Based On The Radial Flow Theory Evaluation Can Be Smoked Performance Coal Seam

With China's coal mining strength and mining depth of coal mine and increased, gas outburst mines increase gradually. How to take effective measures to realize safe high-efficient exploitation, become in the important task before mining workers. Gas pressure is appraisal of coal and gas outburst mines, but also the landmark parameters division outburst mines the main basis. In the new mining, outburst mines to a new level must test gas pressure, this is the prevention of coal and gas outburst regulation ", "coal and gas outburst appraisal regulations regulations and requirements of normal industries such as work. Gas pressure reflects not only the size, and finally the gas pressure in pressure test process also reveals the dynamic process of gas flow.Taking Horner approximation and coal seam gas flow theory as hypothesis foundation, systematically expounds the coalbed gas drilling radial flow law of gas flow theory. Combined with radial drilling surrounding gas pressure and pressure falloff curves, studies the changes of coal seam gas attenuation coefficient permeability and drilling the change rule of coal seam, reflecting the difficulty of the drainage. The research result can show that in practical applications only long enough in the determination of stabilizing determination results circumstance, can make the calculated results and the practical results more fully close. By using time series analysis method, establishes the pressure falloff curve model, according to the mathematical theory knowledge and the flow law of coalbed gas analysis, combining drilling gas pressure falloff curves and get a calculation, a new method of permeability coefficient coal seam. In this paper the permeability coefficient calculation method of coal seam new practical investigation application, the result shows the method calculating permeability coefficient and drilling coal seam with attenuation coefficient speediness, reliability, accuracy, and the characteristics of coal seam can better reflect the drainage sex, and reached the expected gas drainage effect.