Rearch on gas geological condition of Weifang mining area, Shandong Province, China

摘要

This article analyzed the geological conditions of the gas in Weifang mining area from aspects of the regional hydrogeology, the fault and the fold, the roof and the floor lithologic characteristic, the distribution of magmatic rock and the thickness of the coal seam roof. The study shows that the Zhuliu coal mine is of moderately complicated hydrogeology type; most of the faults in Wutu coal mine and all the faults in the other 5 coal mines are normal faults, belonging to open faults. The faults generally have water conductivity, which are beneficial to gas drainage; the roof and floor, most of which are mudstone, shale, claystone, and some sandstone and limestone with joint and bedding, have poor stability, which contributes to the overflow of the gas. The wide distribution of magmatic rocks in Wujing coal mine remarkably impacts the gas reservation, thus the gas emission is higher than the other 5 coal mines. The low thickness and lithology of coal seam roof are in favor of the emission of gas. For the reasons given above, the 6 coal mines of Weifang mining area are all low gas field. This article also predicted the gas content and the absolute gas emission of Weifang mining area.