Seismic Traveltime Tomography in Inhomogeneous Tilted Transversely Isotropic Media

불균질 횡등방성 매질에서의 탄성파 주시토모그래피

  • Published : 2007.11.30

Abstract

In this study, seismic anisotropic tomography algorithm was developed for imaging the seismic velocity anisotropy of the subsurface. This algorithm includes several inversion schemes in order to make the inversion process stable and robust. First of all, the set of the inversion parameters is limited to one slowness, two ratios of slowness and one direction of the anisotropy symmetric axis. The ranges of the inversion parameters are localized by the pseudobeta transform to obtain the reasonable inversion results and the inversion constraints are controlled efficiently by ACB(Active Constraint Balancing) method. Especially, the inversion using the Fresnel volume is applied to the anisotropic tomography and it can make the anisotropic tomography more stable than ray tomography as it widens the propagation angle coverage. The algorithm of anisotropic tomography is verified through the numerical experiments. And, it is applied to the real field data measured at limestone region and the results are discussed with the drill log and geological survey data. The anisotropic tomography algorithm will be able to provide the useful tool to evaluate and understand the geological structure of the subsurface more reasonably with the anisotropic characteristics.

References

  1. 이명종, 2000, 전기비저항 탐사 자료를 이용한 지하구조의 3차 원 영상화, 공학 박사 학위 논문, 서울대학교
  2. Byun, B. S., Corrigan, D., and Gaiser, J. E., 1989, Anisotropic velocity analysis for lithology discrimination, Geophysics, 54, 1564-1574 https://doi.org/10.1190/1.1442624
  3. Cerveny, V., and Soars, J. E. P., 1992, Fresnel volume ray tracing, Geophysics, 57, 902-915 https://doi.org/10.1190/1.1443303
  4. Cho, S. J., and Kim, J. H., 1997, Radar traveltime tomography in anisotropic media - in the application of limestone area, EAGE, 59th Conference and Technical Exhibition
  5. Christoffel, E. B., 1877, Über die Fortpflanzung von Stössen durch elastische feste Körper, Annali di Mathematica, 8, 193-243 https://doi.org/10.1007/BF02420789
  6. Cosma, C., Heillkinen, P., Keskinen, K., and Korhonen, R., 1991, Site characterization and validation-Result from seismic crosshole and reflection measurements, Stage 3. Strpa Project Technical Report, '91-07
  7. Eppstein, M. J., Dougherty, D. E., Hawrysz, D. J., and Sevick- Muraca, E. M., 2001, Three-Dimensional Bayesian Optical Image Reconstruction with Domain Decomposition, IEEE Trans. Med. Imag., v.20, 147-163 https://doi.org/10.1109/42.918467
  8. Kelvin, Lord (William Thompson), 1856, On stresses and strains (XXI. Elements of a mathematical theory of elasticity, Part 1), Philosophical Transactions of The Royal Society, 166, 481-489
  9. Kumar, D., Sen, M., and Ferguson, R. J., 2004, Traveltime calculation and prestack depth migration in tilted transversely isotropic media, Geophysics, 69, 37-44 https://doi.org/10.1190/1.1649373
  10. Pratt, R. G., and Chapman, C. H., 1992, Traveltime tomography in anisotropic media-II. Application, Geophys. J. Int., 109, 20-37 https://doi.org/10.1111/j.1365-246X.1992.tb00076.x
  11. Thomsen, L., 1986, Weak elastic anisotropy, Geophysics, 51, 1954-1966 https://doi.org/10.1190/1.1442051
  12. Watanabe, T., Hirai, T., and Sassa, K., 1996, Seismic traveltime tomography in anisotropic heterogeneous media, Journal of Applied Geophysics, 35, 133-143 https://doi.org/10.1016/0926-9851(96)00014-6
  13. Watanabe, T., Matsuoka, T., and Ashida, Y., 1999, Seismic traveltime tomography using Fresnel volume approach, Proc. SEG. Expanded Abstracts
  14. Yanagidani, T., Yamada, H., and Terada, M., 1986, The observation of water infiltration into rock by seismic computer tomography, Proc. JSCE, 370, 169-178