Anticorrosion technology of oil tube casing
The anticorrosion process of oil tube casing is a comprehensive process designed to ensure long-term stable operation of casing in harsh underground environment. The following are the main contents of he oil tube casing anticorrosion process from many aspects:
Water quality management
Water quality standards: First of all, it is necessary to ensure that the water quality in the injection well is up to standards to reduce the introduction of corrosion sources due to water quality problems. This includes strengthening water quality testing and management, implementing decontamination separate injection, and strengthening the cleaning of the main water pipeline to ensure that the water quality in the station and at the bottom of the well is up to standard.
Annulus protection fluid: For the injection Wells that have been put into operation, the annulus protection fluid based on sterilization is injected regularly to inhibit bacterial growth and reduce bacterial corrosion. This practice should be institutionalized to ensure regular dosing.
High temperature sterilization: In view of the serious corrosion of bacteria under the scale, and the characteristics of slow growth and easy killing of sulfate reducing bacteria (SRB) at high temperature, high temperature water or water vapor can be regularly injected into the annular cavity at 100 degrees Celsius to kill the SRB under the scale, thereby reducing bacterial corrosion.
Physical protection
Rubber ring and centralizer: Due to the accelerated effect of mechanical abrasion on oil tube casing corrosion, it is recommended to install a rubber ring on the tubing coupling or install a centralizer in the heavily inclined part of the well. This can effectively avoid tubing scratching casing during operation and water injection, and avoid prolonged contact between tubing and casing side, thereby reducing frictional corrosion.
Surface treatment and material selection
Surface treatment: Appropriate treatment of the oil tube casing surface, such as sandblasting, cleaning, etc., to improve the adhesion and anti-corrosion effect of the coating.
Material selection: Choose materials with good corrosion resistance to make oil tube casing, such as stainless steel. Although the cost may be higher, it can effectively extend the service life of the casing.
