資源開発技術・岩盤工学

[2201-10-04] Transient Stress Disturbances Induced Change in Permeability of Kushiro Cretaceous Sandstone

○Sophea BOEUT¹, Teppei OSHIMA¹, Yoshiaki FUJII¹, Jun-ichi KODAMA¹, Daisuke FUKUDA¹, Hiroyuki MATSUMOTO², Kazumi UCHIDA² (1. Hokkaido University, 2. Kushiro Coal Mine)

司会：笹岡 孝司（九州大学）

Keywords:Transient stress disturbances, Axial stress, Pore pressure, Permeability, Kushiro Cretaceous sandstone

These phenomena might be induced by change in transient stress disturbances from these etc. in paperback the change in permeability of Kushiro Cretaceous sandstone by transient stress disturbances which change might be potentially used for the enhanced methane gas recovery at Kushiro Coal Mine. The saturated specimens with the dimension of 30 mm in diameter and 60 mm in length under triaxial compression to the axial stress or pore pressure disturbances.Under axial stress disturbance amplitudes of 0-11 MPa and confining pressure of 3-15 MPa, The permeability of the specimens decreased by the disturbances for both pre-post-failure, the reduction amount is greater than was with a greater than confidence pressure but kept almost constant with stress disturbance amplitudes.Under pore pressure disturbance amplitudes of 1.8 MPa and confining pressure of 10 MPa, the permeability of the intact specimen increased by the disturbance and continued increasing by failure, though it decreased by disturbances for the post-failure regime. by the transient pore pressure disturbances inducing microcracks, unclogging the micro-pathway, etc. This increase may be caused by the enhanced methane gas recovery.This increase may be caused by the enhanced methane gas recovery.This increase may be caused by the enhanced methane gas recovery.