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OCTG pipe, drill pipe, corrosion, shedding

Company News

OCTG pipe, drill pipe, corrosion, shedding
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Shedding And Corrosion of Inner Coating of Drill Pipe

Date:2024-11-13View:171Tags:OCTG pipe, drill pipe, corrosion, shedding

Drill pipe is a steel pipe with threads at the tail end, which is used to connect the surface equipment of the drilling rig and the drilling and grinding equipment or bottom hole device at the bottom of the well. It is an OCTG pipe, which is used to transport drilling mud to the drill bit and raise, lower or rotate the bottom hole device together with the drill bit.

Drill pipe internal coating is a coating treatment performed inside the drill pipe. Its main function is to prevent rust, corrosion, reduce friction, and increase wear resistance. The coating can not only increase the service life of the drill pipe, but also improve the exploration efficiency and the success rate of drilling.

 

The main reasons for the shedding and corrosion of the drill pipe internal coating include the following aspects:

1. Chloride ion damage in salt water slurry: When the drill pipe is operating in salt water slurry, chloride ions will destroy the coating structure and penetrate the coating, catalyze and accelerate the corrosion of dissolved oxygen on the drill pipe substrate, resulting in coating shedding and pipe corrosion.

2. Erosion corrosion in high temperature and high flow rate environment: In a high temperature and high flow rate multiphase flow environment, the drill pipe internal coating is susceptible to erosion corrosion. Experiments show that in an environment containing sand or water-carrying sand, the impedance of the coating in the low-frequency zone is severely reduced and the coating surface is damaged and ineffective.

3. Ultraviolet aging: Ultraviolet rays play a decisive role in the aging of the coating. Long-term ultraviolet irradiation can easily lead to molecular chain breakage, resulting in coating powdering.

4. Reasons for the peeling of mechanical paint surface: Including factors such as poor polishing process, incomplete curing of the paint film, erosion by pollutants, and poor bonding between the original paint on the substrate and the water-based paint.

 

Prevention and solution measures:

1. Choose suitable coating materials: Choose suitable coating materials for different working environments. For example, in a salt water slurry environment, a coating material resistant to chloride ion erosion should be used.

2. Control environmental factors: In a high temperature and high flow rate environment, try to avoid an environment containing sand or water-carrying sand to reduce the impact of erosion corrosion.

3. Strengthen coating protection: In areas with strong ultraviolet radiation, take appropriate shading measures to prevent long-term aging of the coating by ultraviolet rays.

4. Optimize the grinding and curing process: Ensure that the grinding process is meticulous, the paint film is completely cured, avoid erosion by pollutants, and enhance the bonding force between the substrate and the coating.

 

Summary

The reasons for the rapid corrosion of the coating on the drill pipe include chloride ion damage, erosion corrosion, ultraviolet aging, etc. Reasonable prevention and solution measures can effectively extend the service life of the coating on the drill pipe and reduce the occurrence of shedding and corrosion.