Advances in Underground Gas Storage: A Review of Current Practices and Future Prospects

Underground gas storage (UGS) plays a vital role in ensuring energy security and supporting the transition to a low-carbon energy future by enabling the large-scale storage of methane-rich natural gas (NG), carbon dioxide (CO 2 ), and hydrogen (H 2 ). However, the development and operation of UGS systems face complex technical, operational, and geological challenges across different storage environments. This review provides a comprehensive analysis of UGS technologies, focusing on their historical development, current status, and future prospects. The study examines the evolution of UGS applications, from traditional NG storage to the emerging roles of CO 2 and H 2 storage, highlighting shifting priorities in a decarbonizing energy landscape. A detailed evaluation of drilling and completion technologies is presented for various geological settings, including depleted gas reservoirs, salt caverns, and aquifers. The feasibility and performance of these formations for UGS are analyzed, considering repurposing strategies and the specific behaviors of NG, CO 2 , and H 2 under subsurface conditions. Furthermore, this review compares UGS methods through the lens of trapping mechanisms. It also identifies the key technical challenges of well integrity, monitoring, and cyclic operations, and explores the use of simulations and intelligent models for predicting subsurface properties. A cost-benefit analysis of different UGS types is provided to support decision-making for future projects. The future outlook for UGS within a low-emissions energy system identifies research gaps and opportunities to guide further technological advancements.