Research on Gas-geology Law of Ji₁₅ Seam in No.12 Mine of Pingdingshan

Using gas geological theory,combing with the geological exploration and the gas geological data revealed in the mine production, the article reseraches the gas-geology laws of the Ji₁₅ seam of Pingdingshan No.12 Mine.The research also analyzed the effects of geological tectonic,thickness of coal seam, the lithologies of coal seam roof and floor, burial depth of coal seam and the overlying bedrock thickness on the gas occurrence.The research revealed that the geological tectonic controled the gas occurrence and distribution of Ji₁₅ seam.Controlled field by the structure is divided into the south area of Niuzhuang syncline,the area between Niuzhuang syncline and Guozhuang anticlinal and the north area of Guozhuang anticline three gas-geological units.The article analyzed the control of structure on gas occurrence of each gas geological unit.The thickness of Ji₁₅ is big and coal seam is bedding sliding,the tectonic coal developed with stratification,the direct roof and floor lithologics are mostly sandy mudstone and shale and thickness changes little,which is good for gas occurrence.The vertical difference of No.12 Mine quaternary loose layer is big,the thickness of oveylying bedrock is more accurate than coal buried depth on gas occurrence.The thickness of the overlying bedrock controls gas occurrence of each geologic unit.