Long-Term Wellbore Integrity in Geological Storage Systems: Implications for CO۲ and Hydrogen Storage

Ensuring long-term wellbore integrity is crucial for the safe and sustainable operation of underground storage systems that involve carbon dioxide (CO۲) and hydrogen (H۲). This review comprehensively examines the key degradation mechanisms affecting casing, cement, elastomers, and legacy infrastructure under chemically reactive and cyclic loading conditions. The study highlights corrosion, hydrogen embrittlement, carbonation, microbial activity, and thermo-mechanical fatigue as dominant failure pathways in CO۲ and H۲ storage environments. It evaluates the suitability of advanced corrosion-resistant alloys, polymer-modified cement systems, and hydrogen-compatible elastomers. Furthermore, state-of-the-art monitoring techniques, such as fiber-optic sensors, ultrasonic imaging, and distributed acoustic sensing, are reviewed in conjunction with predictive modeling approaches, including FEPS analysis, CO۲-PENS, and hydrogen diffusion simulations. Field evidence from Sleipner, Teesside, and Ketzin projects is used to contextualize the risks and validate mitigation strategies. The paper proposes a conceptual integrity framework integrating geomechanics, chemical compatibility, and data-driven diagnostics to address long-term operational challenges. This work aims to support the design of robust wellbore systems and enhance the reliability of subsurface gas storage under evolving thermodynamic and geochemical conditions.

کلیدواژه ها:

Wellbore integrity ، Underground gas storage ، Hydrogen embrittlement ، Cement degradation ، CO۲ sequestration ، Corrosion-resistant materials