An estimation of the magnitude and spatial distribution of potential Black Sea methane hydrate reservoirs have been made based on 6×6 minute (in longitude and lattitude) data grid. The general input includes bathymetry; bottom temperatures; heat flow (487 quoted in situ measurements are considered); temperature gradients; thermal conductivity of the sediments; pressure-temperature hydrate phase relations; organic carbon content as function of depth; sediment porosity-depth curves; percentage of hydrate occupying the hydrate stability zone; and volumetric gas expansion factor.
The estimations are based on the two main theories of gas hydrate formation — in situ bacterial production and pore fluid expulsion models. The spatial evaluation of the most probable gas hydrate distribution is also discussed.
The calculations show that average water depth from which methane hydrate start to forms in the Black Sea ranges from 620 m to 700 m embracing a prone area of 288,100 km2, representing 91% of the deep Black Sea basin. The average thickness of the MHSZ is 303 m with a bulk of sediment ranging from 85,310 to 100,280 km3. The evaluations set the hydrate content on 77–90 to 350·109 m3 or about 10 to 50·1012 m3 of gas methane are trapped within the Black Sea sediments in the form of hydrate.