松辽盆地火石岭组深层火山岩储层受超低渗透率与极致密性制约，经济高效开发面临严峻挑战，同时也为CCUS背景下的CO₂利用与封存提供了潜在目标储层。研究针对此难题探索并验证了基于超临界CO₂（SC-CO₂）协同地层水的水岩作用改造方法。通过构建SC-CO₂饱和溶蚀反应实验，结合X射线衍射（XRD）矿物定量分析、场发射扫描电镜（FE-SEM）微观形貌表征及岩石力学性能测试，系统研究了SC-CO₂协同地层水对储层的改造效果。实验结果表明：SC-CO₂优先溶蚀斜长石和方解石等矿物，导致黏土矿物含量显著降低，并形成微小裂缝和孔道。基于CT扫描构建的三维数字岩心模型进一步揭示，经SC-CO₂处理后，储层孔隙结构得到显著改善：配位数（CN）大于3的优势渗流通道占比提升约11%，喉道半径大于6 μm的孔隙体积增加16.5%以上，模拟渗透率与实际气测渗透率变化趋势一致，同比增幅均超过90%。同时，岩石力学测试显示：SC-CO₂作用后岩样抗压强度下降19.6%，弹性模量降低13.2%，泊松比增加8.7%，结合扫描电子显微镜（SEM）观察证实其通过力学弱化可有效诱发次生裂缝网络。研究表明：SC-CO₂凭借其纳米级分子扩散能力与零界面张力特性，能够有效进入微纳级孔隙，并与孔隙束缚水形成碳酸，通过水岩反应深度溶蚀储层内部，有效弥补了传统酸液难以触及微纳米级孔隙的局限。该方法为深层火山岩储层的经济高效开发及CCUS技术中的CO₂协同埋存与增渗改造提供了新的理论依据与技术路径。

The deep volcanic reservoirs of the Huoshiling Formation in the Songliao Basin face severe challenges for economically efficient development due to ultra-low permeability and extreme compactness, while also presenting potential target reservoirs for CO₂ utilization and storage under CCUS scenarios. To address this challenge, this study explored and verified a water-rock interaction modification method based on supercritical carbon dioxide (SC-CO₂) synergized with formation water. Through SC-CO₂ saturation dissolution reaction experiments, combined with X-ray diffraction (XRD) mineral quantitative analysis, field emission scanning electron microscopy (FE-SEM) microstructural characterization, and rock mechanical property testing, the modification effects of SC-CO₂ synergized with formation water on the reservoir were systematically investigated. The experimental results showed that SC-CO₂ preferentially dissolved minerals such as plagioclase and calcite, leading to a significant reduction in clay mineral content and the formation of microscopic fractures and pore throats. Three-dimensional digital core models constructed from CT scans further revealed that SC-CO₂ treatment significantly improved reservoir pore structure: the proportion of dominant flow channels with coordination numbers (CN) >3 increased by approximately 11%, while pore volumes with throat radii >6 μm expanded by over 16.5%. The trends of simulated permeability were consistent with the changes in actual gas permeability measurements, both showing year-on-year increases exceeding 90%. Meanwhile, rock mechanical tests indicated that after SC-CO₂ treatment, the compressive strength of rock samples decreased by 19.6%, the elastic modulus decreased by 13.2%, and the Poisson’s ratio increased by 8.7%. Combined with scanning electron microscopy (SEM) observations, these results confirmed that mechanical weakening effectively induced a secondary fracture network. The study indicated that SC-CO₂, owing to its nanoscale molecular diffusion capability and zero interfacial tension, could effectively penetrate micro- and nano-scale pores and react with pore-bound water to form carbonates. Through water-rock interactions, it deeply dissolved the interior of the reservoir, effectively overcoming the limitation of traditional acid fluids in accessing micro- and nano-scale pores. This method provides new theoretical foundations and technical pathways for the cost-effective development of deep volcanic reservoirs and for CO₂ co-storage and enhanced recovery modification in CCUS technology.