Research on Negative Pressure Distribution Law for Bedding Gas Extraction Borehole

Assumed three forms of drill hole wall methane inflow through the theoretical analysis,the article set up simple mathematical model,obtained negative pressure distribution law for bedding gas extraction borehole,and derived limit length of for bedding gas extraction borehole and performed the demonstration calculation. The article put forward improvement suggestions which combined with the negative pressure distribution law of drilling for bedding gas extraction in view of the traditional extraction methods,described advantages of new extraction method.