某N80新油管早期腐蚀穿孔失效分析  

Analysis on Corrosion Perforation Failure on New N80 Tubing

作　　者：韩燕 巨亚锋[2] 罗有刚[2] 梁万银 赵密锋[3] 付安庆 尹成先 HAN Yan;JU Ya-feng;LUO You-gang;LIANG Wan-yin;ZHAO Mi-feng;FU An-qing;YIN Cheng-xian(State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials,CNPC Tubular Goods Research Institute,Xi'an 710077,China;Petroleum Technology Research Institute of PetroChina,Changqing Oilfield Company,Xi*an 710018,China;Oil and Gas Engineering Research Institute of PetroChina,Tarim Oilfield Company,Korla 841000,China)

机构地区：[1]中国石油集团石油管工程技术研究院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,陕西西安710077 [2]中国石油长庆油田分公司油气工艺研究院,陕西西安710018 [3]中国石油塔里木油田公司油气工程研究院,新疆库尔勒841000

出　　处：《材料保护》2020年第11期160-165,共6页Materials Protection

基　　金：国家科技重大专项(2016ZX05051);中石油重大科技专项(2018E-1809)资助。

摘　　要：针对某N80新油管的早期腐蚀穿孔现象,开展失效原因及机理分析,以为此类失效的预防及控制提供理论依据。基于失效油管的产品标准和失效经过,通过宏观观察、化学成分分析、力学性能测试、金相组织分析、扫描电镜和能谱分析,结合服役工况,综合分析了其早期腐蚀穿孔的失效原因及机理。结果表明:该失效油管的化学成分和力学性能符合相关标准要求,金相组织未见异常。其宏观和微观腐蚀形貌均表明腐蚀与外壁机械损伤形貌吻合,腐蚀产物为氧腐蚀产物。该油管的失效行为是油管外壁局部腐蚀导致的穿孔,失效原因是由于上扣时液压大钳造成的机械损伤与环空污水溶解氧介质相接触,新鲜表面与相邻表面构成电偶腐蚀,发生氧的电化学腐蚀,使得作为阳极的局部位置迅速腐蚀穿孔。建议选用无损伤型液压动力钳,并严格按规定上卸扣,同时加注环空保护液避免外壁腐蚀。For the perforation problem of N80 tubing used in a gas well,the analysis on the failure causes and mechanism was carried out to provide theoretical basis for failure control of these tubing. Based on production standards and failure background of the failed tubing,the cause of perforation was comprehensively analyzed by means of visual inspection, chemical composition analysis, mechanical property test,metallographic structure analysis,scanning electron microscope (SEM),and energy spectrum (EDS) analysis combined with the operation history analysis. Results showed that the chemical composition and mechanical properties of the failed tubing met with relevant standards,and no abnormality was detected in metallographic structure. The macroscopic and microscopic morphology showed that the corrosion was consistent with the morphology of mechanical damage on the outer wall,and the corrosion products were oxygen. Failure behavior of the tubing was local corrosion perforation on the outer wall. Mechanical damage induced by hydraulic tongs clasp on the outer and corrosion media with oxygen in the annulus sewage led to electrochemical corrosion of oxygen between fresh surface and adjacent surface,which resulted into rapid corrosion perforation of anode. It was suggested that non-damaging hydraulic tool should be chosen and the annular protection fluid should be used to avoid external corrosion.

关 键 词：N80油管 腐蚀穿孔 机械损伤 氧腐蚀 

分 类 号：TE973[石油与天然气工程—石油机械设备] TG172[金属学及工艺—金属表面处理]