Study On Characteristics Of Gas Geology And Gas Drainage By Hydraulic In An-He Coalfield

An-He coalfield is taken as the study object and the regional tectonic evolution theory is used to reveal the coalbed gas geology rule,the results show that the differences of regional tectonic structure has led to the disequilibrium of gas occurrence.Buried depth of coal seam and tectonic structure are the main controlling factors that lead to high gas content in An-He coalfield,besides,the weighted gray correlation method is used to auxiliary determine the main factors.It will be significant to gas occurrence prediction and formulating gas controlling methods.Aiming at the widespread condition that the gas content of coal seam in Taiyuan Formation is lower than its overlying coal seam of Shanxi Formation,the formation and tectonic evolution of An-He coalfield geological structure are analysed,in the Cenozoic era,the limestone in Ordovician is exposed in the west of the coalfield,where rainfall drop and strong seepage flow took place,and the spring group is formed in the downthrow side of Qing yangkou fault in the east of the coalfield as the result of the karst water in the limestone,the gas in the Taiyuan Formation escaped into the air with the flow of the spring because of the hydraulic connection between the gas and the water in the limestone of the Ordovician underlying the Taiyuan Formation,which causes the low gas content generally in the coal seam of Taiyuan Formation.This research conclusions are of theoretical guiding significance for carrying out regional gas forecast,gas prevention,the coal mine safety production and gas exploitation in similar to roof or floor of coal seam where strong hydraulic power exist in An-He coalfield.