Study on Adsorption of Coal Bed Methane in Huale Exploration Zone of Zhina Coalfield in West Guizhou

In order to find out the coal bed methane adsorption features of the main mining seams in the Huale Exploration Zone and the main geological factors affected to the adsorption,the isothermal adsorption experiment results of the collected coal samples were applied to the study on the logging information of two coal bed methane wells in Huale Exploration Zone.The study results showed that the adsorption value of the main mining seam in Huale Exploration zone was high,the dry no ash base Langes volume was ranging from 17.69~21.38 m3/t and the average was 19.46 m3/t.The site measured saturation of the coal reservoir all was less than 100% generally,the distribution was 75.04%~105.55%,the average was 84.51% and the above showed that the coal reservoir in the area was less saturated reservoir.The critical desorption pressure was 1.22~9.10 MPa and the average was 3.25 MPa.The theoretical mining recovery rate was ranging from 19.96%~46.15% and the average was 34.51%.In main geological factors affected to the adsorption of the coal reservoir,the coal reservoir pressure and the reservoir depth would have obvious positive relationship to the gas content and meanwhile,the higher metamorphic degree of the coal reservoir,the more developed of the micro pore and small pore in the seam would be and the higher adsorption capacity of the methane would be.