Title: Analysis of adsorption kinetics and thermodynamics of methane in shale based on the volume filling theory of micropores

Authors: Shuai Yin; Runcheng Xie; Jingzhou Zhao

Addresses: School of Earth Science and Engineering, Xi'an Shiyou University, Xi'an 710065, China ' State Key Lab of Oil and Gas Reservoir Geology and Exploitation, and College of Resources, Chengdu University of Technology, Chengdu 610059, China ' School of Earth Science and Engineering, Xi'an Shiyou University, Xi'an 710065, China

Abstract: Volume filling of micropores is an adsorption behaviour of adsorbates at higher equilibrium pressures. In this paper, the meaning of the parameters defined in the volume filling theory of micropores is discussed, and the adsorption performance of methane in shale is analysed. Research indicates that it is most appropriate to use the characteristic index curve n = 1 to describe the adsorption behaviour of methane in shale. As adsorption capacity increases, the differential adsorption work (A) will decrease. As the temperature increases, the characteristic energy (E) tends to decrease gradually, and for the case of n = 1, the values of E for shale samples ranged from 4.14 to 5.63 kJmol−1. As the filling rate θ increases, the absolute values of the thermodynamic parameters (Q, ΔH and ΔS) decrease gradually. Under experimental P-T conditions, the values of the thermodynamic parameters change very regularly and do not have mutation characteristics. This indicates that the adsorption energy can be extrapolated under much wider supercritical conditions. We believe that the thermodynamic parameters actually represent the complementarity and comprehensive effects of the TOC and Ro parameters. [Received: April 20, 2017; Accepted: July 8, 2017]

Keywords: micropores; volume filling; shale; methane; thermodynamic parameter.

DOI: 10.1504/IJOGCT.2019.099523

International Journal of Oil, Gas and Coal Technology, 2019 Vol.21 No.1, pp.26 - 38

Received: 20 Apr 2017
Accepted: 08 Jul 2017

Published online: 08 May 2019 *

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