عنوان مقاله [English]
In this research, in order to investigate the geochemical characteristics of oil samples collected from Asmari and Sarvak reservoirs in one of the oil fields in the northwest of the Persian Gulf, methods and techniques of SARA test, gas chromatography, gas chromatography-mass spectrometer and carbon isotope analysis were used. Based on the results, it seems that the studied oil samples are the same in terms of chemical composition, and except for a small difference in the aromatic, resin and asphaltene fractions, no significant difference is observed in the hydrocarbon fractions of these oils. Also, in order to investigate the sedimentation environment conditions of the source rock producing these oils, the ratios of Pr/ Ph and Pr/ Ph versus CV or standard variable and the curve of changes in Pr/nC17 parameter against Ph/nC18 have been used. The results indicate that all the oil in two reservoirs was produced from the same source rock with an open sea facies and probably deltaic environment. In addition, the investigation of the maturity indices of the aromatic, hopane and aromatic biomarkers related to the oil samples of both formations showed the same characteristic and indicates a degree of maturity in the early to middle of the oil generation window. Accurate biomarker studies indicate the Jurassic age and older for the studied oil producing rocks. Therefore, it can be said that the accumulated oils in the Asmari (Ghar) and Sarvak reservoirs of this field originated from the same formation with the same sedimentation conditions.