Potential Analysis of Coalbed Methane Drainage in Guizhou Songhe Coal Mine

Based on the data of coal and CBM exploitation, we analyzed the geology of CBM exploitation, permeability and gas content of coal reservoir stratum in detail in Songhe Coal Mine, and estimated the CBM resources, and comprehensively evaluated the CBM surface drainage potential of this area. We revealed that Songhe Coal Mine has a good preservative condition of CBM. Coal seams in this area present the characteristics of thin thickness and multi-seam group. The burial depth of coal-bed, coal structure, permeability and gas content are relatively well. The burial depth of coal-bed had a obvious control on gas content of coal-bed, and the abrupt gradient depth of gas contenting is 300 m to 400 m, the CBM resource is as high as 66.96×10⁸ m³. The No. 6 well in Songhe Coal Mine adopted the technology of "multistage co-layer fracturing and co-layer drainage"; the gas production of single fracture zone in single well is over 1 000 m³/d for long term by using these technologies, while the gas production fluctuated obviously, therefore, strengthening the research of interlayer problems of co-layer drainage was suggested. Due to the limitation of the topography, transportation and geological conditions in this area, a development mode with "surface cluster wells drilling and multistage co-layer fracturing" was provided for the development of this area.