塔里木油田某井经历了2 d的鲜酸酸化和10 d的残酸返排过程, 管柱起出后发现油管内壁发生了严重腐蚀。对酸化油管进行理化性能检测, 并结合实际工况, 对油管内壁腐蚀原因进行了综合分析。结果表明: 该油管的化学成分和金相组织均符合API Spec 5CT-2005的相关技术要求。导致油管内壁发生严重腐蚀的因素主要有三个: 一是鲜酸和残酸在管柱中停留时间过长;二是井下温度较高,加快了腐蚀进程; 三是酸化过程中缓蚀剂可能没有发挥有效的作用。建议尽量缩短酸化作业时间, 在井筒温度较高的情况下, 应筛选合适的耐高温酸化缓蚀剂, 减少酸液对油管的腐蚀。

After undergoing two-day fresh acid acidizing and ten-day spent acid flow-back, the oil tube inner wall of a gas wall in Tarim oilfield severely corroded. A comprehensive failure analysis was conducted based on physical testing, chemical analysis, as well as field investigation. The results show that chemical composition and metallurgical structure of the oil tube met the requirement of API Spec 5CT-2005. There were three main reasons contributing to the corrosion failure of the oil tube. Firstly, the fresh acid and spent acid stagnated in tube exceeded the expected operating time; secondly, the high temperature of downhole significantly enhanced the corrosion process; thirdly, inhibitor might not work sufficiently during acidizing process. It is suggested to shorten the operating time of acidizing process, and choose the optimal acidizing inhibitor which could be used at high or extremely high temperatures to reduce the corrosion of oil tube because of acid solution.