ASSESSMENT OF THE ACCUMULATION OF GAS HYDRATES UNDER THE GLACIER COVER

Abstract

. The possible accumulation of gas hydrates during the periods of glaciation was estimated taking into account the processes of gas filtration. Model calculations have shown that the rate of hydrate accumulation depends on the height of the ice sheet, thermophysical and hydrophysical properties of the soil, as well as the temperature regime of the soil. The influence of different values of the thickness of the ice sheet (from 200 to 500 m) and the temperature of the soil surface under the ice sheet (from –5 to 0 °С) was modeled. With an ice sheet thickness of 200 m and a basal temperature of about –2 °C, the stability zone of gas hydrates can spread from 10 m and reach 180 m. With an ice sheet thickness of 500 m, the stability zone can begin from the ground surface and reach 200 m even at a glacier base temperature of about 0 °C. When the thickness of the ice sheet is less than 200 m and the temperature of the base of the glacier is about 0 °C, equilibrium thermobaric conditions are not achieved and the accumulation of gas hydrates in the pore space in the upper 200 m soil layer does not occur. Estimates of hydrate accumulation under glacial cover due to fluid filtration are 0.1 % for thawed and 0.05 % for frozen soil per year.