Research and Application of CCUS Wellbore Integrity Evaluation Technology Across the Full Lifecycle

Driven by the “dual carbon” goals, Carbon Capture, Utilization and Storage (CCUS) technology has emerged as a critical enabler for low-carbon transition in fossil energy utilization. Wellbore integrity, serving as the cornerstone for safeguarding the entire CCUS industrial chain, necessitates evaluation methodologies spanning the complete lifecycle—from geological storage site selection, through CO2 injection for enhanced oil recovery (EOR), to long-term containment. Building upon the technical practices of CNPC Logging Company, this study establishes a multidimensional logging technology framework integrating reservoir classification evaluation, dynamic monitoring, and leakage early warning. It systematically elucidates the principles and field applications of core technologies including pulsed neutron oxygen activation logging, advanced ultrasonic imaging, and distributed fiber optic monitoring. Empirical analyses from representative blocks (e.g., X3 Chang-8 CO2 zone) validate the efficacy of this system in identifying gas channeling in ultra-low permeability reservoirs, detecting casing corrosion, and assessing cement bond integrity. The reservoir classification-guided gas channeling identification method and the multifunctional Combinable Logging Platform for CCUS Evaluation (CCFET) provide innovative solutions for ensuring safe and efficient CCUS operations, offering significant insights for scaling up CCUS deployment in China.