Detection methods and anti-corrosion measures for oil casing

First, detection methods for oil casing

1. Ultrasonic detection: When ultrasonic waves are propagated in the material being tested, the acoustic characteristics of the material and the changes in the internal structure have a certain impact on the propagation of ultrasonic waves. By detecting the degree and situation of the impact of ultrasonic waves, the changes in the function and structure of the material can be understood.

2. X-ray detection: X-ray detection uses the difference in the amount of radiation transmitted between the normal part and the defect to form the discrimination of the blackness on the film.

3. Penetrant detection: Penetrant detection uses the capillary action of the liquid to penetrate the open defect on the surface of the solid material, and then absorbs the penetrated penetrant to the surface through the developer to show the existence of the defect. Penetrant detection is suitable for various metal and ceramic workpieces, and the time from penetration operation to defect appearance is relatively short, usually about half an hour. It can detect surface fatigue, stress corrosion, and welding cracks, and can directly measure the size of the cracks.

4. Magnetic particle testing: Magnetic particle testing uses magnetic leakage at defects to absorb magnetic particles and form magnetic traces to provide defect visualization. It can detect surface and sub-surface defects. The nature of the defects is easy to distinguish. Paint and electroplating surfaces will not affect the detection vividness.

Second, anti-corrosion measures for oil casing

1. First, ensure that water quality meets standards and strictly test and manage water quality. Implement separate injection of cleaning and pollution, strengthen the cleaning of the main water pipeline, ensure that the water quality in the station and at the bottom of the well meets the standard, and reduce the introduction of corrosion sources into the annular space;

2. For newly commissioned water injection wells, adopt annular protection fluid mainly for sterilization, and form a system to add it regularly;

3. In view of the accelerated effect of mechanical abrasion on the corrosion of oil casing, it is recommended to add a rubber ring to the tubing coupling or a centralizer to the part with serious well deviation to avoid the tubing from scratching the casing and contacting the casing on one side during the operation and water injection process;

4. In view of the serious corrosion of bacteria under the scale and the slow growth and killing of SRB at high temperature, high-temperature water or water vapor of 100 degrees Celsius can be regularly injected into the annulus to kill the SRB under the scale;

5. Before the corrosion in the casing of the water injection well is effectively controlled, it is not recommended to promote the use of cathodic protection and coated casing.