AUTHOR=Hu Zantong , Deng Yonghong , Li Jingxuan , Wu Xiaojun , Bai Jinmei , Tian Junqiang 

TITLE=Modified experimental method to investigate micro transport in the shale matrix for shale gas production

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 11 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2023.1260499

DOI=10.3389/fenrg.2023.1260499

ISSN=2296-598X

ABSTRACT=Matrix permeability is the primary transport property for shale gas recovery, due to the special production process of gas from matrix to wellbore. Despite of the micro pore size of shale matrix, the obtained permeability from macro experimental techniques has not considered micro transport mechanisms. In this study, pressure drop curves of shale matrix at high- and low-pressure experimental conditions were obtained, and were analyzed by modified numerical model with micro transport mechanisms. As selected parameters, porosity, pore radius and tortuosity were regressed to obtain apparent permeabilities of three samples. Tortuosity is much higher than macro one, and was proved to be necessary and reasonable. By analysis, the Knudsen diffusion and slippage effect control the micro transport of shale matrix at low and high pressure, separately, which is the main difference of macro and micro transports. Slippage flow weight factor helps to the increase of slippage flow proportion with pressure. Higher pore radius and tortuosity both could weaken the effect of Knudsen diffusion, and slippage flow appears positive relationship with pore size at high pressure. This research provides an inspiration to shale transport study and a micro perspective theoretical guidance for the macro recovery of in-site shale gas reservoir.