A.I. Gresov, A.V. Yatsuk, N.S. Syrbu, A.K. Okulov
Gas-geochemical zoning of seafloor formations of sedimentary basins and geostructures of East Siberian Sea and Arctic Ocean outer shelf
Key words: seafloor formations; gas saturation; isotope and gas-geochemical indicators; gas genesis; geological factors; East Siberian Sea; Arctic Ocean.
For citation: Gresov A.I., Yatsuk A.V., Syrbu N.S., Okulov A.K. Gas-geochemical zoning of seafloor formations of sedimentary basins and geostructures of East Siberian Sea and Arctic Ocean outer shelf. Geologiya nefti i gaza. 2021;(5):107–122. DOI: 10.31087/0016-7894-2021-5-107-122. In Russ.
Funding: Gas-geochemical studies funded by the Russian Foundation for Basic Research grant No. 18-05-70038 “Arctic resources” within the scope of the statedefined topic No. 0211-2021-0006 (121021500055-0). Marine fieldworks (trips LV-77 and LV-90) are funded by the Ministry of Education and Science of the Russian Federation, China National Natural Science Foundation NSFC-Shandong (grants No. U1606401 and No. 41420104005), grant of Marine S&T Fund of Shandong Province (No. 2018SDKJ0104-3), and the National Program on Global Change and Air-Sea Interaction (Project No. GASI-GEORGE-04).
Methane and its homologues, hydrogen, helium, carbon monoxide and dioxide, hydrogen sulfide, argon and nitrogen are found in the seafloor formations of sedimentary basins and geostructures in the central part of the outer shelf of the East Siberian Sea and the Arctic Ocean. In the process of the research, gas saturation of sediments and isotope-geochemical indicators of gas genesis from various gas sources were determined. It is found that the gas phase of seafloor formations is mainly composed of epigenetic gases from underlying geological formations, namely: supposed coal and gas formations, igneous formations, solid bitumen, condensate and gas, gas and condensate, oil and gas, gas and oil, and oil accumulations and pools. It is determined that gas saturation and gas-geochemical zoning of seafloor formations depend on the mixed influence of the main gas-controlling factors, they are: geological structure; fold and fault tectonics; oil and gas occurrence; lithological composition and saturation with Organic Matter; permafrost-related, hydrodynamic and other conditions of formation; gas accumulation or draining-out of gas. Basing on the analysis of data obtained, the informative value of the gas-geochemical method for hydrocarbon exploration and petroleum potential of the study area were assessed.