关键词: 沁水盆地, 煤层气, 储层特征, 排采制度

Abstract: Coal petrology and properties, depth, thickness, properties, temperature and pressure, hydrocarbon content and isothermal adsorption properties characteristics of 15# coal bed in Qiyuan first coal mining area were analysed. Thickness of 15# coal bed is stable, average is 3.37m. Buried depth is moderate, average is 730m. Coal petrology is given priority to half light type, thermal evolution degree is higher, vitrinite reflectance is 2.5%~3.15%, the range of CBM content is 4.02m3/t to 17.13m3/t, average is 13.50m3/t. These conditions are conducive to development of CBM of the 15# coal。But the average porosity is 5.85%, the average permeability is 0.43mD, belongs to low porosity low permeability reservoir. These conditions are not conducive to development. According to the geological characteristics of 8 groups of u-shaped horizontal well, the key factors impacting production of the CBM is quantitative production system with accurate control of the pressure drop. The results show that the pressure drop rate of pre-desorption time is 3.8~7.7times of after desorption time, the pressure drop rate of pre-desorption time is 8.8~10.5kPa/d, the pressure drop rate of after desorption time is 1.9~2.5kPa/d.