Coal Reservoir Property Differences Analysis of Different Macrolithotype in Liulin Mining Area

This paper focused on the influences of different coal macrolithotypes on the coal reservoir properties, using a variety of testing methods studied the connection between macro-lithotype of coal and properties. When coal lithotypes changing from dull coal, bright coal, semibright coal to semidull coal, the adsorption pores change from enclosed types to open, adsorption capacities improved in turn, which is favorable to adsorption, desorption and diffusion of coalbed methane. Seepage pores of bright coal are the most developed, semidull coal and semibright coal less, dull coal the least. The permeability of coal has a positive correlation between microfissure density and large pore content. Different macrolithotype of the same coal seam changes with the permeability could be divided into three stages, including fractures decrease rapidly stage, fractures decrease slowly stage and fractures tend to be closed stage.