Reservoir characteristics and recoverability of CBM resource in Duge coalfield of western Guizhou

To evaluate the CBM recoverable potential of Duge coalfield in western Guizhou province and promote the development of CBM in multiple thin coal seams,the formation condition of coal seams and adjacent roof and floor,the reservoir pressure,gas content,porosity and permeability are discussed based on the geological data from CBM wells in Duge coalfield. The recoverable coefficient is predicted using isothermal adsorption curve,similar coal seams analogy and production data fitting. The results show that the gas content of Duge coalfield is 3. 94-29. 95 m3 / t,12. 48 m3 / t in average,and the average gas saturation is 60% . The pressure of most coal seams is normal. The coal seams are of high gas content and gas saturation,and large porosity and permeability. The recoverable coefficients predicted by isother- mal adsorption curve,similar coal seams analogy and production data fitting are 0. 49 -0. 68,0. 40 -0. 53 and 0. 41, which is evaluated as 0. 41-0. 68 comprehensively. High CBM recoverable coefficient indicates good geological condi- tions and development potential of the coal seams in Duge coalfield.