Comparative characterization of natural hydrocarbon systems of various genesis

Abstract

Genetic diagnostics of hydrocarbon systems of different origins—hypergenetically altered (biodegraded) and immature fluids—has been performed in terms of hydrocarbon (HC) and trace element (TE) indicators. Among more than 30 hydrocarbon compounds and more than 10 trace elements, informative and universal discrepancy criteria have been selected. These are the 20S/(20S + 20R) and ββ/(ββ + αα) C₂₉ sterane ratios; the diasteranes/regular steranes ratio; and the oleanane/C₃₀ hopane (H₃₀), moretane/H₃₀, and gammacerane/H₃₀ hydrocarbon biomarker ratios. Type assignment of crude oils in terms of trace element content has revealed significant differences of hypergenetically altered oils in the total cycle of naphthidogenesis and showed that they are oils of secondary enrichment with trace elements (V/Ni > 1), creating vanadium metallogenic provinces with hydrocarbon deposits enriched in V, Ni, U, Mo, etc. at a commercially viable level.