This work introduces an experimental technique to probe simultaneously flow and diffusion of gas through shale. A core-scale pressure pulse decay experiment is utilized to study the upstream and downstream pressure responses of

Eagle Ford and Haynesville shale samples. With the aid of numerical models, the pressure curves obtained from the experiments are history-matched, and gas and rock properties are obtained. The experiments are conducted at varying pore pressure and net effective stress to understand the sensitivity of the rock porosity and permeability as well as the gas diffusivity. A dual porosity model is constructed to examine gas transport through a system of micropores and microcracks. In this sense, the role of the two different size pore systems is deconvolved. In some cases, the micropore system carries roughly a third of the gas flow. The porosity, permeability, and diffusivity obtained assign physical properties to the macro- and micro-scales simultaneously. Results bridge the gap between these scales and improve our understanding of how to assign transport physics to the correct pore scale.

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