Failure Analysis of Corrosion and Perforation of Oil Pipe of a Water Injection Well

The tubing of a water injection well was corroded and perforated. The reasons for the failure of oil pipe corrosion perforation were analyzed by means of macroscopic observation, chemical composition analysis, metallographic examination, energy spectrum analysis, X-ray diffraction analysis, mechanical property test and bacterial culture test. The results show that the existence of sulfate reducing bacteria and saprophytic bacteria reduced SO₄^2- to H₂S in the solution. The existence of H₂S led to the corrosion of the tubing wall, which resulted in the corrosion and perforation of the tubing. The corrosion type of oil pipe was microbial corrosion under scale.