Failure analysis on the oxygen corrosion of the perforated screens used in a gas injection huff and puff well

The perforated screens of a gas injection huff and puff well broke down in an oilfield in western China. The physical and chemical properties of the failure-perforated screens met the requirements of relevant technical protocols. The injected gas was nitrogen produced by the membrane nitrogen method, which contains approximately 5% O-2. Therefore, a substantial amount of O-2 entered the well during the gas injection, and greatly promoteed the cathodic process of the electrochemical corrosion. High salinity formation water, especially with large amounts of Cl-, further accelerated the corrosion. The significant oxygen corrosion under the well finally led to the failure of the perforated screen.