Seismic exploration technology plays an increasingly prominent supporting role in gas storage construction. To extend the technical support of oil and gas exploration and development to deep underground energy storage business, a complete set of fine interpretation technology system covering the entire chain of "oil and gas exploration and development — deep underground energy storage application" has been established. Taking the depleted gas reservoir gas storage in the complex mountainous area of the Sichuan Basin as the research object, this paper addresses the geological exploration difficulties including dual complexity of surface and underground, well-developed fracture system, shallow burial depth and thin thickness of reservoirs. Starting from the actual needs of gas storage construction, the study focuses on the fine characterization technology of underground gas storage cavities, fully integrating abundant basic data such as geological features, drilling, logging and VSP.The research results show that: Firstly, the fine characterization technology of complex structural traps based on structural pattern analysis can accurately characterize the spatial distribution of gas storage layers, providing a guarantee for "injectability"; Secondly, the fine characterization technology of small fractures based on multi-attribute analysis can objectively evaluate the sealing performance of major faults and the connectivity of micro-fractures. Combined with the fine prediction technology of thin reservoirs to clarify the distribution range of reservoirs, it effectively supports "storage capacity"; Thirdly, the optimized well pattern deployment and while-drilling tracking design technology can improve gas storage efficiency and reduce construction costs and risks, while the geological steering technology can real-time guide the precise target entry of highly deviated sections and horizontal sections of injection-production wells, ultimately achieving the core goal of "injectability and producibility".This series of fine interpretation technologies has effectively reduced the multi-solution nature of exploration results for complex depleted gas storages, providing important technical support and decision-making basis for the scientific site selection, rational design and efficient operation of gas storages. It also holds reference and guiding significance for seismic exploration research of similar gas storages at home and abroad.