The apparent permeability and effective porosity of organic-shale nanopores are time-varying under the impacts of gas adsorption/desorption, non-Darcy flow, and stress dependence during gas production. However, the porosity occupied by adsorbed gas is usually disregarded by industry standard. Moreover, the gas flow regimes are not completely described in most models or simulators; the stress dependence of matrix does not draw adequate attention in current studies. Therefore, an appropriate modeling is urgently needed to simulate the dynamics and performances during gas production. In this paper, we developed a coupled model to characterize time-variation properties by considering contributions of gas adsorption, non-Darcy flow, and stress dependence. After that, we verified the model and demonstrated model application, which lead to new insights into the evaluation of rock properties and gas quantities during gas production. We found that taking account of the volume occupied by adsorbed gas can effectively avoid the significant error of OGIP (Original Gas in Place) in the classical models. Meanwhile, the apparent permeability is significantly reduced by adsorbed gas, but the time-varying apparent permeability affected by gas flow regimes increases during gas production. We also studied the complex behaviors of the effects of stress dependence and various flow regimes. This new model provides with a more clear understanding of the time-varying features of organic-shale nanopores during gas production, which is more advantageous than classical models. As the production process can be more accurately forecasted, more insights can be achieved by the improved simulations.

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