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Repeatability and Reproducibility in Effective Porosity Measurements of Rock Samples

암석시험편 유효공극률 측정의 반복성과 재현성

  • Lee, Tae Jong (Korea Institute of Geoscience and Mineral Resources (KIGAM)) ;
  • Lee, Sang Kyu (Korea Institute of Geoscience and Mineral Resources (KIGAM))
  • Received : 2012.11.07
  • Accepted : 2012.11.21
  • Published : 2012.11.30

Abstract

Repeatability and reproducibility in solid weight and effective porosity measurements have been discussed using 8 core samples with different diameters, lengths, rock types, and effective porosities. Further, the effect of temperature on the effective porosity measurement has been discussed as well. Effective porosity of each sample has been measured 7 times with vacuum saturation method with vacuum pressure of 1 torr and vacuum time of 80 minutes. Firstly, effective porosity of each sample is measured one by one, so that it can provide a reference value. Then for reproducibility check, effective porosity measurements with vacuum saturation of 2, 4, and 8 samples simultaneously have been performed. And finally, repeated measurements for 3 times for each sample are made for repeatability check. Average deviation from the reference set in solid weight showed 0.00 $g/cm^3$, which means perfect repeatability and reproducibility. For effective porosity, average deviations are less than 0.07% and 0.05% in repeatability and reproducibility test sets, respectively, which are in good agreement too. Most of porosities measured in reproducibility test lies within the deviation range in repeatability test sets. Thus, simultaneous vacuum saturation of several samples has little impact on the effective porosity measurement when high vacuum pressure of 1 torr is used. Air temperature can cause errors on submerged weight read and even effective porosity, because it is closely related to the temperature, density, and buoyancy of water. Consequently, for accurate measurement of effective porosity in a laboratory, efforts for maintaining air or water temperature constant during the experiment, or a temperature correction from other information are needed.

Acknowledgement

Supported by : 한국에너지기술평가원(KETEP)

References

  1. 기상청, 2012, "대전지방기상청 구성동관측소 기상 자료".
  2. 이상규, 이태종, 2009, 전도성 간극수의 함수 정도에 따른 원주형 시멘트 시험편의 전기비저항 특성, 한국지구시스템공학회지, 제46권 5호, pp. 553-562.
  3. 이상규, 이태종, 2010, "건조과정에서 무게 모니터링을 통한 암석 시험편의 고체무게 산출 방법", 한국지구시스템공학회지, 제47권 2호, pp. 183-190.
  4. 이상규, 이태종, 2012, "수분분리기 및 이를 포함하는 수분 포획 장치", 대한민국특허청, 출원번호 10-2012-0065145.
  5. 이상규, 이태종, 이영민, 2012a, "습식 진공포화와 건식 진공포화에 의한 시험편의 유효공극률 비교", 한국지구시스템공학회지, 제 49권 3호, pp. 328-337.
  6. 이상규, 이태종, 김형찬, 2012b, "진공의 압력과 시간을 달리할때 시멘트시험편의 유효공극률 변화", 한국지구시스템공학회 제99회 추계학술발표회 논문집, pp. 197-199.
  7. 한국암반공학회, 2006, "암석의 공극률 및 밀도 측정 표준시험법", 터널과 지하공간, 16(2), 95-98.
  8. Barnes, K. B., 1931, A method for determining the effective porosity of a reservoir rock, The Pennsylvania State College Bulletin, 24, No. 28, Mineral Industries Experiment Station Bulletin 10, 13p.
  9. Dorsch, J., Katsube, T. J., Sanford, W. E., Dugan, B. E., and Tourkow, L. M., 1996, Effective porosity and pore-throat sizes of Connsauga Group mudrock: Application, test and evaluation of petrophysical techniques, Research Report ORNL/GWPO-021, Oak Ridge National Lab., 113p.
  10. ISRM, 1979, Suggested methods for determining water content, porosity, density, absorption and related properties and swelling and slake-durability index properties.
  11. Katsube, T. J. and Scromeda, N., 1991, Effective porosity measuring procedure for low porosity rocks, Geological Survey of Cananda, Paper 91-E, 291-297.
  12. Keithley Ins., 2006, 저준위 측정 핸드북 제6판 -정밀 직류 전류, 전압 및 저항 측정, No. 1559KR, 80450KSI.