The researchers studied the pores in Upper Permian coal in western Guizhou to understand how they affect the storage and movement of coal bed gas. They found that the porosity of the coal ranges from 1.4% to 9.5% and decreases from north to south. Most pores are adsorption pores, with semi-enclosed pores being common in high-rank coal. High-rank coal has poorer permeability and connectivity compared to low-rank coal but is better than in Qinshui basin overall. The coal rank is the main factor influencing porosity, with porosity increasing with coal rank.