An oil and gas pipeline pre-warning system based on Φ-OTDR

Based on phase-sensitive optical time domain reflectometer (Φ-OTDR), an oil and gas pipeline pre-warning system is demonstrated and applied to monitor products pipeline laying along an optical cable. Theoretically, the longest monitor distance can be as long as the coherent length of light source through connecting repeater optical amplifiers, which can amplify not only pulse light but also Rayleigh scattering light. An appropriate algorithm derived from support vector machine (SVM) is developed to identify and classify different vibration signals along pipeline, including artificial digging, mechanical excavation and vehicles crossing. Field test in Gangzao pipeline shows that the pre-warning system can detect artificial digging within 5m, mechanical excavation and vehicles crossing within 50m.