Earth’s Cryosphere, 2019, Vol. XXIII, No. 6, p. 16-22

METHANE AND CARBON DIOXIDE HYDRATE STABILITY ZONES IN THE SEDIMENTARY COVER OF THE VILYUI SYNECLISE

A.D. Duchkov1, M.N. Zheleznyak2, L.S. Sokolova1, V.P. Semenov2

1 Trofimuk Institute of Petroleum Geology and Geophysics, SB RAS,
3, Akad. Koptyug ave., Novosibirsk, 630090, Russia; duchkovad@ipgg.sbras.ru
2 Melnikov Permafrost Institute, SB RAS,
36, Merzlotnaya str., Yakutsk, 677010, Russia

Results of determining the gas hydrate stability zone boundaries for methane and carbon dioxide hydrates at 46 sites within the Vilyui syneclise sedimentary basin are presented. The geothermal data and phase diagrams representing hydrate formation conditions in the CH4–H2O and CO2–H2O systems were used as the basis for the proposed methods for calculating positions of the gas hydrates stability zone boundaries. These data allowed constructing schematic representation of the lower boundary of methane hydrates stability zone within the entire Vilyui syneclise and its position along the latitudinal profile through the Khapchagai megaswell. The research results convincingly demonstrated that there are favorable conditions for the gas hydrates formation (e.g. sandy sections, high concentrations of dissolved methane in groundwater throughout the section, and considerable thicknesses of gas hydrates stability zones) in the sedimentary cover of the Vilyui syneclise.

Vilyui syneclise, permafrost zone, methane and carbon dioxide hydrates, gas hydrate stability zones

DOI: 10.21782/EC2541-9994-2019-6(16-22)