Injecting pure N2 and CO2 to coal for enhanced coalbed methane: Experimental observations and numerical simulation

Zhou, Fengde, Hussain, Furqan and Cinar, Yildiray (2013) Injecting pure N2 and CO2 to coal for enhanced coalbed methane: Experimental observations and numerical simulation. International Journal of Coal Geology, 116-117 53-62. doi:10.1016/j.coal.2013.06.004


Author Zhou, Fengde
Hussain, Furqan
Cinar, Yildiray
Title Injecting pure N2 and CO2 to coal for enhanced coalbed methane: Experimental observations and numerical simulation
Formatted title
Injecting pure N2 and CO2 to coal for enhanced coalbed methane: Experimental observations and numerical simulation
Journal name International Journal of Coal Geology   Check publisher's open access policy
ISSN 0166-5162
1872-7840
Publication date 2013-09-01
Year available 2013
Sub-type Article (original research)
DOI 10.1016/j.coal.2013.06.004
Open Access Status Not yet assessed
Volume 116-117
Start page 53
End page 62
Total pages 10
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Language eng
Formatted abstract
Enhanced coalbed methane (ECBM) core flooding experiments are a direct way to observe the gas displacement process, the competitive adsorption and the effect of coal swelling and shrinkage on coal permeability. This study reports two ECBM experiments. In the first experiment, pure N2 is injected (N2-ECBM) to a coal sample saturated with CH4 while, in the second experiment, pure CO2 is injected (CO2-ECBM) to the same coal sample cleaned and resaturated with CH4. We record the volumes and composition of the effluent gas with respect to time. Then the gas rate and gas composition are history matched using a commercial reservoir simulator. The results show that the breakthrough of N2 occurs earlier than CO2 breakthrough (after approximately 0.1day of injection compared to 0.43day). The recovery factor of CH4 is 71% for the N2-ECBM and 86% for the CO2-ECBM at a 10%-molar percentage of CH4 in the produced gas stream. The N2 injection causes moderate increases in coal permeability whereas the injection of CO2 reduces coal permeability significantly. The maximum strain of CO2 injection is higher at the initial stage of CO2 injection but decreases after several days of injection. The extended Langmuir adsorption model predicts the compositional adsorption amounts of N2 and CH4 better for the N2-ECBM than for the CO2-ECBM. A co-optimisation concept is presented to analyse the coupling of ECBM with CO2 storage which shows that early times CO2 storage efficiency is higher than CH4 recovery efficiency. Later CO2 storage efficiency decreases due to CO2 production and CH4 recovery dominates the co-optimisation.
Keyword Coal
Core flooding
ECBM
Numerical simulation
Qinshui Basin
Q-Index Code C1
Q-Index Status Provisional Code
Grant ID CUGL100249
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Earth Sciences Publications
 
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Created: Mon, 05 Sep 2016, 23:32:21 EST by Anthony Yeates on behalf of Learning and Research Services (UQ Library)