What other tests are needed for finished drill pipes to leave the warehouse?
The production of a drill pipe requires many process steps. After the drill pipe is made into a finished product, further testing is required. The magnetic flux leakage testing method described below: the drill pipe is a thin-walled pipe and bears the effects of axial force, bending moment, centrifugal force, torsional force and dynamic load during the drilling process. The working conditions are extremely harsh. Especially in deep wells and inclined wells, small defects in drill pipes may lead to downhole drilling tool accidents. With the continuous development of drilling technology, in order to improve the penetration rate, the use of downhole power drilling tools has increased, the drill string speed has improved, and the requirements for the quality of drill pipe have become higher and higher.
I. Current situation of drill pipe flaw detection technology and characteristics of magnetic flux leakage detection technology
At present, the ultrasonic and magnetic particle inspection commonly used in oil fields can only detect the thread of drill pipe, but not the pipe body. The inspection of the pipe body depends on the inspection staff to observe whether the outer wall of the pipe body has puncture and severe trauma (groove, welding scar, erosion pit, etc.). For wall thickness detection, a single-point thickness gauge is used. A total of 12 points are taken to measure the thickness in the circumferential direction of 1.5m from the joints at both ends and the three parts in the middle of the pipe body. The above detection method can not meet the requirements of the drill pipe body flaw detection, and it is easy to produce missed detection.
Magnetic flux leakage testing technology is a newly developed non-destructive testing technology in recent years. The principle is the same as that of magnetic particle testing. It can not only conduct a comprehensive testing of drill pipe, but also obtain intuitive quantitative testing results by using electronic technology. It detects correctly, fast, especially suitable for large quantities of drill pipe detection work.
The working principle of the 2. magnetic flux leakage detection technology device and the factors affecting the detection accuracy
The magnetic flux leakage flaw detector system can complete the internal and external transverse defect detection, pipe wall thickness detection and steel grade comparison and identification. The system adopts the working mode of probe fixing and drill pipe advancing, and uses the high-energy magnetic field generated by the fixed magnetization coil in front of the probe to magnetize the drill pipe to saturation or near saturation.
If the drill pipe if there is a defect or wall thickness loss, the magnetic field leakage, the probe through the period can detect the magnetic field changes, and through the/D conversion to digital signals, the computer processing into intuitive graphics.