Helium exploration perspectives in the Pannonian Basin

This review paper synthetizes available data on the helium content of natural gases in the Pannonian Basin ranging from 3 to 15800 ppm. The migration of the helium-rich thermogenic gases occurred mostly during the post-rift inversion of the basin, likely in the last 4-6 million years. Besides the well-known mantle and crustal sources, helium generation and migration have been influenced by Mesozoic coal-bearing strata, which generated not only helium but also large amount of thermogenic gases acting as carrier fluids for helium transporting it to accumulation sites. The numerous occurrences of helium across the basin, in the light of the rapidly growing demand in Europe, highlight the need for systematic helium exploration efforts in certain segments of the Pannonian Basin. This effort should begin with the sampling and analysis of still producing, yet unstudied, gas wells. In addition, many of the non-producing, plugged and abandoned gas wells with high nitrogen content measured in them may represent promising helium exploration targets.