Trend of soil temperature during pipeline leakage of high-pressure natural gas: Experimental and numerical study

Abstract

The key to buried gas pipeline leakage detection using a distributed optical fiber is to detect temperature changes. However, the trend of temperature change caused by natural gas leakage lacks tests and verification. Optical cable laying on site is not standard. In this work, combined with the Peng-Robinson (PR) real gas state equation and fiber Raman scattering principle, the trend of soil temperature around a leakage hole was systematically studied. The simulation results show that the higher the pressure of pipeline, leakage hole and soil porosity, the faster the rate of temperature change is monitored, the greater the temperature change at leakage hole. Temperature change can be clearly detected within 100 mm from the leak hole. On this basis, a field test was conducted for a buried high-pressure gas pipeline leakage. The test used the array of point temperature sensor and fiber to collect the change of soil temperature. The test results show that the soil temperature field at the leakage hole changed the most. The temperature change was detected within 100 mm away from the leakage hole. The test and simulation results are basically consistent.