Anti-corrosion measures for oil well casing:
1. Prioritize water quality compliance through rigorous testing and management. Implement separate injection for clean and produced water, and strengthen the cleaning of main water pipelines to ensure water quality meets standards at both the station and the well bottom, thereby minimizing the introduction of corrosive agents into the annulus.
2. For newly commissioned water injection wells, utilize an annular protective fluid-primarily containing bactericides-and establish a protocol for regular application.
3. Given that mechanical abrasion accelerates casing corrosion, it is recommended to install rubber rings on tubing couplings or centralizers in sections with significant wellbore deviation; this prevents the tubing from scraping or making direct contact with the casing during operations and injection.
4. To address severe under-deposit bacterial corrosion-and considering the growth and elimination dynamics of sulfate-reducing bacteria (SRB) at high temperatures-periodically inject high-temperature water (100°C) or steam into the annulus to kill SRB colonies beneath the deposits.
5. The widespread adoption of cathodic protection and coated casing is not recommended until internal casing corrosion in water injection wells has been effectively brought under control.
