Genetics of hydrocarbons of natural gas accumulations, discovered in Hungary

Abstract

The author gives an overview about the processes of gas generation, migration and accumulation, moreover about bacterial and thermogenic methane, carbon isotope ratios of which are different. Carbon isotope ratio data of methane in the discovered gas accumulations indicate that gas fields in shallow depths (<1000 m) contain mainly bacterial methane. It can be established that the frequency of the carbon isotope ratio data indicating the presence of the thermogenic methane is already great in depth interval of 1000 to 1500 m, which indicates the vertical migration of gases. The carbon isotope ratio data of ethane and propane indicate that these gas components were generated mainly by oil–generating type of kerogen. According to the vitrinite refelectance equivalent values calculated by carbon isotope ratio difference between ethane and propane can be established that their primary migration took place when the neogene source rocks reached the depths of greater than 3000 m.