Isotopic-Geochemical Characteristics of Organic Matter and Hydrocarbon Fluids from the SCB Productive Series. Oil-Rock Relationships

Hydrocarbon extracts of source rock and oil and gas samples were analyzed using gaschromatography, mass spectrometry, and their combination (biomarker analysis). Oil–oil, and oil–source rock correlations areused. The values of the complex biomarker parameters of collected oil samples correspond to Tertiary source rocks with similarorganic facies accumulated in deep-water conditions with some terrestrial contribution. Oils have low to moderate organicmaturities (Ro = 0.75–0.85). The relationship between the isotope composition of carbon (ICC) for aliphatic and aromaticfractions of oils and rock extracts (oil-rock correlation) shows that the source of commercial oil reserves in the Productive series(lower Pliocene) is mainly Miocene deposits (Diatom, Chokrak, and Upper Maykop strata). The source of gases is from thesedimentary cover, as evidenced by the 3He/4He ratio values. They also have been derived from mixed marine organic-richsource facies.