Study on mechanical parameters and creep seepage characteristics of different coal and rock combination samples

Abstract Based on the fact that production of deep coalbed methane (CBM) in Yushe-Wuxiang Block is lower than expected, paper carried out uniaxial strength test and triaxial rheological coal measure strata reservoirs (mudstone, coal, sandstone their composite sample) deeper 1300 m block. In test, it found stress–strain process rock sample was similar to shallow one. The brittleness more obvious. It can also serve as described by four stages compression process. compressive combined samples will be improved a small range, while mudstone driven produce radial tensile failure at moment failure. Creep characteristics are those single one, axial deformation under stress (14 MPa, 18 22 MPa) close coal. extreme (26 30 34 sandstone. established stress-seepage coupled creep damage model used describe law each different stresses. permeability determined poor formation. There great correlation between volume evolution test. based theory porous media well fitted relationship volumetric strain permeability. significance predict influence effect in-situ stresses engineering.