利用磁屏蔽效应改善钻杆漏磁检测信号信噪比

为了高效率地检测油田钻杆，设计了磁屏蔽器，电磁有限元分析表明，有磁屏蔽器存在时，钻杆漏磁信号将明显集中于缺陷附近，且永磁体元件之间通过空气介质耦合的背景磁通会大大降低。钻杆实物漏磁测试证实了这一分析结果，配有磁屏蔽器的探头可明显提高漏磁信号信噪比，有利于提高缺陷漏磁识别率。

SNR Improvement for Drill Pipe Leakage Flux Testing Signals by Using Magnetic Shielding Effect

Magnetic flux leakage（MFL） technique is generally considered to be an efficient and effective non- destructive testing（NDT） method and has been widely used in the oil field inspection industry for the examination of drill pipe. Electromagnetic finite element analysis shows that pipe magnetic flux leakage signals are centralized near defects obviously when the magnetic shielding exists. At this time, the background magnetic flux between permanent magnet components through the air coupling shall be reduced greatly. Drill pipe magnetic flux leakage testing confirms the analysis results, and the probe with magnetic shielding device can improve SNR of the magnetic flux leakage signals obviously. Thus, it is helpful to improve pipe leakage flux testing sensitivity.