Numerical Analysis of Magnetic Flux Leakage of Transverse Defects of Sucker Rod

Abstract

Abstract Sucker rods are required to operate in a very aggressive environment in the oil well industry. The combined effect of significant mechanical forces and a corrosive environment lead to frequent failures during operation. Furthermore, the detection of the defects of a sucker rod is a difficult, urgent problem to be solved in the oil industry. A solution to this situation would be quite helpful for oil field management as well as in regulating the safety management system of the sucker rod. In this paper, a nondestructive testing model of transverse defect, which is the complex crack of the sucker rod, was established using magnetic flux leakage (MFL) technique and a finite element simulation model for transverse defect was achieved using ANSYS software. Firstly, the model of single-coil magnetization and double-coil magnetization were discussed; the results demonstrated the superior performance of double-coil magnetization in comparison with single-coil magnetization. Secondly, two-dimensional MFL modeling was performed and the influence of magnetization and defect size on MFL testing were analyzed. Finally, a three-dimensional MFL model was proposed, and then the magnetic induction intensity of different liftoff values was analyzed for enhancing the detection reliability. The results showed that the MFL technique can be used to detect transverse defects in a sucker rod.