Research on the Method for Drill Pipe Thread Inspection
Failure of the drill pipe thread is always a very serious problem which may result in serious accidents and rework during the drilling of oil wells. Rupture crack of the drill pipe thread may result in great economic and labour losses, so they need to be inspected periodically. As the drill pipe thread is not a smooth surface and is in the end area of drill pipes, it is very difficult to be inspected by traditional Non-destructive testing (NDT) methods. According to the experiment results and the requirement of the working conditions in the field, a local MFL inspection method, which is the most adaptive inspection method, is determined. Laboratory testing and field experience show that this inspection method can detect the crack as small as 0.6mm (depth) in the thread root and thus reduces the risks of drilling failure. This local MFL inspection method can inspect flaws of the drill pipe thread that occur in practice exactly and quickly, and it has very wide application perspectives.
Seung-Seok Lee, Joon Hyun Lee, Ik Keun Park, Sung-Jin Song, Man Yong Choi
J. F. Ding, Y. H. Kang, X. J. Wu, "Research on the Method for Drill Pipe Thread Inspection", Key Engineering Materials, Vols. 321-323, pp. 472-475, 2006