Experimental Studies on Coal Permeability Characteristics under Different Pore Pressure

Abstract

Using a self-developed triaxial seepage device, tests of coal samples from Liu Panshui coal mine were carried out to explore the relationship between permeability and pore pressure when effective stress and temperature conditions keep constant as well as the impact of pore pressure on gas seepage. The research results show that: Permeability decreases with the increase of pressure difference between inlet and outlet Δp when effective stress and temperature keep constant; permeability declines in a nonlinear tread with increase of pore pressure and they all have a exponential relationship; when pore pressure is low, permeability decreases faster with changes in pressure difference between inlet and outlet Δp. When gas pressure is low, with pore pressure increasing the gas flow pore narrowed.