Localised corrosion failure of an L245N pipeline in a CO₂–O₂–Cl⁻ environment

ABSTRACT

Multicomponent thermal fluid flooding has become a widely used and very effective heavy-oil recovery technology, but the harsh CO₂–O₂–Cl⁻ environment can lead to serious corrosion perforation failure of the pipeline. Therefore, the influence of O₂ content and main controlling factors on corrosion perforation were investigated through a weight-loss experiment, corrosion defect test, characterization and grey correlation method. The results showed that, with the increase in O₂ content, the general corrosion rate and localized corrosion rate increased. The uneven protection performance of the product after the addition of O₂ was found to be the key cause of localized corrosion. In addition, the synergistic effect of O₂–Cl⁻ promoted the lateral and longitudinal expansion of pits. The results of the grey correlation showed that the temperature (30–120 °C) had a greater impact on localized corrosion compared with the content of O₂ (0–0.045 MPa) and Cl⁻ (0–16,000 mg/L).

KEYWORDS:

• Pipeline failure
• corrosion perforation
• synergistic effect of O₂–Cl⁻
• O₂ content
• L245N steel
• main controlling factors

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 52174062] and the Natural Science Foundation of Sichuan [grant number 2023NSFSC0420].