某井S135钢级钻杆腐蚀失效原因  

Reasons for Corrosion Failure of S135 Steel Grade Drill Pipe in a Certain Well

作　　者：陈猛[1] 欧阳志英[1] 余世杰[1] CHEN Meng;OUYANG Zhiying;YU Shijie(Shanghai Hilong Oil Tubular Goods Research Institute>Shanghai 200949,China)

机构地区：[1]上海海隆石油管材研究所,上海200949

出　　处：《机械工程材料》2021年第3期93-97,共5页Materials For Mechanical Engineering

基　　金：上海市优秀技术带头人计划资助项目(19XD1430400)。

摘　　要：某井S135钢级钻杆在钻进约2 395 m时发生腐蚀失效。采用宏观形貌、断口形貌观察,显微组织分析,化学成分、硬度、腐蚀产物成分测试对其失效原因进行了分析。结果表明:该钻杆的失效方式为腐蚀疲劳失效,钻杆内壁的氧含量偏高及内壁加厚过渡带区域存在应力集中,导致加厚过渡带区域发生严重点蚀,点蚀坑底部萌生疲劳裂纹并扩展,最终钻杆失效;建议使用内壁带防腐涂层的钻杆,并在钻井液中添加缓蚀剂,降低溶解氧对内壁的腐蚀作用,同时优化井深结构,减缓内壁加厚过渡带区域的应力集中。The S135 steel grade drill pipe of a certain well suffered corrosion failure when the drilling distance was about 2 395 m.The fracture reason was analyzed by macromorphology and fracture morphology observation,microstructure analysis,and chemical composition,hardness,and corrosion product composition tests.The results show that the failure mode of the drill pipe was corrosion fatigue failure.The inner wall of the drill pipe had high oxygen content and stress concentration in the thickened transition zone of inner wall,resulting in severe pitting corrosion in the thickened transition zone.Fatigue cracks were initiated in the bottom of the pits and propagated,fainally leading to the failure of the drill pipe.It was recommended to use the drill pipe with anticorrosive coating of inner wall,add corrosion inhibitor to the drilling fluid to reduce the corrosion effect of dissolved oxygen on the inner wall,and optimize the well depth structure to reduce stress concentration.

关 键 词：S135钢级钻杆 加厚过渡带区域 点蚀 氧含量 应力集中 疲劳裂纹 

分 类 号：TH142.2[一般工业技术—材料科学与工程]