Open Access Articles


Contact Us

Advances in Geo-Energy Research

Ausasia Science and Technology Press, Australia

E-mail: ager2017@126.com

Our Visitors

164631 visitors Look details

Investigation of methane adsorption mechanism on Longmaxi shale by combining the micropore filling and monolayer coverage theories

Shangwen Zhou, Yang Ning, Hongyan Wang, Honglin Liu, Huaqing Xue

(Published: 2018-06-28)


Corresponding Author and Email:Shangwen Zhou, zhousw10@petrochina.com.cn


Citation:Zhou, S., Ning, Y., Wang, H., Liu, H., Xue, H. Investigation of methane adsorption mechanism on Longmaxi shale by combining the micropore filling and monolayer coverage theories. Advances in Geo-Energy Research, 2018, 2(3): 269-281, doi: 10.26804/ager.2018.03.05.


Article Type:Original article


Abstract:

Understanding the methane adsorption mechanism is critical for studying shale gas storage and transport in shale nanopores. In this work, we conducted low-pressure nitrogen adsorption (LPNA), scanning electron microscopy (SEM), and high-pressure methane adsorption experiments on seven shale samples from the Longmaxi formation in Sichuan basin. LPNA and SEM results show that pores in the shale samples are mainly nanometer-sized and have a broad size distribution. We have also shown that methane should be not only adsorbed in micropores (< 2 nm) but also in mesopores (2-50 nm) by two hypotheses. Therefore, we established a novel DA-LF model by combining the micropore filling and monolayer coverage theories to describe the methane adsorption process in shale. This new model can fit the high-pressure isotherms quite well, and the fitting error of this new model is slightly smaller than the commonly used D-A and L-F models. The absolute adsorption isotherms and the capacities for micropores and mesopores can be calculated using this new model separately, showing that 77% to 97% of methane molecules are adsorbed in micropores. In addition, we conclude that the methane adsorption mechanism in shale is: the majority of methane molecules are filled in micropores, and the remainder are monolayer-adsorbed in mesopores. It is anticipated that our results provide a more accurate explanation of the shale gas adsorption mechanism in shale formations.


Keywords:Shale gas, adsorption mechanism, micropore filling, monolayer adsorption, nanopores, adsorption model.


Views:979
Downloads:277



Download this Manuscript:PDF

Copyright ©2016. All Rights Reserved
E-mail: ager2017@126.com