The Journal of Engineering Geology (지질공학)

The Korean Society of Engineering Geology (대한지질공학회)
권호 표지
DOI QR코드

DOI QR Code

Formation Identification using Anisotropic Parameters from Sonic and Density Logs

음파검층과 밀도검층 자료에서 산출된 이방성 변수를 이용한 지층 구분

  • Jang, Seonghyung (Korea Institute of Geoscience and Mineral Resources, Petroleum and Marine Division) ;
  • Kim, Tae Youn (Korea Institute of Geoscience and Mineral Resources, Geological Environment Division) ;
  • Hwang, Seho (Korea Institute of Geoscience and Mineral Resources, Geological Environment Division)
  • 장성형 (한국지질자원연구원 석유해저연구본부) ;
  • 김태연 (한국과학기술연합대학원대학교 석유자원공학) ;
  • 황세호 (한국과학기술연합대학원대학교 석유자원공학)
  • Received : 2017.08.31
  • Accepted : 2017.09.28
  • Published : 2017.09.30
Download PDF
⟨ Previous Next ⟩

Abstract

For the formation identification, surface geological survey, drill core analysis, core description and well log analysis are widely used. Among them well log analysis is a popular method with drill core analysis, since it measures continuously physical properties at in-situ. In this study we calculated Thomsen anisotropic parameters (${\varepsilon},\;{\delta},\;{\eta}$) after applying Backus averaging method to the P wave velocity, S wave velocity, and density logs. The well log data application of Blackfoot, Canada, shows the formation could be divided by 12 layers. This shows that Thomsen anisotropic parameters for identifying formation using anisotropic parameters is useful if there is no natural gamma log that is widely used for the formation identification.

지하 지층의 확인은 지표면 지질조사, 시추코어 분석, 시추코어 관찰, 물리검층 자료 분석 등의 다양한 방법을 이용한다. 이 가운데 물리검층 자료는 원위치에서 연속적으로 물성을 제공하므로 시추코어 분석 자료와 더불어 지층의 확인에 활용되고 있다. 본 연구에서는 완전파형 음파검층과 밀도검층 자료에서 이방성 변수를 구하고 이를 이용하여 지층의 구분에 적용하고자 하였다. 톰슨 이방성 변수(${\varepsilon},\;{\delta},\;{\eta}$)는 바쿠스(Backus) 평균법을 P파와 S파 속도, 밀도검층 자료에 적용하여 계산하였다. 이와 같은 방법을 캐나다 블랙풋의 물리검층 자료에 적용한 결과, 12개 구간으로 지층을 구분 할 수 있 수 있었다. 즉, 탄성파 속도 이방성을 반영하는 톰슨 이방성 값의 변화에서 지층의 구분이 가능하였고 지층 구분에 많이 이용하는 자연감마선검층 자료가 없는 경우에도 톰슨 이방성 변수를 이용하여 지층 구분이 가능함을 알 수 있었다.

Keywords

References

  1. Alkhalifah, T. and Tsvankin, I., 1995, Velocity analysis for transversely isotropic media, Geophysics, 60, 1550-1566. https://doi.org/10.1190/1.1443888
  2. Backus, G. E., 1962, Long-wave elastic anisotropy produced by horizontal layering, Journal of Geophysical Research, 67, 4427-4440. https://doi.org/10.1029/JZ067i011p04427
  3. Bayuk, I. O., Ammerman, M., and Chesnokov, E. M., 2007, Elastic moduli of anisotropic clay, Geophysics, 72, D107-D115. https://doi.org/10.1190/1.2757624
  4. Berryman, J. G., 1979, Long-wave elastic anisotropy in transversely isotropic media, Geophysics, 44, 896-917. https://doi.org/10.1190/1.1440984
  5. Berryman, J. G., Grechka, V. Y., and Berge, P. A., 1999, Analysis of Thomsen parameters for finely layered VTI media, Geophysical Prospecting, Vol. 47, pp. 959-978. https://doi.org/10.1046/j.1365-2478.1999.00163.x
  6. Chang, S. K., Everhart, A. H., and Hornby, B., 1984, Full waveform sonic logging in a shale formation: Field data and theoretical waveforms, 54th Annual International Meeting, SEG, Expanded Abstracts, 3-5.
  7. Chapman, M., 2003, Frequency dependent anisotropy due to mesoscale fractures in the presence of equant porosity, Geopysical Prospecting, 51, 369-379. https://doi.org/10.1046/j.1365-2478.2003.00384.x
  8. Debrah, E. A., 2013, Upscaling of well log data for a transversely isotropic effective medium, MSc thesis, Norwegian University of Science and Technology.
  9. Gold, N., Shapiro, S. A., Bojinski, S., and Muller, T. M., 2000, An approach to upscaling for seismic waves in statistically isotropic heterogeneous elastic media, Geophysics, 65, 1837-1850. https://doi.org/10.1190/1.1444867
  10. Jacobsen, K. W., Norskov, J. K., Puska, M. J., 1987, Interatomic interactions in the effective-medium theory, Physical Review B., 35, 7423-7442. https://doi.org/10.1103/PhysRevB.35.7423
  11. Keys, W. S., 1989, Borehole geophysics applied to groundwater investigations, National Water Well Association, 313p.
  12. Kim, Y., Jang, S. I., 1998, Lithology determination by log analysis from a borehole-PABH1 in the Pungam sedimentary Basin, The Journal of Engineering Geology, 8, 163-173 (in Korean with English abstract).
  13. Lee, S. J., Lee, C. H, Jang, H. S., and Kim, J. S., 2011, Physical properties of and joint distribution within the Cheongju granitic mass, as assessed from drill-core and geophysical welllogging data, The Journal of Engineering Geology, 21, 15-24 (in Korean with English abstract). https://doi.org/10.9720/kseg.2011.21.1.015
  14. Liner, C. L. and Fei, T. W., 2006, Layer-induced seismic anisot-ropy from full-wave sonic logs: Theory, application, and validation, Geophysics, 71, D183-D190. https://doi.org/10.1190/1.2356997
  15. Lo, T., Coyner, K., Toksoz, N., 1986, Experimental determination of elastic anisotropy of Berea sandstone, Chicopee shale, and Chelmsford granite, Geophysics, 51, 164-171. https://doi.org/10.1190/1.1442029
  16. Lynn, H. B., 2014, Azimuthal anisotropy: Distinguishing between unequal horizontal stress and vertical aligned macro-fractures, as demonstrated in thirty years of eld data analysis, SEG Technical Program Expanded Abstracts, 473-479.
  17. Mahmoudian, F., Margrave, G. F., Daley, P. F., and Wong, J., 2012, Anisotropy estimation for a simulated fractured medium using traveltime inversion: A physical modeling study, SEG Technical Program Expanded Abstracts, 1-6.
  18. Martnez, J. M. and Schmitt, D. R., 2013, Anisotropic elastic moduli of carbonates and evaporites from the Weyburn- Midale reservoir and seal rocks, Geophysical Prospecting, 61, 363-379. https://doi.org/10.1111/1365-2478.12032
  19. Margrave, G. F., Lawton, D., C. and Stewart, R., R., 1998, Interpreting channel sands with 3C-3D seismic data, The leading edge, 18, 509-513.
  20. Sakai, 1994, Visualization of boreholes soils and foundations, The Japanese Geotechnical Society, 42, 13-18.
  21. Sayers, C. M., 2008, The effect of low aspect ratio pores on the seismic anisotropy of shales, 78th Annual International Meeting, SEG, Extended Abstracts, 2606-2611.
  22. Sinha, S. and Ramkhelawan, R, 2008, P-wave azimuthal anisotropy from a fullwave seismic field trial in Wamsutter, SEG Technical Program Expanded Abstracts 2008, pp. 198-201.
  23. Song, M. Y., Kim, H. S., Park, J. O., 2002, Relationship between lithology and rock physical property using borehole prospecting, The Journal of Engineering Geology, 12, 127-135 (in Korean with English abstract).
  24. Stoneley, R., 1949, The seismological implications of aeolotropy in continental structure: Monthly Notices of the Royal Astronomical Society, Geophysical Supplement, 5, 222-232.
  25. Thomsen, L., 1986, Weak elastic anisotropy, Geophysics, 51, 1954-1966. https://doi.org/10.1190/1.1442051
  26. Wang, Z., 2002, Seismic anisotropy in sedimentary rocks, part 2: Laboratory data, Geophysics, 67, 1423-440. https://doi.org/10.1190/1.1512743
  27. Wood, J. M. and Hopkins, J. C, 1992, Traps associated with paleovalleys and interuves in unconformity bounded sequence: Lower Cretaceous Glauconitic Member, Southern Alberta, Canada, AAPG Bulletin.
  28. Wu, Q., Li, Y., and Li, Z., 2013, Improved subsalt imaging of full azimuth data with tilted orthorhombic PSDM, SEG Technical Program Expanded Abstracts 2013, 3810-3814.