Underwater natural gas pipeline leakage detection based on interferometric fiber optic sensor in experiment-scale

A distributed optical fiber sensor of underwater gas transmission pipeline leak detector is demonstrated based on spectrum analysis of hybrid interferometer OTDR system. The feasibility of separately locating underwater pipe leaky source and phase signal demodulation scheme were theoretically analyzed. The system is capable of detecting simulated gas pipeline leakage acoustic signal. In underwater waveguide laboratory, the interferometer was used to localize leaky source. The water flow velocity varies from 2 m/s to 4 m/s. The ambient noise interference produced by flow current was discussed. The wavelet transform was performed to improve null frequency capture ability. The localization scheme is tested by the partial experiment data.