Vertical distribution features of physical properties of coal reservoir in shaft QM-1 of Datong block of Qijiang area

In order to investigate the potential of coalbed methane development in Datong block with lower degree of coalbed methane exploration, the vertical characteristics of the main coal seams in shaft QM-1 were systematically analyzed with respect to their porestructure and gas content on the basis of mercury intrusion method, isothermal adsorption and gas content tests. The results showed that coal in shaft QM-1 is dominated by thin and medium-thick seams with primary and cataclastic texture. The middle part of the seam M₈ refers to the fragmented coal with low-porosity and extra-low-permeability. Pores of the lower part of the seams M₈ and M₁₂ are mainly adsorption pore which shows high adsorption capability. Main coal seams in shaft QM-1 have high gas content and in particular seam M₈ has saturated adsorption state. The study area generally has a good resource potential and development prospect of coalbed methane. However, it is would be challenging for coalbed methane development because of the diversity and complexity of the main coal seams vertically.