An integrated workflow to characterize lower Eagle Ford shale for hydrocarbon gas huff-n-puff simulation

•Gas diffusion impacts the mobilization of extractible bitumen deeper in the matrix.•Increase in permeability and porosity reflects fundamental changes in the pore network.•Tortuosity is estimated for different shale volumes for gas huff-n-puff simulation.•High resolution imaging reveal the microstructure and paragenesis of the pore system.