Corrosion Failure Resason of Oil Well Casing Pipe at an Oil Platform

Macroscopic examination, XRD, SEM, simulated seawater testing and other methods were used to study the corrosion cracking reasons of an offshoe oil well casing pipe. The results show that the reason causing cracking was due to seawater entering the casing annulus which contained air. Near the surface of the sea, the oxygen concentration cell was formed, leading to corrosion of the casing pipe in seawater. With the promotion of Cl-, the corrosion cracking occurred.