The SFMC jury has decided to award the 2026 Haüy-Lacroix Prize to Robin Hintzen.
Robin Hintzen’s PhF, titled “Abiotic Reactivity of Minerals at High H2 Concentrations: Experimentation and Modeling Applied to Deep Aquifers,” was completed at the Institute of Earth Sciences (University of Grenoble-Alpes) under the supervision of Laurent Truche and Roland Hellmann, in collaboration with Shell Global Solutions International B.V.
The aim of this study was to gain a better understanding of fluid-rock-gas interactions in a reducing environment with a high partial pressure of H₂, particularly in underground H₂ storage reservoirs. Using autoclave experiments and a suite of analytical methods to characterize altered minerals, the aqueous phase, and the gas phase, the reactivity between minerals and dissolved H₂ was studied under conditions representative of storage (30–150°C, pH < 200 bar).
This research has highlighted the crucial role of reductive dissolution of pyrite in reservoir rocks and cap rocks. On the one hand, pyrite is transformed into pyrrhotite through a local fluid-assisted mineral-mineral replacement mechanism, with the production of H₂S. On the other hand, pyrite indirectly triggers reactions involving iron-bearing minerals and carbonates. In its absence, no significant reaction was observed, even after ten months of exposure to 120 °C and 100 bar of H₂. Kinetic laws governing the reductive dissolution of pyrite were then established as functions of temperature, partial pressure of H₂, and pH. These were then used to model the geochemical evolution of an H₂ storage system over 30 years in a depleted natural gas reservoir. A sensitivity analysis of gaseous H₂S production revealed a mechanism for controlling sulfide concentrations, based on the dissolution of ferrous minerals (chlorite, siderite, ankerite) and the precipitation of pyrrhotite. This mechanism governs long-term abiotic geochemistry in underground H₂ storage reservoirs.
Beyond H₂ storage, these results are also relevant to other H₂-rich environments, such as nuclear waste storage sites or natural systems that produce H₂.
