Technical Insights into the Compatibility of Salt-Saturated Cement for Underground Storage in Salt Caverns

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Abstract The need for a sustainable and decarbonized energy system has led to a renewed interest in Underground Hydrogen Storage (UHS). These caverns, formed by solution mining of underground salt deposits, offer large storage volumes and high structural integrity. Furthermore, salt caverns exhibit containment properties, with their impermeable salt formations ensuring long-term storage without significant degradation of the hydrogen. This paper investigates the compatibility of salt-saturated cement for Underground Hydrogen Storage in salt caverns. The primary aim is to scrutinize how hydrogen interacts with cement in this unique environment, with implications for the safety and efficiency of hydrogen storage in salt caverns. Therefore, it is important to investigate the interactions between the cement-salt slurry and hydrogen gas, including potential chemical reactions or degradation processes that may occur over time. This information is crucial for designing a storage system that maintains its integrity and performance throughout the storage duration. This abstract discusses the results of aging for 28 days at 100 bar 50°C of one real composition of salt-saturated cement already used in oil and gas wells. The investigation into the compatibility of salt-saturated cement with hydrogen has shown encouraging preliminary results. Mechanical testing indicated only marginal reductions in compressive strength, well within acceptable limits for underground storage structures. Chemical analyses revealed no significant alterations in the cement's composition, suggesting good chemical stability. Observations from real-time aging tests reinforce the material's resilience over prolonged exposure to hydrogen. While these findings are promising, further analyses and long-term studies are warranted to establish definitive conclusions. In summary, the study points to the potential viability of salt-saturated cement for hydrogen storage. However, further analyses are essential to solidify these initial observations and comprehensively understand the material's behavior in salt caverns over time. This paper significantly adds to the current body of knowledge by focusing on the specific challenges posed by salt-saturated environments in hydrogen storage. The detailed exploration of salt-saturated cement compatibility with hydrogen contributes novel insights not widely available in existing literature. This knowledge is pivotal for advancing the understanding and practical implementation of salt caverns for hydrogen storage, marking a distinctive and valuable contribution to the field.