Investigation on the influence of the macropores in coal on CBM recovery

As an important component of coal structure, the macropores have a great influence on CBM recovery. In this paper, characteristic two samples collected from 3# seam in south Qinshui Basin, China was analyzed basic mercury intrusion porosimetry, and fully coupled triple-porosity/double permeability mathematical model for recovery established according to physical structure non-Darcy flow methane macropores. Then, various factors affecting were discussed size distribution connectivity investigated. The following conclusions been drawn these efforts: (1) extremely heterogeneous pore with high variation, their is not good because they are mainly composed conical cylindrical pores one dead end open pores, characteristics conducive recovery; (2) containing includes occurrence-migration field, hydraulic thermal field stress as well complex intercoupling between them, verified by fitting production history, average error 3.24%; (3) closely related Knudsen number controlled pressure temperature intrinsic which internal attribute affected pore; (4) drop reservoir plays major role permeability, promotes increase time, corresponding more improvement fracture rate during It recommended that seams including uniform should be preferentially used development CBM.