Characteristics of Tectonic Coal in 3^# Coal Seam of Eastern Qinnan Block and Its Influence on Permeability

Taking 3^# coal seam of eastern Qinnan block as the research object, based on the description results of CBM well drilling coring, the vertical characteristics and horizontal distribution of tectonic coal were studied, the influence of tectonic coal on permeability was further analyzed. The results show that at horizontal direction, the tectonic coal develops along faults, and more developed closer to the fault. The primary structure coal develops between two fault bands, and is relatively far away from the fault. At vertical direction, the fragmented coal and mylonitic coal develop near the direct roof and floor of the coal seam, while the cataclastic coal is mostly located in the central of the coal seam. The permeability of 3# coal seam is obviously higher in the northwest, middle and south of the research area, and decreases to the southwest, southeast and northeast. The primary structure coal and the cataclastic coal together affect the permeability of 3^# coal seam in the research area. They are in the elastic and elastic-plastic strain stages which promote the development of cleats and fractures in coal seam. That is the main reason for the high permeability of coal seam in the region primary structure coal and the cataclastic coal developed.