Isotopic composition of the products of the mud volcanoes activity in the South-Caspian Basin in connection with petroleum potential of the deeply burried sediments

of petroleum potentialSummary.Currently the most effective way to find hydrocarbons is their prospecting in deeply buried sediments of the operated oil-producing provinces that, in its turn, is related with definite engineer and financial risks.So, the mud volcanoes of the South-Caspian Basin (SCB) can play a role of the natural deep wells and carry value information regarding the processes occurring at great depths.The paper summarized the results of the previous and new studies of the isotopic composition of products of activity (rocks-ejects, gas, oil, water) of the mud volcanoes in the SCB with purpose to forecast the petroleum potential and phase state of HC at the depths inaccessible for drilling and minimize the economic and technological risks of expensive deep wells drilling.It is shown that the position of petroleum charges of mud volcanoes and fields in the section corresponds to the generally accepted vertical zoning of oil-and-gas generation and has a single genetic source.The increase of rocks thickness is observed from onshore towards the central deep part of the SCB and the maturity of oil and gas increases as well accompanying by the change of phase state of the HC from oil to oil-gas and gas-condensate ones.Only gas-condensate accumulations are forecasted in the deep part of the SCB.The lower limit of their generation temperature is approximately assessed as 300 о С, and corresponded to the depth range of about 8 to 16 km.