Correlation of source rocks and crude oils in Kupal and its near oil fields,SW of Iran

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.