Reservoir parameters and maceral composition of coal in different Carboniferous lithostratigraphical series of the Upper Silesian Coal Basin, Poland

Laboratory tests were carried out on coal samples taken from mine openings of selected coal mines in the Upper Silesian Coal Basin. The analyses involved maceral composition (vitrinite, inertinite and liptinite group) and vitrinite reflectance on the one hand, and reservoir parameters (coal permeability and effective porosity) on the other. The results are compared. Samples with high values of coal permeability are characterized by vitrinite contents of ca 60%, and samples with the lowest permeability by vitrinite contents of 40%. The vitrinite-rich bright coals are brittle and prone to crushing caused by tectonic pressures. Moreover, coal permeability is more strongly anisotropic in the bright coals of the Cracow Sandstone and the Mudstone Series than in the dull coals of the Upper Silesian Sandstone Series. In bright coals, permeability is much along the direction parallel to vitrain layers. Good reservoir parameters such as permeability and effective porosity are crucial for fluid flow through the coal seams and, thus, successful coalbed methane exploitation. In the Upper Silesian Coal Basin, Cracow Sandstone- and Mudstone Series with vitrinite-rich coals should be a good target, though serious geological problems must first be overcome. (C) 2012 Elsevier B.V. All rights reserved.