Acoustic method of high-pressure natural gas pipelines leakage detection: Numerical and applications

Leak detection is one of the most important issues in natural gas pipelines operation, major accidents can result from pipe gas leaks in pipelines that transport high-pressure gases. Natural gas pipeline leakage can cause huge economic losses and affect public health. Currently, pipeline leak detection relies on the semi-empirical formula based on the traditional basis. However, such methods have obvious limitations. It is impossible to predict the new process in a forward-looking way, which leads to a sharp increase in cost. The infrasonic wave method offers the possibility of continuous acoustic monitoring of pipelines and remote detection of leaks. In this work, the time-frequency signal of pipe leakage acoustic wave was studied by using the method of “acoustic - pipe and acoustic - pressure” multi-physical field coupling. Finally, the acoustic leakage monitoring method was applied to the field pipeline. The results show that: 1) natural gas pipeline leakage is a kind of broadband noise. With the increase of frequency, the energy tends to oscillate and decay; 2) the acoustic wave propagates from the leakage hole, and the amplitude decreases rapidly. 3) the leakage acoustic energy is mainly concentrated below 20 Hz, and the mean sound pressure increases with the increase of internal pressure and leakage diameter; 4) ultra-low frequency sound pressure level (SPL) is of great significance to the detection of natural gas pipeline leakage by the acoustic method. The field experiment demonstrates that this method can improve the detection ability of small leakage. Hence, the proposed method provides a new approach for the detection of pipeline leakage in technology popularization and engineering applications. • The acoustic characteristics in high pressure natural gas pipeline are analyzed by multi-physics coupled. • The laws of pressure perturbations changing with many factors can be obtained. • Infrasound detection technology based on Möhring acoustic analogy theory is applied to field pipeline. • The method reduces the response time and improves the positioning accuracy.