Acoustic sensing techniques have demonstrated to be promising methods for leak detection. A major challenge lies in the multi modes and dispersion nature in acoustic signals propagating along pipelines, which may cause inaccurate estimation of wave velocity and time delay. To find a best solution for precise leak identification considering a specific application scenario, a field test is conducted on a gas pipeline in service with strong background noise. Various factors affecting the in-situ measurements are investigated, including the ambient noise, the existence of elbow, weld seam, anticorrosive paint or polyethylene coating. The dispersive curve of the test pipeline is theoretically simulated and experimentally measured. Two methods based on discrete wavelet transform and time–frequency spectrum are then employed for leak locating. The positioning accuracy of the two methods are compared and discussed with regards to the influence factors in field testing.

声学传感技术已被证明是一种很有前途的泄漏检测方法。一个主要挑战在于沿管道传播的声信号的多模式和色散性质，这可能导致波速和时间延迟的不准确估计。为了结合特定的应用场景找到精确泄漏识别的最佳解决方案，我们对在役的具有强背景噪声的天然气管道进行了现场测试。调查了影响现场测量的各种因素，包括环境噪声、弯头的存在、焊缝、防腐漆或聚乙烯涂层。对试验管道的色散曲线进行了理论模拟和实验测量。然后采用基于离散小波变换和时频频谱的两种方法进行泄漏定位。