Research On Lightweight Magnetizer And Vehicle-borne System For Drill Pipe Magnetic Leakage Detection

As an important part of oil drilling,drill pipe can transmit pressure and torque to drill bit.In the whole working process,the drill pipe not only bears the alternating load and contact stress,but also can receive the corrosion medium corrosion in the mud,which is easy to make the drill pipe produces the flaw,causes the significant accident and brings the inestimable economic loss.Therefore,nondestructive testing of drill pipe is of great significance.In the Magnetic flux leakage(MFL)nondestructive testing technology,magnetization is the key to realize detection,which is of great significance to the generation of magnetic flux leakage and the resolution of magnetic field signals.At the same time it also has an important influence on the performance analysis of detection signal and the mechanical design of detection device.Different magnetization methods are required for different occasions.This paper aims to study the lightweight direction of magnetization technology,so that the magnetizer can meet the magnetization requirements and reduce the quality at the same time.This paper introduces the structure characteristics and processing technology of drill pipe,discusses the advantages and disadvantages of each excitation method from the perspective of traditional excitation methods,and proposes a lightweight magnetization method based on electromagnetic and permanent magnet combined excitation.The relative magnetic circuit was designed,and the parameters affecting magnetization in the magnetic circuit structure were simulated and optimized by using some methods,such as ANSYS finite element,so as to obtain the lightweight parameters of the magnetizer meeting the magnetization requirements.The final optimized magnetized structure was physically processed,and the magnetic sensor was used to verify the inspection capability of the drill pipe defect,so that the requirements fot detecting defects such as through hole and inner blind hole of drill pipe are satisfied.Compared with the permanent magnet magnetizer,the disassembly suction of the magnetizer is small,and the magnetization intensity can be adjusted,which is convenient for operation.Combined with the above analysis results and engineering requirements,the semi-weekly composite magnetizer is applied to the vehicle-mounted drill pipe detection system.In this system,the flaw detector is portable flaw detector,which requires light weight,small volume and compact structure.According to the system inspection requirements,the detection method of in-situ rotation of drill pipe and forward detection of vehicle was proposed.The magnetic flux leakage detection system for drill pipe with multiple specifications was designed,and the high-speed automatic detection process was developed.The magnetic flux leakage detection system of vehicle-mounted drill pipe mainly includes mechanical system,control system and signal system.This system integrates the advantages of fixed flaw detection system and portable flaw detector,and has the advantages of high detection efficiency,accurate detection results,easy to realize high-speed automation,and at the same time it can realize detection anytime and anywhere,which is has a broad application prospect.