Abstract: As an important part of Carbon Capture, Utilization and Storage （CCUS） technology, CO₂ geological storage determines the development potential and direction of CCUS technology, and is an effective means to achieve the dual carbon goal. It is of great significance to identify formation responses generated by CO₂ injection for safe and efficient injection. Among these responses, the escalation in pressure is the main factor constraining the storage capacity and safety, fluid dynamics involving dissolution, migration, and potential precipitation are integral to maintaining formation stability and storage efficiency. In addition, reservoir's injectivity, ensuring seamless CO₂ displacement, and the caprock integrity, which forms the basis for evaluating the project's viability. The formation response characteristics caused by CO₂ injection, such as pressure accumulation, pressure conduction, CO₂-water-rock interaction, mineral dissolution and precipitation, and rock pore structure characteristics, are systematically discussed. The influences of wettability, porosity, permeability, fluid properties, rock strength, cap integrity, surface deformation and fault activation on reservoir permeability and cap safety are summarized. It is acknowledged that prevailing research faces notable challenges, namely the unpredictability of pressure dynamics, an incomplete understanding of chemical reaction kinetics, inefficiencies in injection processes, and deficiencies in the sophistication of monitoring and evaluation frameworks. In the future, it is necessary to further deepen the understanding of the storage mechanism, improving the monitoring and assessment methods of formation response, advancing environmental risk assessment methodologies and refining preventive and control technologies to address potential ecological impacts.

Key words: injection process, pressure change, CO₂-Water-Rock Interaction, porosity and permeability characteristics, injectivity