Analysis on the permeability of coal measures by the use of borehole logging data

Analysis of the permeability of coal measures effected by mining with the help of TV borehole imaging can be significant for reasonable layout of gas drainage hole system. Geophysical logging data (gamma, density) obtained from boreholes can be used for evaluating formation boundaries, shale contents, interlayer and weak layers. The permeability in the study area is different when working face advances. Overlying strata failure height can be made sure by permeability calculated by logging data and borehole television. Conclusion can be obtained as follows:the location of formation boundaries, shale contents, interlayer and weak layers can be confirmed in original logging data, increased permeability area evolves from formation boundaries between shale, claystone and other strata and original fracture zone to interlayer of pure strata and weak layers after mining; caved zone depth is 433 m and fractured zone depth is 382 m.