1887
  1. Home
  2. A-Z Publications
  3. Geophysical Prospecting
  4. Volume 36, Issue 3
  5. Article
Volume 36 Number 3
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

The detection and resolution of a thin layer closely situated above a high‐impedance basement are predominantly determined by both the frequency content of the incident seismic wavelet and the existence of the nearby high‐impedance bedrock.

The separation of the thin layer and the basement arrivals is investigated depending on the low‐frequency content of the wavelet. The high‐frequency content of the wavelet is kept constant. The initial wavelet spectrum with low frequencies has a rectangular shape. All wavelets used have zero‐phase characteristics. Numerical and analogue seismic modelling techniques are used. The study is based on the geology of the Pachangchi Sandstone in West Taiwan.

Firstly the resolution of a thin layer between two half‐spaces is examined by applying the Ricker and De Voogd‐Den Rooijen criteria. The lack of low‐frequency components of the incident seismic wavelet reduces the shortest true two‐way traveltime by about 20%. In addition, low‐frequency components of the wavelet diminish the deviation between true and apparent two‐way traveltime by about 65% for layer thicknesses in the transition from a thick to a thin layer.

The second step deals with the influence of a high‐impedance basement just below a thin layer on the detection and resolution of that thin layer. Reflected signal energies and apparent two‐way traveltimes are considered. The reflected signal energy depends on the low‐frequency content of the incident wavelet, the layer's thickness and the distance between the basement and the layer. This applies only to layers with thicknesses less than or equal to one‐third of the mean wavelength in the layer, and a distance to basement in the range of one to one‐half of the mean wavelength in the rock material between layer and basement.

The minimum thin‐layer thickness resolvable decreases with increasing distance to the basement; i.e. for a layer thickness of one‐third of the mean wavelength in the layer the relative error of the two‐way traveltime increases from 5% to 30%, if the distance is reduced from one to one‐half of the mean wavelength in the material between the basement and the thin layer.

Finally, a combination of vertical seismic profiling and downward‐continuation techniques is presented as a preprocessing procedure to prepare realistic data for the detection and resolution investigation.

Loading

Article metrics loading...

/content/journals/10.1111/j.1365-2478.1988.tb02162.x
2006-04-27
2024-04-18

  • From This Site

    /content/journals/10.1111/j.1365-2478.1988.tb02162.x
    dcterms_title,dcterms_subject,pub_keyword
    -contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution
    10
    5
Loading full text...

Full text loading...

References

  1. AMINZADEH, F. and MENDEL, J. M.1983. Normal incidence layered system state‐space models which include absorption effects. Geophysics48, 259–271.
    [Google Scholar]
  2. AMINZADEH, F. and MENDEL, J. M.1985. Synthetic vertical seismic profiles for nonnormal incidence plane waves. Geophysics50, 127–141.
    [Google Scholar]
  3. BEHRENS, J. and DRESEN, L.1982. Zwei‐ und dreidimensionale analoge modellseismische Untersuchungen‐Interpretationshilfe bei der Erkundung von Lagerstättenstrukturen. In: Modellverfahren bei der Interpretation seismischer Daten, Vol. 2‐2. Mintrop‐Seminar, W.Budach , L.Dresen , J.Fertig and H.Rüter (eds), 295–432. Unikontakt , Ruhr‐Universität Bochum.
    [Google Scholar]
  4. BEHRENS, J. and WANIEK, L.1972. Modellseismik (model seismology). Journal of Geophysics38, 1–44.
    [Google Scholar]
  5. DE VOOGD, N. and DEN ROOIJEN, H1983. Thin‐layer response and spectral bandwidth. Geophysics48, 12–18.
    [Google Scholar]
  6. DRESEN, L. and FREYSTÄTTER, S.1976. Rayleigh channel waves for the in‐seam seismic detection of discontinuities. Journal of Geophysics42, 111–129.
    [Google Scholar]
  7. FERBER, R.1985. Normal‐incidence wavefield computation using vector‐arithmetic. Geophysical Prospecting33, 540–542.
    [Google Scholar]
  8. FERBER, R.1986. Berechnung der zeitlichen Entwicklung der Felder transienter Wellen in geschichteten Medien. Berichte des Instituts für Geophysik, Ruhr‐Universität Bochum, Reihe A, Nr. 19.
    [Google Scholar]
  9. FREYSTÄTTER, S. and DRESEN, L.1978. The influence of obliquely dipping discontinuities on the use of Rayleigh channel waves for the in‐seam seismic reflection method. Geophysical Prospecting26, 1–15.
    [Google Scholar]
  10. KALLWEIT, R. S. and WOOD, L. C.1982. The limits of resolution of zero‐phase‐wavelets. Geophysics47, 1035–1046.
    [Google Scholar]
  11. KOEFOED, O.1981. Aspects of vertical seismic resolution. Geophysical Prospecting29, 21–30.
    [Google Scholar]
  12. KOEFOED, O. and DE VOOGD, N1980. The linear properties of thin layers, with an application to synthetic seismograms over coal seams. Geophysics45, 1254–1268.
    [Google Scholar]
  13. MARANGAKIS, A., COSTAIN, J. K. and CORUH, C.1985. Use of integrated energy spectra for thin‐layer recognition. Geophysics50, 495–500.
    [Google Scholar]
  14. MECKEL, L. D. and NATH, A. K.1977. Geologic considerations for stratigraphic modeling and interpretation, American Association of Petroleum Geologists Special Memoir26, 417–438.
    [Google Scholar]
  15. MEISTER, J.1985. Möglichkeiten und Grenzen hybriden seismischen Modellierens. Berichte des Instituts für Geophysik, Ruhr‐Universität Bochum, Reihe A, Nr. 18.
    [Google Scholar]
  16. MEISTER, J. and DRESEN, L.1987. Hybrid seismic modelling: a technique of combining physical and computer methods for vertical wave incidence. Geophysical Prospecting35, 815–831.
    [Google Scholar]
  17. MENDEL, J. M., NAHI, N.E. and CHAN, M.1979. Synthetic seismograms using the state‐space approach. Geophysics44, 880–895.
    [Google Scholar]
  18. NEIDELL, N. S. and POGGIAGLIOLMI, E.1977. Stratigraphic modeling and interpretation–Geophysical principals and techniques. American Association of Petroleum Geologists Special Memoir26, 389–416.
    [Google Scholar]
  19. O'BRIEN, P. N. S. and SYMES, M.P.1971. Model seismology. Reports on Progress in Physics34, 697–764.
    [Google Scholar]
  20. RICKER, N.1953. Wavelet contraction, wavelet expansion, and the control of seismic resolution. Geophysics18, 769–792.
    [Google Scholar]
  21. ROBERTSON, J. D. and NOGAMI, H. H.1984. Complex seismic trace analysis of thin beds. Geophysics49, 344–352.
    [Google Scholar]
  22. SCHOENBERGER, M.1974. Resolution comparison of minimum‐phase and zero‐phase signals. Geophysics39, 826–833.
    [Google Scholar]
  23. SCHRAMM, M. W., DEDMAN, E. V. and LINDSEY, J. P.1977. Practical stratigraphic modeling and interpretation. American Association of Petroleum Geologists Special Memoir26, 477–502.
    [Google Scholar]
  24. SHERIFF, R. E. and GELDARD, L. P.1983. Exploration Seismology, Data‐Processing and Interpretation, Vol. 2. Cambridge University Press.
    [Google Scholar]
  25. WIDESS, M. B.1973. How thin is a thin bedGeophysics38, 1176–1180.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journals/10.1111/j.1365-2478.1988.tb02162.x
Loading
  • Article Type: Research Article

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error