Abstract: In response to the rapid growth of China’s natural gas peak-shaving demand and the persistent shortfall in the effective working gas volume of underground gas storage (UGS), this paper addresses the problem of storage Capacity Expansion and Deliverability Enhancement in depleted gas reservoir-type UGS. A systematic analysis of technical bottlenecks and development pathways is presented. The study reveals that Chinese UGS facilities are doubly constrained by: complex geological conditions—including structural fracturing, deep burial, and strong reservoir heterogeneity—and multi-cycle injection-production dynamic effects—such as alternating stress damage, near-wellbore salt deposition, secondary water lock, and expansion of the gas-water transition zone. These factors collectively result in low storage capacity utilization. By integrating typical domestic and foreign cases, a technical system centered around “well-pattern optimization–injection-production regulation–edge-water displacement–liquid-drainage capacity expansion” is proposed. Specifically, intensifying the injection-production well pattern can expand the reservoir control range; differential injection and production schemes can balance the displacement efficiency and system stability; coordinated well-pattern adjustment for gas-drive-water can effectively suppress water encroachment; and the exploitation of liquid fluids can release pore space and reduce dissolution losses. Numerical simulations and field practices indicate that the above-mentioned technologies can increase the working gas volume of gas storage. In the future, it is necessary to combine intelligent optimization algorithms with multi-field coupling models to form a full-life-cycle dynamic regulation and control technology, providing theoretical support for the efficient capacity expansion of gas storage in China.