Gas-geology Law And Gas Forecast Of8#Coal Seam In Junlian Mining Area

In this paper，taking8#coal seam of Junlian Mine area as the aimed object，collecting mine gas data,using regional geological evolution theory and tectonic cascadecontrol theory to research tectonic evolution、distribution of Tectonic stress field andcharacteristics of structural control of the Sichuan basin and its southern margin. On thebasis of geological unit of the divided gas, it analyzed the impact of different geologicalfactors on seam gas deposit and it predicted the content of coal seam gas and theemission of coal seam gas,and it divided weathering zone of coal seam gas, and theprediction of prominent risk of coal and gas area. Junlian mining area is located inxuyong~junlian superimposed fold belt where is in an ancient land mass of the upperYangtze western in Sichuan foreland basin southern. From the end-Permian toMesozoic，mining area after tension-dive-squeeze–uplift，constituted a completeorogenic cycle，developing a large number of secondary faults and layer-slip tectonic，within the mining area mainly developed in the EW、SN and NE tectonic zone. Minegas geology has partition and zonation apparently, the depth of coal seam, the seamfloor elevation and the thickness of seam on bedrock, three of them is the main factorsto affect the gas occurrence of coal seam,the content gradient for gas is2.55~5.39m~3/t/100m,the weathering of coal seam of gas with a lower limit for the depthis between70m to~310m.The total number of CBM resources for coal-bed was757.62billion m~3, and the average resource abundance was0.70×10~8m~3/km~2.