FAILURE ANALYSIS OF S135 DRILL PIPE

Failure analysis was conducted on S135 drill pipe by means of electron probe microanalyzer (EPM),and scanning electron microscopy (SEM). It is indicated that the Cl- ion introduces pitting,and thus corrosion fatigue was induced under the drilling stress,which leading to the perforating failure of drill pipe. Based on the investigation results,appropriate anti-corrosion measures were proposed.