Analysis of pore system model and physical property of coal reservoir in the Qinshui Basin

The Qinshui Basin in China is a major area for exploration and development of high rank coalbed methane. Due to the high rank coal and complicated pore system, no substantial breakthrough in the exploration and development of coalbed methane has been made until now. Many systematic tests show that a pore system of coal reservoir has some features as follows: the porosity is relatively low; the pore system is dominated by micropores and transition pores; mesopores take the second place, and macropores are nearly absent, which is exceedingly adverse for production of coal-bed methane. However, testing data also revealed the differential development for the pore of high rank coal reservoirs in the Qinshui Basin, which necessarily led to the different physical properties of desorption, diffusion and permeability. This paper classifies the testing data using cluster analysis method and selects the typical samples to establish four pore system models, analyzes the differences of reservoir physical property, and provides a guidance for the exploration and development of coalbed methane in the Qinshui Basin.