Study on the Law of Soil Temperature Change Near the Leakage of Buried Gas Pipeline

Distributed optical fiber monitors the leakage of gas pipelines through temperature measurement, but whether the leakage can cause temperature changes at the optical cable has not yet been experimentally verified and mature theory; further analysis and research are needed. Combined with the real gas equation, this paper establishes a numerical model of gas pipeline leakage; and calculates and analyzes the basic working conditions of different leakage apertures, pipeline operating pressures, soil parameters, and different leak outlet locations. The analysis yields: (1) 300 mm away from the pipeline monitoring point, the larger the leakage port (<20 mm), the shorter the response time, the smaller the temperature change at the leakage port, and the faster the temperature change of the optical cable. (2) the same leakage pore size and operating pressure, the closer the monitoring point, the shorter the response time. (3) The greater the leakage pressure, the faster the rate at which the monitoring point detects the temperature change. (4) With the increase of soil thermal conductivity, the faster the optical fiber detects the temperature change. (5) The ambient temperature has almost no effect on the rate at which temperature changes are detected.