Ф73.02mm×5.51mm80S油管腐蚀失效原因分析

Corrosion Reasons of Ф73.02 mm×5.51 mm 80S Tubing

某油井80S油管在井下5个月开始发生腐蚀现象,并且井下深度越大,油管的腐蚀状况越严重。通过现场调查腐蚀环境,宏观观察样品腐蚀特点,并对样品进行化学成分分析和机械性能测试、电镜观察和分析腐蚀产物等,研究了各种腐蚀介质对80S油管的腐蚀行为,并探究了其外表面腐蚀失效的原因。结果表明,该80S油管所用的1Cr钢种无法抵抗高浓度的CO_(2)与Cl^(-)等多元共存的腐蚀环境,同时,井下高温加速该区域的阳极溶解,从而最终因腐蚀速度过快而发生油管早期失效,并提出减缓油管腐蚀失效的建议。

Corrosion occurred five months after the 80S tubing was put into use in an oil well.The deeper the tubing was underground,the more serious the corrosion situation was.By means of field investigation of corrosion environment,macroscopic observation of corrosion characteristics,chemical composition analysis and mechanical property test on the sample,electron microscope observation and analysis of corrosion products,the corrosion behavior of 80S tubing in various corrosive media was studied.The results show that the 1Cr material used in the 80S tubing cannot resist the corrosion environment with high concentration of C0_(2) and Cl^(-),and the high temperature in the well accelerates the anodic dissolution in this area,resulting in early failure due to too fast corrosion rate.Some suggestions are put forward to slow down the corrosion failure of the tubing.