Monitoring of Buried Pipeline using Distributed Fiber Optic Technologies: Combined Acoustic-Temperature-Strain Sensing

This paper presents the development of distributed optical fiber sensing system, which combined acoustic-temperature-strain sensing to enhance the condition monitoring of buried pipeline. The developed optical fiber system was tested using the 140 m long pipe-soil test facility built in the Hawk testing yard. Cement lined steel pipes with the diameter of 100 mm and 500 mm were buried at the depth of 800 mm and optical fiber cables were attached at four different locations around the pipe section. The pipe section was also instrumented with contact microphones to detect the acoustic signal. Various size of leaks were made along the pipe section and monitored using the acoustic signal and temperature sensing. Both acoustic and temperature sensing detected the leak reliably with required accuracy up to distance of 40 km. Using the combination of acoustic and temperature helped confirm the leak and reduce the false positives.