A comprehensive study of the origins of methane emission in the Black Sea

Search and exploration of hydrocarbon deposits of sea and ocean floors is one of the most urgent problems of the modern marine geology. In Ukraine the problem of scientifically reasoned evaluation of reservoirs and specification of the prospects of natural gas production is highly important. However, a key question of the origin of the gas seepage and seabed flames remains controversial and has not yet been clarified.

Materials for the study were compiled by an expedition of Department of Marine Geology and Sedimentary Ore Formation of Ukrainian National Academy of Sciences using a manned submersible in combination with conventional methods of marine geology. On the basis of this data, we analyzed the outside edge of the shelf, the continental slope, the adjacent area of the Black Sea basin and confirmed both endogenous and biogenic origins of natural gas at the sea floor. The study discloses specific tectonic and geodynamic conditions of the Cenozoic era, high fragmentation of the region, a frequent renewal of permanent fault systems that promotes an active lateral and vertical migration of large masses of hydrocarbons in the Earth's crust. The study found that the North Black Sea coast is a zone of active accumulation of natural hydrocarbons of various origins. As the next step of the studies, a detailed tectonic analysis can provide a substantial assistance to determine the prospects of developing energy resources and to prevent from errors in the assessment of commercial petroleum potential of the region.