Geochemical modeling of H2 storage in a sandstone reservoir: Sensitivity analysis of abiotic H2S and CO2 gas formation
Abstract
Hydrogen storage in geologic reservoirs is a promising technology for storing surplus renewable energy, but the H2 gas quality may be compromised by fluid-rock-gas interactions. Using redox-decoupled, kinetically-controlled, abiotic 0D batch models, this study simulates the 30-year geochemical evolution of a sandstone reservoir (117 °C, 150 bar Ptotal, 98 mol% H2) and quantifies the temporal evolution of gas concentrations (H2, CO2, H2S). The models reveal two concurrent reaction regimes: initial perturbation of the pre-existing carbonate-fluid-gas equilibrium, causing CO2 degassing (∼4.2 mol%) and siderite dissolution, and long-term pyrite reductive dissolution with secondary pyrrhotite precipitation. Leaching of Fe2+ from Fe-chlorite enhances sulfide scavenging via pyrrhotite formation, stabilizing H2S(gas) at 26-28 ppm. Sensitivity analyses (40-140 °C, 5-250 bar Ptotal, 0.001-2.0 vol% pyrite) demonstrate that the reservoir geochemistry is governed by a reaction feedback loop involving: i) sulfide release from reductive pyrite dissolution, ii) aqueous sulfide removal by pyrrhotite precipitation, and iii) secondary Fe2+-mobilization from ferrous minerals. An Fe-mineral buffer sequence (Fe-chlorite → siderite → ankerite) determines the geochemical impact on the reservoir. Siderite alteration notably increases dilution of the H2 storage gas mixture by CO2. Under storage-relevant conditions (T ≤ 120 °C, Ptotal ≥ 50 bar), our batch models indicate H2S(gas) concentrations ranging from 0.5 to 80 ppm at H2(gas) concentrations from 85 to 98 mol%. At temperatures ≤ 80 °C, the mineral reaction kinetics are slow enough to significantly reduce gas contamination, with abiotically-derived concentrations > 97 mol% H2. Our gas estimates are conditional, but stress the importance of non-sulfide Fe-minerals to prevent excessive H2S accumulation.
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BibTeX
@article{hintzen2026geochemical,
title = {{Geochemical modeling of H2 storage in a sandstone reservoir: Sensitivity analysis of abiotic H2S and CO2 gas formation}},
author = {Robin Hintzen and Jeroen Snippe and Tim Tambach and Roland Hellmann and Laurent Truche and Kevins Rhino and Julia van Winden},
journal = {Applied Geochemistry},
year = {2026},
month = oct,
doi = {10.1016/j.apgeochem.2026.107098},
url = {https://brgm.hal.science/hal-05799930v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Geochemical modeling of H2 storage in a sandstone reservoir: Sensitivity analysis of abiotic H2S and CO2 gas formation
AU - Robin Hintzen
AU - Jeroen Snippe
AU - Tim Tambach
AU - Roland Hellmann
AU - Laurent Truche
AU - Kevins Rhino
AU - Julia van Winden
PY - 2026
DA - 2026/10/02
JO - Applied Geochemistry
DO - 10.1016/j.apgeochem.2026.107098
UR - https://brgm.hal.science/hal-05799930v1
AB - Hydrogen storage in geologic reservoirs is a promising technology for storing surplus renewable energy, but the H2 gas quality may be compromised by fluid-rock-gas interactions. Using redox-decoupled, kinetically-controlled, abiotic 0D batch models, this study simulates the 30-year geochemical evolution of a sandstone reservoir (117 °C, 150 bar Ptotal, 98 mol% H2) and quantifies the temporal evolution of gas concentrations (H2, CO2, H2S). The models reveal two concurrent reaction regimes: initial perturbation of the pre-existing carbonate-fluid-gas equilibrium, causing CO2 degassing (∼4.2 mol%) and siderite dissolution, and long-term pyrite reductive dissolution with secondary pyrrhotite precipitation. Leaching of Fe2+ from Fe-chlorite enhances sulfide scavenging via pyrrhotite formation, stabilizing H2S(gas) at 26-28 ppm. Sensitivity analyses (40-140 °C, 5-250 bar Ptotal, 0.001-2.0 vol% pyrite) demonstrate that the reservoir geochemistry is governed by a reaction feedback loop involving: i) sulfide release from reductive pyrite dissolution, ii) aqueous sulfide removal by pyrrhotite precipitation, and iii) secondary Fe2+-mobilization from ferrous minerals. An Fe-mineral buffer sequence (Fe-chlorite → siderite → ankerite) determines the geochemical impact on the reservoir. Siderite alteration notably increases dilution of the H2 storage gas mixture by CO2. Under storage-relevant conditions (T ≤ 120 °C, Ptotal ≥ 50 bar), our batch models indicate H2S(gas) concentrations ranging from 0.5 to 80 ppm at H2(gas) concentrations from 85 to 98 mol%. At temperatures ≤ 80 °C, the mineral reaction kinetics are slow enough to significantly reduce gas contamination, with abiotically-derived concentrations > 97 mol% H2. Our gas estimates are conditional, but stress the importance of non-sulfide Fe-minerals to prevent excessive H2S accumulation.
SN - 0883-2927
ER -