Gas geochemical indicators of oil and gas occurrence in south-eastern part of East Siberian Sea

Data of gas geochemical studies of core taken from bottom sediments in shallow wells and with the use of piston coring are presented for south-eastern sector of the East Siberian Sea. Composition and isotope and geochemical indicators of hydrocarbon gases are determined in sediments of different lithotypes and gas source rocks. Identification of syngenetic and epigenetic (migration) hydrocarbon gases is carried out for bottom sediments of the study area on the basis of the data obtained and other materials. Areas of gas occurrence in the present-day sediments, coal beds, igneous formations, gas and anticipated condensate-gas, gas-condensate, bitumen, oil-and-gas, gas-and-oil, and oil accumulations and pools are delineated. Key geological factors influencing the processes in bottom sediments, which cause formation of gases having different genesis are determined. The authors prepared the schematic maps of gas geochemical indicators distribution and expected oil and gas bearing areas. The authors evaluated the petroleum potential of the study area in geological and gas geochemical context