A better understanding on the multiscale transport of shale gas will further the advancement of shale gas extraction. Traditional lattice Boltzmann method (LBM) simulations usually underestimate the shale gas transport capacity due to the missed consideration of gas adsorption in nanometer-sized slit pores. Here, we proposed a multiscale LB model considering the adsorption effect to simulate the shale gas transport in micro/nano-pores. The adsorption parameters between organic wall and gas molecules were determined by molecular dynamics (MD) simulations. Multiscale transport mechanism of shale gas in micro/nano slit pores ranging from nanometer to millimeter was studied by, including three different flow characteristics, namely, viscous flow, slippage, and surface diffusion. In microscale pores (pore width H > 1 mu m), viscous flow is the dominated transport mechanism, where the velocity profile displays a typical parabolic shape without slip velocity. In larger nanoscale pores (10 nm

Keywords:Shale gas;Lattice Boltzmann method;Multiscale transport mechanism;Adsorption effect;Apparent permeability