Lattice Boltzmann method for simulation of shale gas flow in kerogen nano-pores considering temperature dependent adsorption

摘要

Due to the combined action of gas adsorption, surface diffusion and slippage, classical simulation approaches based on Darcy's law may not be appropriate for simulating shale gas flow in shale. In this work, a novel lattice Boltzmann (LB) model is proposed to study shale gas flow in a kerogen pore by introducing temperature dependent thickness of adsorption layer. The surface diffusion, which is caused by gradient of adsorption density, is considered as the slippage velocity on the surface of adsorption layer. The proposed LB model was adopted to simulate shale gas flow in a nano-pore. The results show that adsorption can significantly decrease the permeability of nano-pores. Surface diffusion improves the gas movement in nano-pores at lower pressure. With the decrease of pore size, the adsorbed layer had more impacts on gas permeability. Increasing temperature improves gas flow ability in nano-pores when pore size is less than 10nm. [Received: December 18, 2017; Accepted: May 2, 2018]