Accurate Location Method of Drilling Hole Activities on Oil Pipelines based on Wavelet Packet

摘要

A method of detecting drilling hole activity and locating accurate sources in buried oil pipelines was developed, based on vibration signal propagation and wavelet packet transform (WPT). Experiments were performed to locate man-made damaging sources. Complicated disturbances in the field cause large location errors with the direct cross correlation method. Therefore, WPT is used to decompose the signal into a series of time domain signals, each of which covers specific frequency band information. Packets containing large amounts of energy are focused on, and selected as, feature packets to reconstruct the signal, then cross-correlation analysis is applied. Finally, by comparing the correlation coefficients of the reconstructed signal, the time point corresponding with maximum correlation coefficient is selected as delay time, which determines the location of the drilling site. Results show that the proposed method improves location precision in detection.