Geochemical Integrity of Wellbore Cements during Geological Hydrogen Storage

Increasing greenhouse gas emissions have put pressureon globaleconomies to adopt strategies for climate-change mitigation. Large-scalegeological hydrogen storage in salt caverns and porous rocks has thepotential to achieve sustainable energy storage, contributing to thedevelopment of a low-carbon economy. During geological storage, hydrogenis injected and extracted through cemented and cased wells. In thiscontext, well integrity and leakage risk must be assessed throughin-depth investigations of the hydrogen-cement-rockphysical and geochemical processes. There are significant scientificknowledge gaps pertaining to hydrogen-cement interactions,where chemical reactions among hydrogen, in situ reservoir fluids,and cement could degrade the well cement and put the integrity ofthe storage system at risk. Results from laboratory batch reactionexperiments concerning the influence of hydrogen on cement samplesunder simulated reservoir conditions of North Sea fields, includingtemperature, pressure, and salinity, provided valuable insights intothe integrity of cement for geological hydrogen storage. This workshows that, under the experimental conditions, hydrogen does not inducegeochemical or structural alterations to the tested wellbore cements,a promising finding for secure hydrogen subsurface storage.