【摘要】 深水气藏开发是保障中国能源警戒线和建设能源强国的必要途径之一，但深水高含CO₂气井井下管柱长期在高温高压、强腐蚀环境中服役，容易发生腐蚀失效，导致管柱强度发生衰减，影响环空带压临界值预测精度，增大了环空带压管控难度。为此，通过自研自制的高温高压釜腐蚀实验装置开展深水高含CO₂气井井下管柱腐蚀规律研究，分别考虑均匀腐蚀和点蚀对管柱强度的衰减作用，建立管柱剩余强度计算模型，提出考虑不同腐蚀类型的深水井环空带压临界值计算方法。结果表明：均匀腐蚀作用下环空带压临界值的初始值大，但随年限降低幅度较大，最大极限压力由51.88 MPa降至42.40 MPa;点蚀作用下环空带压临界值的初始值小，随年限降低幅度较小，最大极限压力值由22.30 MPa降至21.55 MPa;考虑均匀腐蚀作用下的环空带压临界值在服役前期主要受技术套管抗内压强度影响，随着腐蚀的进行，在服役后期，主要受油管的抗外挤强度影响；考虑点蚀作用下的环空带压临界值主要在整个服役期间主要受油管的抗外挤强度影响。研究成果可为深水高含CO₂气井环空带压管控提供参考。更多还原

【Abstract】 The development of deep-water gas reservoirs is one of the necessary ways to ensure China’s energy warning line and build an energy powerhouse. However, the downhole pipes of deep-water high CO₂ gas wells have been in service for a long time in high temperature, high pressure, and strong corrosive environments, which are prone to corrosion failure, leading to a decline in pipe strength, affecting the accuracy of predicting the critical value of annular pressure, and increasing the difficulty of controlling annular pressure. To this end, a self-developed high-temperature and high-pressure kettle corrosion experimental device was used to study the corrosion law of downhole pipe columns in deep water high CO₂ gas wells. The attenuation effects of uniform corrosion and pitting corrosion on the strength of the pipe columns were considered, and a residual strength calculation model for the pipe columns was established. A calculation method for the critical value of annular pressure in deep water wells considering different types of corrosion was proposed. The research results indicate that the initial value of the critical value of annular pressure under uniform corrosion is large, but it decreases significantly with age, and the maximum ultimate pressure decreases from 51.88 MPa to 42.40 MPa. The initial value of the critical value of annular pressure under pitting corrosion is small, and the decrease in magnitude with the annual limit is small. The maximum limit pressure value decreases from 22.30 MPa to 21.55 MPa. Considering that the critical value of annular belt pressure under uniform corrosion is mainly affected by the internal pressure strength of the technical casing in the early stage of service, and with the progress of corrosion, it is mainly affected by the extrusion resistance of the tubing in the late stage of service. Considering the critical value of annular belt pressure under pitting corrosion, it is mainly affected by the anti-extrusion strength of the tubing during the whole service period. The research results can provide a reference for the control of annular pressure in deep-water high CO₂ gas wells.更多还原