Gas extraction concentration control and its influencing factors analyze

Considering the fact that current concentration of gas extraction is too low, the researchers obtained the formula of gas emission in borehole drilling through the occurrence and theoretical analysis that gas migration regularity of coal bed. Based on the assumption of the relevant knowledge, fluid mechanics, established the theoretical calculation model of leakage calculating, the researchers also found that the gas pressure, permeability coefficient of coal bed was relatively stable, gas flow-volume was largely unchanged during extraction process in a certain period of time, and air leakage was directly proportional to both the negative pressure of extraction and the three times of the height of the leakage gaps. However, it was inversely proportional to the sealing length of the drilling, which provides a design reference for gas extraction sealing study. © 2011 IEEE.