Abstract

Hydrogen will play a pivotal role in the green transition as a primary natural source and secondary carrier of energy. This seminar will therefore cover i) the development of exploration methods for natural “gold” H₂ and ii) the assessment of long-term safety effects of H₂ storage in depleted gas fields. 

Soil gas measurements have been carried out over a natural gas reservoir (CH₄) with abundant H₂ likely originating from radiolysis in the granitoid basement. Elevated signals along faults show that despite H₂ enrichment in the underlying gas field, fault-related vertical migration to the surface occurs. Furthermore, the molecular and stable isotope composition of soil gas, as well as soil composition and microbiology, have been investigated. A deep H₂ signal is likely overlain by an additional, microbial signal in “H₂-prone” soil zones, potentially resulting in the misinterpretation of a deep geogenic source. Additionally, high mud gas H₂ concentrations have been detected during exploratory drilling at another site. Multiple parameters confirm its drilling-induced (i.e., artificial) generation. This highlights that great caution and a multi-disciplinary approach are necessary to correctly evaluate H₂ exploration data.

The Austrian Lehen Field is the first successful H₂ storage facility in a porous reservoir and therefore a great opportunity to study long-term safety of H₂ injection. Potential gas-caprock-brine interactions have been assessed by gas exposure experiments at reservoir conditions. Mineralogical, hydrochemical, and high-resolution petrographical data suggest that H₂ reactions with caprock and brine are negligible and therefore do not constitute a major storage risk.

Biography

David Misch holds a doctoral degree from Montanuniversitaet Leoben, where he also obtained his habilitation in geology. He worked as an invited postdoctoral researcher at RWTH Aachen University and was awarded the Walther E. Petraschek and Hans Höfer von Heimhalt prizes of the Austrian Academy of Sciences and the Austrian Geological Society, respectively, for his early career research in sedimentology. He was appointed Professor of Energy Geosciences at Montanuniversitaet Leoben in 2023 and currently heads the Chair of Energy Geosciences as well as the Department of Applied Geosciences and Geophysics. Furthermore, he is partnering expert at Geos4 Potsdam, a leading consultancy in the geoenergy sector.