API oil casing is a steel pipe used to support the walls of oil and gas wells, ensuring the proper operation of the well during drilling and after completion.
Hydrostatic Pressure Test of Casing Pipe
The hydrostatic pressure test is a crucial part of the production process for steel pipes. Its purpose is to verify the pipe's anti-leakage performance under standard test pressure and specified duration. Similar to radiographic and ultrasonic inspections, it is an essential method for assessing the overall quality of steel pipes.
In simple terms, this test involves filling the pipe with water and testing its ability to maintain a specified pressure without leaking or breaking. The procedure includes three main steps: flushing, pressure testing, and water control.
API 5CT Standard for Hydrostatic Pressure Test
- Test Pressure Value: The hydrostatic pressure test value for coupling and threaded pipe is determined by the lowest value among the hydrostatic test pressure of the flat end pipe, the maximum hydrostatic pressure test pressure of the coupling, and the internal pressure leakage resistance. The maximum standard pressure is 69 MPa, with calculated values rounded to the nearest 0.5 MPa.
- Calibration: According to API requirements, the hydrostatic test pressure measuring device must be calibrated within four months before each use.
- Special Requirements: If the customer has special requirements, a higher test pressure can be applied.
- Leakage Criteria: Any leakage detected during the hydrostatic pressure test is a basis for rejection of the pipe.
- Exceptions: Unless otherwise agreed between the purchaser and the manufacturer, hydrostatic pressure testing is not required for coupling blanks, coupling materials, nearby materials, or Q125 steel pup joints.
This comprehensive testing ensures the reliability and safety of API oil casing pipes, critical for the successful operation of oil and gas wells.
