Objective and Methods  Driven by the goal of carbon neutrality, geological CO₂ storage has become a critical national priority. Compared to traditional sedimentary basin reservoirs (e.g., saline aquifers, depleted oil/gas reservoirs, and unmineable coal seams), in situ CO₂ mineralization in basalt offers significant advantages, including widespread distribution, substantial storage potential, and low leakage risk, by converting CO₂ into stable carbonates through mineral carbonation reactions. Its engineering feasibility has been validated and demonstrated by CarbFix and Wallula pilot projects. Buried volcanoes within sedimentary basins are also promising targets for in situ mineral carbonation, owing to their abundant basaltic rocks, extensive distribution, and large storage capacity. However, a systematic evaluation of their feasibility, safety, and economic viability has been lacking. This study assesses the technical and economic potential of buried volcanoes based on their global distribution, material composition, reservoir properties, reservoir-seal assemblage, as well as evaluations of storage capacity, environmental risks, and costs related to in situ mineralization.

Results and Conclusions  (1) The buried volcanoes are globally widespread and possess enormous storage potential. They are characterized by highly reactive ferromagnesian mineral assemblages that enhance carbonation efficiency, along with well-developed pore networks that form high-quality reservoirs. Their internal complex architecture can provide natural reservoir-seal assembles, confirming theoretical and technical feasibility. The inherent safety of mineral trapping, combined with multiple containment barriers at the basin scale, ensures minimal leakage risk. In situ mineralization is relatively low-cost, and the reuse of existing infrastructure and potential co-storage opportunities in petroliferous basins can further reduce economic expenditures, highlighting its economic attractiveness. Thus, buried volcanic structures represent a highly suitable target for in situ CO₂ mineralization, outperforming typical basalt formations in terms of technical feasibility, storage security, and economic viability. (2) However, several technical challenges remain, including an incomplete understanding of CO₂-fluid-rock reaction mechanisms and difficulties in characterizing internal volcano architectures. Future efforts should focus on coupled experimental and numerical studies of multi-physical processes in CO₂-fluid-rock systems, as well as refined characterization of volcano architectures in basins. (3) Based on geological conditions, this study identifies the Tarim Basin (western terrestrial region) and the Pearl River Mouth Basin (eastern offshore area) as priority zones for implementing CO₂ storage in buried volcanoes in China. These recommendations aim to provide reliable target support and geological foundations for achieving carbon neutrality goals.