Calculation of Coal Seam Permeability and Gas Pressure Based on Borehole Gas Emission Law Back Analysis Model

In view of the focal problem that it is difficult to direct measure the coal seam permeability and gas pressure in coal mine safety production, the back analysis model of coal seam permeability and gas pressure has been established which based on the theory of coal seam gas radial flow, the model has the advantage of no need the direct measure of gas pressure, just need borehole gas emission law can back analysis to ascertain the coal seam permeability and gas pressure, and carried out in practice in coal seam of E8-10 in Pingdingshan Coal Mine Group. Application results show that: the measured value of coal seam permeability and gas pressure has little impact on borehole diameter, but has significant impact on time effect. The data of the linear regression analysis of figure q(-1) -Int which was chosen after 5 days can reduce errors. The back analysis model measurements of borehole gas emission law are accurate and reliable compared with the direct measured values, it provides a new way for measurement of coal seam permeability and gas pressure.