Influence radius of gas extraction borehole in an ...
Coal is an anisotropy heterogeneous natural material containing both bedding and cleat structures. This unique feature makes coal to show anisotropy permeability, which was shown in extensive studies. 1619 Koenig and Stubbs 20 reported for Pratt A coal seam, the direction permeability goes up to 17:1 oriented parallel to the face cleat direction of coal, and the face cleats dominate the ...