西部某油田修复油管螺纹处断裂的原因  

Fracture Causes of Repaired Oil Tubing Thread Used in a Western Oilfield

作　　者：王磊[1] 李岩[2] 龙岩 白真权 WANG Lei;LI Yan;LONG Yan;BAI Zhenquan(State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Eguipment Materials,CNPC Tubular Goods Research Institute,Xi'an 710077,China;Tarim Oil Field,Korla 841000,China)

机构地区：[1]中国石油集团工程材料研究院有限公司石油管材及装备材料服役行为与结构安全国家重点实验室,西安710077 [2]塔里木油田,库尔勒841000

出　　处：《腐蚀与防护》2022年第8期103-107,114,共6页Corrosion & Protection

基　　金：国家自然基金青年基金(51804336);陕西省自然科学基金(2019JM-132)。

摘　　要：采用化学成分分析、力学性能分析、金相检查、扫描电子显微镜观察等手段对西部某油田修复油管螺纹处断裂失效进行了分析。结果表明:井下修复油管管体螺纹发生断裂的主要原因是垢下腐蚀与氯化物应力腐蚀开裂;螺纹牙底外表面附着黑色物质引发垢下腐蚀,Cl^(-)通过缝隙进入金属基体,在拉应力作用下,发生氯化物应力腐蚀开裂,最终造成油管在螺纹处发生断裂。Chemical composition analysis, mechanical property analysis, metallographic exmianation and scanning electron microscopy were used to investigate the fracture failure of repaired oil tubing thread. The results show that the fracture of repaired oil tubing thread at downhole was mainly due to under-deposit corrosion and chloride stress corrosion cracking. The black material covering on the outer surface of thread roots caused under-deposit corrosion. And chloride ions entered into the metal matrix through gaps, chloride stress corrosion cracking occurred under the tensile stress condition, finally resulting in the fracture of repaired tubing at threads.

关 键 词：修复油管 螺纹 应力腐蚀开裂 裂纹扩展 失效分析 

分 类 号：TG172[金属学及工艺—金属表面处理]