Simulation of coal permeability under non-isothermal CO₂ injection
by Hongyan Qu; Jishan Liu; Zhejun Pan; Yan Peng; Fujian Zhou
International Journal of Oil, Gas and Coal Technology (IJOGCT), Vol. 15, No. 2, 2017

Abstract: CO₂ injection into coal seams is a non-isothermal process, which has significant impact on coal permeability but has not been well studied. In this paper, a non-isothermal model coupled with nonlinear gas flow and matrix deformation was developed. The effects of temperature change on each term of the effective strain during the CO₂ injection scenarios, as well as the variations of fluid properties over a range of sub- and supercritical-thermodynamic conditions were investigated. This model involves the balance of thermal energy and the law of heat transfer. Two non-isothermal cases of CO₂ injection were studied and compared with the isothermal case. The results show that CO₂ injection into coal seams reduces coal permeability for all three cases. The coal matrix expands with temperature increase due to the thermal expansion and shrinks due to the decrease in adsorption amount. However, the final permeability with low-temperature CO₂ injection remains lower than that with high-temperature gas injection since the effect of sorption-induced strain on permeability outweighs that of the thermal deformation. The increase in temperature leads to the reduction in coal swelling (with the decrease of CO₂ adsorption capacity), resulting in larger cleat aperture and higher coal permeability for the cases studied in this work. [Received: November 29, 2015; Accepted: June 22, 2016]

Online publication date: Mon, 05-Jun-2017

The full text of this article is only available to individual subscribers or to users at subscribing institutions.

 
Existing subscribers:
Go to Inderscience Online Journals to access the Full Text of this article.

Pay per view:
If you are not a subscriber and you just want to read the full contents of this article, buy online access here.

Complimentary Subscribers, Editors or Members of the Editorial Board of the International Journal of Oil, Gas and Coal Technology (IJOGCT):
Login with your Inderscience username and password:

Username:        Password:          Forgotten your password?

Want to subscribe?
A subscription gives you complete access to all articles in the current issue, as well as to all articles in the previous three years (where applicable). See our Orders page to subscribe.

If you still need assistance, please email subs@inderscience.com