TY - JOUR

T1 - Geochemistry of water-soluble gases in the oil and gas bearing sediments of the zone of junction between the yenisei-khatanga and the west siberian basins (The arctic regions of siberia)

AU - Novikov, Dmitry A.

AU - Borisov, E. V.

N1 - Funding Information: The studies were carried out with financial support from the Program of Fundamental Research under Projects No. 0331-2019-0017, 0331-2019-0025; from the Russian Foundation for Basic Research under Project No. 18-05-70074 Resources of the Arctic; from the Russian Foundation for Basic Research and the Government of the Yamal-Nenetz Autonomous District within research project No. 19-45-890005. Publisher Copyright: © 2021, Georesursy LLC. All rights reserved.

PY - 2021/11/30

Y1 - 2021/11/30

N2 - The results of the studies of geochemical and zoning features of water-dissolved gases in the Mesozoic sediments of the junction between the Yenisei-Khatanga and the West Siberian basins are reported. The stage of industrial oil and gas content is more than 3 km thick and involves the depth range from 750 to 4000 m. Waters occurring in the region contain methane, their total gas saturation is 0.3 to 4.6 dm3/dm3, and CH4 content in 88.9 to 95.4 vol. % on average. An increase in the concentrations of carbon dioxide and methane homologues is observed with an increase in the depth, which is accompanied by a regular decrease in the concentrations of methane and nitrogen. In general, water-dissolved gases from the Neocomian and Jurassic reservoirs have similar compositions (С1 > N2 > C2 > C3 > n-C4 > i-C4 > CO2 > i-C5 > n-C5). The water-dissolved gases of the Aptian-Albian-Cenomanian sediments are distinguished by lower concentrations of methane homologues (С1 > N2 > C2 > CO2 > C3 > i-C4 > n-C4 > i-C5 > n-C5), with the total content of heavy hydrocarbons (HHC) equal to 1.44 vol. %. Vertical zoning of the composition of water-dissolved gases is determined by the distribution of hydrocarbon pools in the Jurassic-Cretaceous section. A regular increase in the average values of the factor of enrichment with hydrocarbons (HC) (from 37 to 154) was established, along with a decrease in the ratio of CH4 /ƩHHC (from 130 to 7), C2 H6 /C3 H8 (from 41 to 2) and i-C4 H10 /n-C4 H10 (from 2.6 to 0.6) from the Aptian-Albian-Cenomanian reservoirs to the Jurassic ones. The zone with anomalous He concentrations within the range of 0.4–0.9 vol. % was detected in the Neocomian and Middle Jurassic sediments. This zone is localized at the north-western slope of the Messoyakh inclined ridge (the Anomalnaya, Turkovskaya, Pelyatkinskaya and Sredne-Yarovskaya areas). The nature of this anomaly needs further studies.

AB - The results of the studies of geochemical and zoning features of water-dissolved gases in the Mesozoic sediments of the junction between the Yenisei-Khatanga and the West Siberian basins are reported. The stage of industrial oil and gas content is more than 3 km thick and involves the depth range from 750 to 4000 m. Waters occurring in the region contain methane, their total gas saturation is 0.3 to 4.6 dm3/dm3, and CH4 content in 88.9 to 95.4 vol. % on average. An increase in the concentrations of carbon dioxide and methane homologues is observed with an increase in the depth, which is accompanied by a regular decrease in the concentrations of methane and nitrogen. In general, water-dissolved gases from the Neocomian and Jurassic reservoirs have similar compositions (С1 > N2 > C2 > C3 > n-C4 > i-C4 > CO2 > i-C5 > n-C5). The water-dissolved gases of the Aptian-Albian-Cenomanian sediments are distinguished by lower concentrations of methane homologues (С1 > N2 > C2 > CO2 > C3 > i-C4 > n-C4 > i-C5 > n-C5), with the total content of heavy hydrocarbons (HHC) equal to 1.44 vol. %. Vertical zoning of the composition of water-dissolved gases is determined by the distribution of hydrocarbon pools in the Jurassic-Cretaceous section. A regular increase in the average values of the factor of enrichment with hydrocarbons (HC) (from 37 to 154) was established, along with a decrease in the ratio of CH4 /ƩHHC (from 130 to 7), C2 H6 /C3 H8 (from 41 to 2) and i-C4 H10 /n-C4 H10 (from 2.6 to 0.6) from the Aptian-Albian-Cenomanian reservoirs to the Jurassic ones. The zone with anomalous He concentrations within the range of 0.4–0.9 vol. % was detected in the Neocomian and Middle Jurassic sediments. This zone is localized at the north-western slope of the Messoyakh inclined ridge (the Anomalnaya, Turkovskaya, Pelyatkinskaya and Sredne-Yarovskaya areas). The nature of this anomaly needs further studies.

KW - Gas saturation of groundwaters

KW - Gas zoning

KW - Methane homologues

KW - The Arctic

KW - The Yenisei-Khatanga basin

KW - Water-dissolved gases

KW - West Siberia

UR - http://www.scopus.com/inward/record.url?scp=85121971463&partnerID=8YFLogxK

UR - https://www.elibrary.ru/item.asp?id=47544432

UR - https://www.mendeley.com/catalogue/9d1ae12d-334c-3804-9e5d-5b2873c6c477/

U2 - 10.18599/grs.2021.4.1

DO - 10.18599/grs.2021.4.1

M3 - Article

AN - SCOPUS:85121971463

VL - 23

SP - 2

EP - 11

JO - Георесурсы

JF - Георесурсы

SN - 1608-5043

IS - 4

M1 - 1

ER -