Corrosion Failure Analysis of an Oil Tube Used in a Western Oilfield

Chemical composition analysis, metallurgical microscopy, scanning electron microscopy, energy dispersive analysis of X-ray and electrochemical method were used to investigate the corrosion failure of oil tubing. Combined the field parameters, operation history and lab analysis results, it is concluded that the severe pitting corrosion occurred on the external surface of tnbing was mainly due to the failure of tube packer caused the entrance of acid (including fresh acid and residual acid) into the annulus between tubing and casing. The reason for the corrosion degree difference between tube body and coupling is the difference in the chemical composition, metallurgical structure, and electrochemical corrosion property between the tube boby and the coupling.