Step-by-step pressurization dense-phase CO2 injection method and injection system

The invention relates to the technical field of ground engineering CCUS, in particular to a step-by-step pressurization dense-phase CO2 injection method and system, and the injection method comprises the following steps: a multi-element CO2 gas source is initially in a dense-phase state with the pressure of 10 MPa and the temperature of 15 DEG C, enters an injection allocation station, keeps the dense-phase state after primary pressurization, exchanges cold, and performs secondary pressurization; and finally, CO2 is conveyed to the injection well in a dense-phase state with the pressure being 25 MPa. The method has the advantages that the cost is low, the conveying distance is long, the requirement for the purity of CO2 is low, and the requirement for high formation pressure can be met. 本发明涉及地面工程CCUS技术领域，具体涉及一种逐级增压密相CO2注入方法和注入系统，所述注入方法包括如下步骤：多元CO2气源初始为压力10MPa和温度15℃的密相状态，进入配注站，一次增压后保持密相状态，再换冷、进行二次增压，最终实现CO2以压力为25MPa的密相状态输送至注入井，本发明具有成本低、输送距离远、对CO2的纯度要求低、可满足高地层压力需求的优点。