Investigation Of The Magnetic Flux Leakage Detection Technology For Drill Pipe Body Transversal Defects And Wall Thickness Loss

Drill pipe to be subjected to in the course of pulling, twisting, bending，alternating stress,serious drilling lfuid dissolved C02，H2S corrosion medium will drill pipe corrosion，corrosion of drill pipe can easily stresslapse under the action of the puncture and ruptureaccident. Magnetic flux leakage inspection of drill pipe body，is the most effective method forthe prevention of drill pipe failure, reduce drilling accidents.Based on the problems of the production site, in-depth analysis of research carried out onthe drill pipe magnetic flux leakage detection system identiifed by comparison of the effect ofthe AC and DC magnetization types of magnetizing current, and the design of the drill pipemagnetization unit to ensure that the magnetizationto the axis of the drill pipe body. Thedefect signal acquisition, the mechanism of ampliifcation and digital processing done a lot ofresearch, careful analysis of the sensitivity of the sensor coil sensor and the Hall element andapplicability, design-speciifc probe of the leakage magnetic ifeld detection. Ampliifedaccording to the actual design of the circuit, the iflter circuit and the A/D conversion, will becollected, ampliifcation, and ifltering process is integrated in a board. Re-establish the tubebody detection database developed pipe detection software, real-time display, storage,playback and printing capabilities of the waveform. Especially instrument calibrationautomatic calibration program development greatly reduce the time of instrument calibrationonly need to walk a standard pipe, the echo height of8pens all adjusted to80%of the ofilscale, the waveform detection repetition rate, and can be classiifcation of drill pipe, to meetthe requirements of the oil drill pipe body detection. And classification of drill pipe, guidingthe drilling crews classification used to reduce drilling accidents.