Abstract:

 China high coalrank coalbed methane basins have undergone multiphase of tectonic activity, which makes the high coalrank coalbed methane reservoirs of peculiar complexity. By the research on  the high coalrank coalbed methane reservoir of the Qinshui basin including the study of the coalbed thermal evolution level, the temperature and pressure of inclusion in calcite or quartz reef in coalbearing strata, the palaeogeothermal analysis of the fission track of apatite and zircon, the anogenic isotopic age, and the geothermal flux caused by magmatic activity, we have proved the existence of the tectonic thermal event. It is found from the experimental analysis of coal thermal decomposition that the high temperature and high pressure of the reservoir environment caused by the tectonic thermal event accelerates the hydrocarbon production in the coalbed, and raises the coal adsorptive capability, which make the gas content in the Qinshui basin 513 m3/t higher than that in the Black Warrior basin. Moreover, the change in temperature caused by the igneous intrusion is one of the reasons for the undersaturation of the gas content in the Qinshui basin, and the high temperature and high pressure of the reservoir environment improve the coal permeability. 

Key words:

Key words: the tectonic thermal event; high coalrank; coalbed methane; permeability; gas content.