Study on Leakage Detection and Location Technology for Oil Transportation Pipelines Based on Infrasonic Wave

Pipeline leakage occurs frequently due to inevitable aging, pipeline erosion, abrasion and sabotage. Study on the technology of leakage detection and its location has become an emerging topic. The technology of leakage detection and its location for oil pipelines based on infrasonic wave is that detecting and locating leakage by inspecting the infrasonic wave which generated by the leakage fluids turbulent jetting on the wall of pipeline. Analysis to the low frequency acoustic signal which generated by leakage indicates that the features of leaking signals in frequency domain manifests within 10Hz. precisely, it shows spectral power changes took place in 0.4 Hz and 2 other characteristic frequency point. Therefore, the authors choose three infrasonic wave frequencies as test characteristic. It is 0.4Hz, 3.8 Hz and 7.2Hz respectively. It will send abnormal data and global positioning system (GPS) time to center monitor machine. When find out mutations of two power spectrum of characteristic frequency, and its energy order ratio changes immediately. The center monitor machine calculates start-time and data length of capture anomalous signals from the other end stations, and then calls the data from the end stations. According to the GPS time from the stations which have generated the abnormal data, the monitored length of pipeline and propagation speed of leak signal then joint the two ends data based neural network model for further leakage diagnoses. Meanwhile, the leakage points can be located according to the GPS time lag of anomalous signals from the two stations and the velocity of infrasonic wave.