A Review of Hydrogen–Cement Interactions for Underground Hydrogen Storage

Underground hydrogen storage (UHS) is a promising solution for large-scale and long-duration energy storage, but its safe deployment critically depends on maintaining well integrity. Among the well components, the cement sheath represents a key barrier against hydrogen leakage. This study reviews and synthesizes existing experimental and numerical research on hydrogen–cement interactions, focusing on permeability evolution, mechanical performance, and leakage risk. The evidence indicates that static hydrogen exposure has minimal adverse effects on well-cured Class G cement and may even enhance microstructural density through continued hydration and pore refinement. In contrast, operational factors—particularly cyclic pressure loading and premature hydrogen contact during cement setting—are identified as the primary causes of permeability increase and mechanical degradation. The review further highlights that inconsistent findings in the literature are largely attributable to insufficient consideration of cement pore-scale heterogeneity and the lack of image-based analyses.