Abstract

“ñŽ_‰»’Y‘f‹z’…‚É”º‚€Î’Y‚Ì–c“Á«‹y‚ѐZ“§«‚ւ̉e‹¿‚ÉŠÖ‚·‚éŽÀŒ±“IŒ€‹†
Ž‘Œ¹‚Æ‘fÞ, 121, 231-239, 2005.
åL Ž©‹, ‘å‹÷ ‘œ‰ÁŽu

Laboratory measurements on coal matrix swelling were carried out during CO2 injection, by monitoring strain and P-wave velocity changes. Cylindrical Coal samples were drilled from large blocks collected from Kushiro Coal Mine, Hokkaido. Fractured and intact samples were used to investigate swelling behaviors and its effect on permeability, respectively. Swelling strains are much larger due to CO2 adsorption compared to N2 adsorption at the same coal sample. Results of the intact coal sample show that the sample permeability decreased by about 50% associated with CO2 adsorption. Both P-wave velocity and amplitude increased significantly caused by the coal matrix swellling. Our results suggest that coal matrix swelling due to CO2 adsorption caused cleat closure and the cleat closure reduced coal permeability.

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