铁法大兴井田煤层含气性特征及其地质控制因素分析

he distribution characteristics of coalbed methane in Daxing mine field and the influence factors were investigated based on the data of geologic surveying and the coal core desorption of the new CBM wells. Results suggest that :(1) the range of gas content in this area is 3.1~10.3m3/t ,the trend is first increases then decreases with increasing depth. Generally the gas content of northern area is higher than the southern area, and showed a decreasing trend from west to east; (2) The gas content is cooperatively controlled by several geological factors such as geological structure, sedimentary system, magma intrusion, hydrodynamics and sedimentary characteristics of coal seam. Among which the tectonic fault sealing septum, baking and effective caps of the igneous rock layer, and hydrodynamic conditions are dominant.