Spatial and quantity evaluation of the Black Sea gas hydrates

An estimation of the magnitude and spatial distribution of potential Black Sea methane hydrate reservoirs have been made based on 6X6 minute (in longitude and latitude) 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 km (super 2) , 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 km (super 3) . The evaluations set the hydrate content on 77-90 to 350X10 (super 9) m (super 3) or about 10 to 50X10 (super 12) m (super 3) of gas methane are trapped within the Black Sea sediments in the form of hydrate.