注二氧化碳提高采收率是开展碳捕集、利用和封存 (CCUS) 中的重要环节和三次采油的重要手段。在注入井中开展注气剖面测井, 可以反映注气井层间、层内吸气差异, 揭示注产矛盾, 为堵气调剖提供依据; 井筒完整性的好坏是CCUS中存储阶段中的重要一环, 直接决定埋存效果, 井筒窜漏又会直接影响注气驱油效果; 吸气指数测试可以对地层吸气能力进行评价, 给出地层现阶段合理的注入压力。由于二氧化碳气体在井筒内通常以超临界流体状态存在, 传统测井技术具有一定的局限性, 本文围绕脉冲中子氧活化测井原理和施工工艺开展适应性研究, 结合长庆油田黄3区CCUS区块中注气井应用实例, 阐明脉冲中子氧活化测井在二氧化碳注入井中可以开展吸气剖面刻画、吸气指数测试以及井筒完整性评价, 具备良好的应用效果。

Carbon dioxide injection to improve oil recovery is an important link in carbon capture, utilization, and storage (CCUS) and an important means of tertiary oil recovery. Conducting gas injection profile logging in injection wells can reflect the inter-and intra-layer suction differences in gas injection wells, reveal the contradictions between injection and production, and provide a basis for gas plugging and profile control; The integrity of the wellbore is an important part of the storage stage of CCUS, which directly determines the burial and storage effect, and wellbore leakage directly affects the gas injection and oil displacement effect; The inspiratory index test can evaluate the formation's gas absorption capacity and provide a reasonable injection pressure of the formation at this stage. Since carbon dioxide gas usually exists in a supercritical fluid state in the wellbore, traditional logging techniques have certain limitations. This paper focuses on the adaptability research of pulse neutron oxygen activation logging principle and construction technology, and combined with the application example of gas injection wells in CCUS block of Huang3 District in Changqing Oilfield, it is clarified that the pulse neutron oxygen activation logging can be used to carry out suction profiling, suction index testing and wellbore integrity evaluation in carbon dioxide injection wells, and it has good application effects.