V. A. Solov'ev
Keywords: Gas hydrates, methane, quantitative assessment, gas hydrate accumulations, models for accumulation formation, potential gas-hydrate-bearing water areas, World ocean
Pages: 648-661
Based on the concepts of occurrence of submarine gas hydrates as accumulations and on the general regularities of changes in their densities, global assessment of gas amount in gas hydrates of the World ocean is given. It is shown that the shape and the size of gas hydrate accumulations are controlled either by a concentrated flow of gas-containing fluids through the zone of gas hydrate stability and by parameters of their scattering halo or by a dissipated flow of gas-saturated water depending on fluid guides and lithologic peculiarities of the deposits. Geologo-geochemical and geophysical data on 10 best studied accumulations of gas hydrates were analyzed. The average specific (per unit area) content of gas in studied gas hydrate accumulation has been obtained, ca. 6.5

108 m
3/km
2. The specific gas content in gas hydrates within all potential gas-hydrate-bearing water areas is ca. 5

106 m3/km2. According to data of performed mapping, the total area of these water areas is about 35.7 mln km
2, i.e., ca. 10% of the area of the World ocean. The total amount of gas, mainly methane, in the world's submarine gas hydrate accumulations is estimated at ca. 2

1014 m
3.