The permeability of the coal reservoir depends on the pore-fracture system of the coal reservoir, and the pore-fracture system of the coal reservoir depends on coal rank, coal lithotypes and maceral.

• 对一个特定的煤层气田而言,煤级变化不大或者规律明显。煤岩成分往往成为控制煤储层渗透率分布不均性的主导因素。煤岩成分,包括有机显微组分和矿物质均受控于煤相。