TITLE:
The Effectiveness of the Continuous and Cyclic Method on CO2-ECBM
AUTHORS:
Theodora Noely Tambaria, Yuichi Sugai
KEYWORDS:
Coalbed Methane, CO2 Injection, Desorption Efficiency
JOURNAL NAME:
Natural Resources,
Vol.15 No.3,
March
15,
2024
ABSTRACT: This study examines the impact of different CO2 injection methods on coalbed
methane recovery. Specifically, this study investigated the effectiveness of
continuously
injecting CO2 versus injecting CO2 that had been soaked for two weeks. The objective
was to ascertain which approach was more successful in enhancing CO2 Enhanced coalbed Methane (CO2-ECBM). The experiment involved injecting 3 MPa of
CH4 into dry coal samples, allowing it to adsorb until reaching
equilibrium, and then injecting 5 MPa of CO2 to recover adsorbed CH4. The continuous method recovered CH4 without detectable effluent concentration for 5
hours, but desorption efficiency was only 26% due to fast flow. On the other
hand, the desorption efficiency of the cyclic method was only 12%, indicating
trapped CH4. A comparison of desorption efficiency per unit of time shows the
continuous method is more effective than the cyclic method. The results of this
study demonstrate the continuous method is more effective for the desorption of
CH4, and its efficiency can be improved by briefly soaking CO2 on coal and then reinjecting it to maximize CH4 recovery. It is advisable to limit the soaking time to prevent excessive
swelling of the coal matrix, which can hinder seam flow and harm long-term gas
production.