Research on Gas Distribution Pattern in Deep Coal-Bed Based on In-situ Detection

Knowing about the distribution of gas pressure in coal seam is significative to study the flow of coal seam gas, the occurrence and the change of dynamic phenomenon. An in-situ detection is used to detect the in-situ occurrence of gas in No.3 coal seam in Sihe coal mine of Jincheng Anthracite Mining Group in Shanxi province. The distribution of gas pressure around the holes and the change of the content of gas are studied abstractly, which based on the mathematical simulation of the seam gas-seepage. The results show that in-situ detection technique of coal seam gas could shorten the time of from founding the coal to starting to detect, which observably improved the accuracy of testing data, and meanwhile, made up for the deficiency of traditional detection technique in the loss of pressure at earlier stage. It is concluded that the pressure of the initial reservoir gas was about 0.3MPa, from the results of the detection of No.3 coal seam in Sihe coal mine. In order to simulate the distribution of gas pressure surrounding the drilling hole in No.3 coal seam in Sihe coal mine, the mathematical models of the seam gas-seepage were built through COMSOL numerical simulation software. From the results of simulation, the dates on the distribution of gas pressure and the content of gas were obtained.