Petroleum casing pipe thread detection methods and standards

Detection Methods and Procedures

- Appearance Inspection

Use visual inspection or a magnifying glass to check for cracks, rust, burrs, and other defects on the thread surface.

- Dimensional Inspection

Utilize measuring tools such as calipers and micrometers to detect key dimensions like the major diameter, minor diameter, and thread pitch.

- Tightness Test

Employ special tools such as plug gauges or ring gauges to assess the tightness of the threads, ensuring a secure connection.

- Torque Detection

During the connection process, use a torque wrench to verify that the connection torque meets the specified requirements.

Testing Standards and Specifications

- API Standard

The threads of oil casing pipes should comply with relevant standards set by the American Petroleum Institute (API), such as API SPEC 5CT.

- ISO Standard

The International Organization for Standardization (ISO) has established standards for oil casing threads, such as ISO 11960.

- National Standards

Various countries have their own national standards, such as China's GB/T 9253.

- Corporate Standards

Some large petroleum companies develop their own corporate standards to guide production and testing.

Common Problems and Solutions

- Thread Damage

Problem: Thread damage may occur due to improper handling during processing or transportation.

Solution: Enhance protection during processing and transportation; repair or replace damaged threads.

- Size Out of Tolerance

Problem: Thread size deviations may result from insufficient accuracy of processing equipment or improper operation.

Solution: Improve the accuracy of processing equipment, strengthen operator training, and enhance dimensional inspection.

- Insufficient Tightness

Problem: Insufficient tightness may occur due to inadequate thread machining accuracy or improper operation during the connection process.

Solution: Improve processing accuracy, strengthen monitoring and adjustment during the connection process, and use high-quality sealing materials.

- Torque Issues

Problem: The torque may be too high or too low due to improper operation or equipment failure during the connection process.

Solution: Provide enhanced operator training, conduct regular maintenance and calibration of torque wrenches, and use high-quality joining materials.