气井N80Q油管腐蚀失效分析  

Corrosion Failure Analysis of N80Q Tubing in Gas Well

作　　者：师伟 孙龙飞 赵光强 张康 祁炜 徐正华 SHI Wei;SUN Longfei;ZHAO Guangqiang;ZHANG Kang;QI Wei;XU Zhenghua(Key Laboratory of Petroleum Tubular Goods and Equipment Quality Safety for State Market Regulation,CNPC Tubular Goods Research Institute,xi′an,Shaanxi 710077,China;Petrochina Coalbed Methane Company Co.,Ltd.,Beijing 100028,China)

机构地区：[1]中国石油集团工程材料研究院有限公司,国家市场监管重点实验室(石油管及装备质量安全),陕西西安710077 [2]中石油煤层气有限责任公司,北京100028

出　　处：《石油管材与仪器》2023年第5期55-58,共4页Petroleum Tubular Goods & Instruments

摘　　要：某气井在采气生产过程中油管的内表面发生了腐蚀失效。为了确定该油管腐蚀失效的原因,对其内表面的腐蚀形貌、油管材料的化学成分和金相组织及腐蚀产物进行了分析,并分析了油管接箍内的流体流态。结果表明,该腐蚀油管外的内表面呈现沟槽状腐蚀特征,局部存在溃疡状腐蚀坑。腐蚀油管材料的化学成分和金相组织均符合API Spec 5CT标准的要求,腐蚀产物主要物质为FeCO_(3),另外腐蚀产物含有少量的Fe_(3)O_(4)和SiO_(2)。该气井油管内流动的流体含有CO_(2),另外由于油管内表面的腐蚀产物主要为FeCO_(3),因而油管内表面发生了CO_(2)腐蚀。在油管外螺纹和接箍连接处的内径突变部位发生了冲刷腐蚀,并使外螺纹部位出现了穿透油管管壁的腐蚀孔洞。建议在含有CO_(2)的天然气的气井中使用内涂层油管。A gas well has a corrosion failure on the inner surface of the tubing during gas production.In order to determine the cause of the corrosion failure of the tubing,the corrosion morphology,chemical composition,metallographic structure,and corrosion products were analyzed.The results indicate that the outer surface of the failed oil pipe is slightly corroded,the inner wall is characterized by groove corrosion,and there are ulcer corrosion pits in some areas.The chemical composition and metallographic structure of the failed tubing meet the standard requirements of API Spec 5CT,and the main corrosion product is FeCO_(3),containing a small amount of Fe_(3)O_(4)and SiO_(2).The fluid flowing in the tubing of the gas well contains CO_(2),and because the corrosion product on the inner surface of the oil pipe is mainly FeCO_(3),CO_(2)corrosion occurs on the inner surface of the tubing.Erosion corrosion occurs at the sudden change in the inner wall of the external thread and coupling connection of the tubing,and the corrosion holes that penetrates the tubing wall appears in the external thread.It is recommended to use inner coated tubing in gas wells containing corrosive gas and with severe erosion.

关 键 词：油管落井 螺纹滑脱 二氧化碳腐蚀 穿孔 

分 类 号：TE931[石油与天然气工程—石油机械设备]