Simultaneous Distributed Acoustic and Temperature Sensing for Robust Leakage Detection in Gas Pipelines

We report a comprehensive study carried out for the robust detection of leakages in gas pipelines based on, simultaneous distributed sensing of acoustics and temperature due to the leakage event. Such signatures corresponding to the leakage event have been simulated using a computational fluid dynamics (CFD) model. Our CFD analysis reveals that low-porosity soil like clay transmit acoustic waves efficiently thereby facilitating ease of detection using distributed acoustic sensing (DAS), while high-porosity soil like sand exhibit stronger thermal conductivity favoring distributed temperature sensing (DTS). Such observations highlight the importance of simultaneous measurements using DAS and DTS for consistent leak detection across diverse soil conditions. The detection of such signatures through a simultaneous DAS/DTS measurement system are then simulated using a unified numerical model of the Rayleigh/Raman scattering in a standard singlemode fiber and the various noise components. Finally, the simulation results are experimentally validated using controlled experiments conducted over a 43 km-long standard telecom-grade single-mode optical fiber with a spatial resolution of 10 m. Further validation was performed on a pressurized buried pipeline testbed under desert soil conditions, confirming the systems effectiveness in detecting controlled leak events under realistic field conditions. These findings clearly demonstrate the advantage of combining DAS and DTS technologies for reliable and consistent leak detection across diverse underground environments.