지구물리와물리탐사 (Geophysics and Geophysical Exploration)

  • 제21권4호
  • /
  • Pages.220-230
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  • 2018
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  • 1229-1064(pISSN)
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  • 2384-051X(eISSN)
한국지구물리·물리탐사학회 (Korean Society of Earth and Exploration Geophysicists)
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항온항습 환경에서 울릉도 시추코어의 건조·수포화 열전도도

Thermal Conductivity of Dry and Saturated Cores from Ulleung Island in a Constant Temperature and Humidity Condition

  • 이근수 (한국지질자원연구원 심지층연구센터) ;
  • 이상규 (한국지질자원연구원 심지층연구센터) ;
  • 이태종 (한국지질자원연구원 심지층연구센터)
  • Lee, Keun-Soo (Center for Deep Subsurface Research, Korea Institute of Geoscience and Mineral Resources (KIGAM)) ;
  • Lee, Sang Kyu (Center for Deep Subsurface Research, Korea Institute of Geoscience and Mineral Resources (KIGAM)) ;
  • Lee, Tae Jong (Center for Deep Subsurface Research, Korea Institute of Geoscience and Mineral Resources (KIGAM))
  • 투고 : 2018.09.03
  • 심사 : 2018.11.26
  • 발행 : 2018.11.30
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초록

상온 환경에서 PEDB (Portable Electronic Divided Bar) 시스템을 이용하여 암석의 열전도도를 측정할 경우 실내온도 변화에 영향을 받는다. 따라서 온도와 습도를 일정하게 조절할 수 있는 항온항습기 내에서 열전도도를 측정하면 상온 환경에서 측정할 때의 단점을 보완할 수 있다. 이 연구에서는 항온항습 상태에서 열전도도를 측정할 수 있는 시스템을 구축하여, 울릉도의 GH3, GH4 시추공에서 채취된 45개 시편에 대해 항온항습기 내에서 건조 및 수포화 열전도도를 측정하고 그 특성을 살펴보았다. 또한, 16개 시편에 대해 밀도 및 유효공극률을 측정하여 열전도도와의 상관관계를 분석하였다. 열전도도와 유효공극률 및 밀도의 상관성 분석결과, 수포화 시료보다는 건조시료에서 보다 높은 상관성을 보였으며, 특히 "수포화/건조 열전도도비"는 유효공극률과 매우 높은 상관성($R^2=0.90$)을 보였다.

When thermal conductivity of rock is measured with PEDB (Portable Electronic Divided Bar) in a laboratory, it can be greatly influenced by the change of room temperature. Therefore, measuring the thermal conductivity in a thermo-hygrostat is necessary, where it can remain in its constant temperature and humidity condition. In this study, a system for thermal conductivity measurement in a thermo-hygrostat has been set up and the thermal conductivities for the 45 samples collected from GH3 and GH4 boreholes in Ulleung Island have been measured both in dry and saturated conditions. Also, the correlations between those thermal conductivities, density, and effective porosity have been discussed. As a result of correlation analysis among the thermal conductivity, density, and effective porosity, it showed higher correlation with dry samples than saturated samples. Especially, thermal conductivity ratio between saturated and dry conditions shows very high correlation ($R^2=0.90$) with effective porosity.

키워드

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Fig. 1. Diagram showing principal components of the plates of the PEDB.

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Fig. 2. PEDB installation in a thermo-hygrostat device.

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Fig. 4. Thermal conductivity of the samples from GH3 (a) and GH4 (b) in Ulleung Island as a function of depth.

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Fig. 5. Correlation analysis of effective porosity and density. (a) Porosity versus dry density, (b) porosity versus saturated density, (c) porosity versus solid density, (d) porosity versus density ratio (Sat./Dry density).

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Fig. 6. Correlation analysis of Thermal conductivity and density. (a) Thermal conductivity versus density, (b) thermal conductivity ratio (Sat./Dry) versus density, (c) thermal conductivity ratio (Sat./Dry) versus density ratio (Sat./Dry).

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Fig. 8. Correlation analysis of thermal conductivity and porosity. (a) Thermal conductivity ratio (Sat./dry) versus porosity, (b) relation between thermal conductivity ratio (Sat./dry) and porosity for different rock types.

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Fig. 7. Relation between thermal conductivity and porosity. (a) Porosity effect on thermal conductivity derived by a geometric mean model (Woodside and Messmer, 1961), (b) thermal conductivity versus porosity of rock samples obtained from Ulleung Island.

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Fig. 9. Distribution of thermal conductivity ratio for the samples from different depths of (a) GH3 and (b) GH4. Porosity distribution of (c) GH3 and (d) GH4 deduced from thermal conductivity ratio.

Fig. 3. Calibration curves obtained from the 4 different cases of measurement condition.

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Table 1. Calibration curve equations obtained from four different measurement conditions.

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Table 2. Thermal conductivity of the KU (fused quartz) standard samples.

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Table 3. The effect of applying vaseline on the circumferential surface of the saturated rock specimens.

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Table. 4. Comparison of Thermal conductivity for saturated and dry samples. (LT: Lapilli Tuff, Tr: Trachyte PTr: Porphyritic Trachyte, Tf: Tuff, TB: Tuff Breccia)

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Table 5. Comparison of dry and saturated thermal conductivity of the core samples from the two boreholes with respect to rock types.

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Table 6. Thermal conductivity, density, and effective porosity of core samples from Ulleung Island.

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참고문헌

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