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A Lift-Off-Tolerant Magnetic Flux Leakage Testing Method for Drill Pipes at Wellhead

Lookup NU author(s): Chaoqing Tang



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


To meet the great needs for MFL (magnetic flux leakage) inspection of drill pipes at wellheads, a lift-off-tolerant MFL testing method is proposed and investigated in this paper. Firstly, a Helmholtz coil magnetization method and the whole MFL testing scheme are proposed. Then, based on the magnetic field focusing effect of ferrite cores, a lift-off-tolerant MFL sensor is developed and tested. It shows high sensitivity at a lift-off distance of 5.0 mm. Further, the follow-up high repeatability MFL probing system is designed and manufactured, which was embedded with the developed sensors. It can track the swing movement of drill pipes and allow the pipe ends to pass smoothly. Finally, the developed system is employed in a drilling field for drill pipe inspection. Test results show that the proposed method can fulfill the requirements for drill pipe inspection at wellheads, which is of great importance in drill pipe safety.

Publication metadata

Author(s): Wu JB, Fang H, Li L, Wang J, Huang XM, Kang YH, Sun YH, Tang CQ

Publication type: Article

Publication status: Published

Journal: Sensors

Year: 2017

Volume: 17

Issue: 1

Online publication date: 21/01/2017

Acceptance date: 17/01/2017

Date deposited: 30/03/2017

ISSN (print): 1424-8239

ISSN (electronic): 1424-8220

Publisher: MDPI AG


DOI: 10.3390/s17010201


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