HR: 0800h
AN: T51A-1323    [Abstracts]
TI: The Stress-dependent Permeability/Porosity Of Drilled Cores From TCDP Hole-A
AU: * Dong, J
EM: jjdong@geo.ncu.edu.tw
AF: Institute of Applied Geology, National Central University, No.300, Jungda Rd, Jungli, 320 Taiwan
AU: Hsu, J
T51A-1323 AF: Institute of Applied Geology, National Central University, No.300, Jungda Rd, Jungli, 320 Taiwan
AU: Wu, Y
EM: 93622004@cc.ncu.edu.tw
AF: Institute of Geophysics, National Central University, No.300, Jungda Rd, Jungli, 320 Taiwan
AU: Hung, J
EM: jhung@earth.ncu.edu.tw
AF: Institute of Geophysics, National Central University, No.300, Jungda Rd, Jungli, 320 Taiwan
AU: Yeh, E
EM: yeh@jamstec.go.jp
AF: Japan Agency for Marine-Earth Science and Technology, JAMSTEC, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, 2360001 Japan
AB: Accurate determination of the permeability and porosity of the rock cores from TCDP is important to explore the Chi-Chi earthquake mechanisms. In this study, experimental results of the permeability and porosity under different effective confining pressure of core samples from TCDP hole-A were presented. The system used in NCU for gas/water steady flow and porosity measurements (confining stress up to 200MPa) is developed by professor Shimamoto, Kyoto University. Steady gas flow method is used to derive the permeability of sandstone and siltstone. Under cyclic pressure, permeability is smaller in siltstones than sandstones by about three to six orders of magnitude. Porosity of tested sandstone and siltstone samples under effective confining stress ranging 3-120 MPa are 20%-15% and 10%-8%, respectively. It is interesting to find that permeability is more sensitive to effective confining pressure in siltstone than sandstone but vice versa for porosity. Porosity derived from core measurements were also compared to that derived from sonic log at the interval of 508 to 1865 m. The sonic porosity is 60% higher than the porosity measured from intact core samples. Thus fractures play an important role on the measured in-situ porosity and probably permeability also. Consequently, effects of fractures on the porosity/permeability should not be neglected.
DE: 5114 Permeability and porosity
SC: Tectonophysics [T]
MN: Fall Meeting 2005