final stage, compartments with more reservoir potential were proposed. Generally speaking, the main tasks done through this study are study of different kinds of microfacies, study of diagenetic processes, study of depositional environment, and assessment of microfacies with reservoir potential using thin sections and well logs. [ABSTRACT FROM PUBLISHER]

Well logging is a useful method for sedimentary basin and source rock evaluation. Source rocks have special responses in porosity and resistivity logs that can make them distinguishable from surrounding rocks. Therefore, well logging data and diagrams can be used as indicators of determination of source rock potential. Characterizations of Kazhdomi, Pabdeh, and Gurpi source rocks have been determined by geochemical analysis in some Iranian oilfields, but no total organic carbon (TOC) zonation and interpretation have been carried out in these formations yet. Several studies have confirmed the petroleum potential of the Kazhdomi formation in Dezful Embayment, but Pabdeh formation (more significant) and Gurpi (less significant) have been always the topics of Iranian petroleum geologist discussions in order to deermine whether these formations have the potential of generating oil and what the organic matter properties of these formations are. The purpose of this article is to calculate TOC values of the Pabdeh formation in Ahwaz and Marun oilfields using a combination of sonic and resistivity logs (ΔlogR method) and a neural network method. Then these TOC values were compared with TOC from geochemical analysis. Finally, the zonations of source rock in terms of TOC richness were carried out and TOC changes in the oilfields were shown by plotting Iso-TOC maps. It was found that due to the high local temperature gradient Pabdeh reaches an oil window level in some parts of Ahwaz and Marun oilfields. Hence, Pabdeh acts as a source rock for these two oilfields in some sections. [ABSTRACT FROM AUTHOR]