Next Article in Journal
Ubiquitous Emergency Medical Service System Based on Wireless Biosensors, Traffic Information, and Wireless Communication Technologies: Development and Evaluation
Previous Article in Journal
Efficient Wideband Spectrum Sensing with Maximal Spectral Efficiency for LEO Mobile Satellite Systems
Article Menu
Issue 1 (January) cover image

Export Article

Open AccessArticle
Sensors 2017, 17(1), 201;

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

School of Manufacturing Science and Engineering, Sichuan University, Chengdu 610065, China
School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
School of Electrical and Electronic Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
Author to whom correspondence should be addressed.
Academic Editor: Vittorio M. N. Passaro
Received: 17 December 2016 / Revised: 14 January 2017 / Accepted: 17 January 2017 / Published: 21 January 2017
(This article belongs to the Section Physical Sensors)
Full-Text   |   PDF [7109 KB, uploaded 21 January 2017]   |  


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. View Full-Text
Keywords: MFL (magnetic flux leakage); drill pipe; lift-off distance; magnetic field focusing MFL (magnetic flux leakage); drill pipe; lift-off distance; magnetic field focusing

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Supplementary material


Share & Cite This Article

MDPI and ACS Style

Wu, J.; Fang, H.; Li, L.; Wang, J.; Huang, X.; Kang, Y.; Sun, Y.; Tang, C. A Lift-Off-Tolerant Magnetic Flux Leakage Testing Method for Drill Pipes at Wellhead. Sensors 2017, 17, 201.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Sensors EISSN 1424-8220 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top