| Project/Area Number |
11650076
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Tohoku University |
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Principal Investigator |
ITO Takatoshi Institute of Fluid Science, Tohoku University, Associate Professor, 流体科学研究所, 助教授 (00184664)
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| Co-Investigator(Kenkyū-buntansha) |
SAITO Hiroyuki Institute of Fluid Science, Tohoku University, Research Associate, 流体科学研究所, 助手 (70264091)
HAYASHI Kazuo Institute of Fluid Science, Tohoku University, Professor, 流体科学研究所, 教授 (30111256)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1999: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Non-destructive test / Stress measurement / Electrical property / Specific resistivity / Rock / In-situ stress / Borehole |
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| Research Abstract |
It is known that electrical resistivity of rocks are defined as a function of porosity, pore inter-connectivity and resistivity of pore fluid. Resistivity of rocks changes with also stress as has been shown experimentally by Glover et al.(1994). Such dependency of resistivity on stress is likely, since porosity and pore inter-connectivity should change with stress condition. On the other hand, when a borehole is drilled into a formation, a stress disturbance is introduced in the vicinity of the borehole. As inferred from the relationship between resistivity and stress, the stress disturbance possibly induces an additional disturbance in resistivity around the borehole. The resistivity disturbance should be a function of remote stresses as same as the stress disturbance. Therefore, it may be possible to estimate remote stresses from resistivity distribution around the borehole, if we can measure the resistivity distribution somehow. To accomplish this idea, first we conduct laboratory experiments to measure resistivity of rock under uniaxial loading condition by using a cylindrical specimen. Then we examine how the specimen's resistivity in axial and transverse directions of the specimen changes with axial loading. Based on these results, we propose a new method to estimate in-situ stress state from resistivity distribution in the vicinity of borehole.
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