11:00 〜 11:15
[HSC06-08] Experimental investigations of frictional strength and permeability properties of SWH core samples for the geomechanical modeling at Perth Site, Australia
キーワード：摩擦強度、浸透率、断層、ジオメカニクスモデリング
Understanding fault deformation and stability induced by a fluid injection in the subsurface is crucial for the widespread deployment of CO2 geological storage. A direct fluid injection test into the F10 fault zone, utilizing optical fiber techniques, is currently being conducted at the South West Hub (SWH) site in southern Perth, Australia.
The purpose of our study is to develop hydro-geomechanical modeling to accurately evaluate the field data acquired. Particularly, for model development, we measure concurrent flow and frictional strength of the SWH core sample to recover frictional stability and water-permeability evolution based on rate- and state-dependent friction models using the direct-shear testing.
Our results show that for the Harvey 3A_1434m sample, which is part of the SWH site core series, the maximum friction coefficient (um) exceeds 1.0, in contrast to that of shale (um ≈ 0.6, which is corresponding to a typical m value). In terms of friction stability (a-b), unstable behavior is also observed with increasing displacement, despite being exhibited stable behavior. According to post-shearing phase analyses, the observed higher frictional strength and changes in its trend can be attributed to finer grinding of rock fragments (e.g., quartz, K-feldspar) during slip. On the other hand, water permeability value was maintained at a certain level at a given displacement, indicating that the finer-griding effect does not significantly affect fluid flow behavior.
The findings of our study may provide a significant contribution to the understanding of the friction and permeability relationship for the development of geomechanical modeling at the SWH site.
The purpose of our study is to develop hydro-geomechanical modeling to accurately evaluate the field data acquired. Particularly, for model development, we measure concurrent flow and frictional strength of the SWH core sample to recover frictional stability and water-permeability evolution based on rate- and state-dependent friction models using the direct-shear testing.
Our results show that for the Harvey 3A_1434m sample, which is part of the SWH site core series, the maximum friction coefficient (um) exceeds 1.0, in contrast to that of shale (um ≈ 0.6, which is corresponding to a typical m value). In terms of friction stability (a-b), unstable behavior is also observed with increasing displacement, despite being exhibited stable behavior. According to post-shearing phase analyses, the observed higher frictional strength and changes in its trend can be attributed to finer grinding of rock fragments (e.g., quartz, K-feldspar) during slip. On the other hand, water permeability value was maintained at a certain level at a given displacement, indicating that the finer-griding effect does not significantly affect fluid flow behavior.
The findings of our study may provide a significant contribution to the understanding of the friction and permeability relationship for the development of geomechanical modeling at the SWH site.