Temporary underground storage of molecular hydrogen (H2) in depleted oil and gas reservoirs has recently attracted increasing research interest as it can support chemical industry demands and peak-shaving in the energy supply grid. Experimental parameters related to abiotic chemical reactions, microbial metabolism, and transport mechanisms of molecular hydrogen under elevated pressure conditions in such reservoirs are of potential relevance to these applications but have rarely been studied. As far as abiotic chemical reactions are concerned, since mineral coatings of hematite are a common feature in conventional reservoirs, a thorough understanding of the reactivity of the hematite-H2 reaction system is of utmost importance. In addition, potential microbial growth in the pore space of reservoirs may affect the preset gas composition as well as petrophysical properties.
In this context, RWTH-Aachen University is coordinating the “H2_ReacT2” project, a follow up cooperation together with the Bundesanstalt für Geologie und Rohstoffe (BGR) and the Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum (GFZ). The overall objective is to gain a comprehensive understanding of relevant abiotic and biotic redox reactions, associated changes of petrophysical properties and molecular mass transfer within potential underground storage formations.
In this session, we will present analytical data of novel experimental approaches to study (1) the kinetics of the H2-H2O-hematite reaction system at low temperatures and elevated H2 pressures, and (2) the effects of microbial metabolism of H2 and overburden pressure on storage and transport properties of a typical reservoir rock, the Bentheimer sandstone.