| CBM has been widely used in various industries as a new energy.China is a big country of coal,the resource of CBM are abundant,second only to the United States and Canada,situated third in the world.But the situation of high reservior low permeability has been restricting the development of Chinese CBM industry.The mining method of CBM has been research in widespread.In order to obtain the law of desorption migration and temperature influence on permeability when the microwave heating,Exploration when the porosity reaches a certain threshold,the medium does not penetrate into the permeable percolation transition.The paper adopt the method of experimental research,main use of self-made multi-field desorption temperature permeability tester combined with CT scanning system.Development of microwave heating equipment coupled with it.Test were analyzed from many angles,for instance,the microscopic and macroscopic physical chemistry.According to experiments we found:Temperature is an important factor in changing the characteristics of the coal seam permeability,through the software of Origin obtained the variation of desorption amount with time and permeability with temperature under different stress,Coal samples obtained fracture porosity distribution at different temperatures,binary view and high-precision CT scan channel Figure.According to the experimental analysis of the results obtained the following conclusions :(1)Three factors affect the efficiency of the microwave heating: tube pitch,antenna length,copper wire turns;(2)At the same temperature,with the pore pressure greater,the amount of desorption more much and the speed is faster,the temperature promote desorption amount increase but not linearly;(3)Under the same effective stress,permeability with increasing temperature decreases after the first increase,the temperature threshold is approximately 80 ℃;(4)Through CT scan found the temperature range of coal occurs percolation transition. |
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