1887

Abstract

Summary

FWI to extract velocity models has been successfully applied in shallow-water environments by exploiting refracted and turning wave information. In deep-water environments with a limited recorded offset length (∼10 km), FWI is more challenging due to there being less refracted energy to control the inversion process. We demonstrate the applicability of acoustic FWI method in a deep-water environment with towed streamer seismic data, acquired in the Orange Basin, South Africa. To do this, we use a highly accurate traveltime tomographic image ( ) as a starting model, and we initially invert the very lowest frequency components in order to mitigate the non-linearity issue. We applied a variety of strategies of data pre-processing, pre-conditioning, wavenumber filtering, and re-estimating the source signatures to optimize the FWI results. The inverted velocity model was validated by a comparison of the observed and predicted waveforms. The kinematics of the predicted wavefield shows a reasonably good agreement with the observed waveform as well as a good correlation with the velocity image corresponding to the reflector on the PSDM seismic image. Further advances are anticipated to incorporate amplitude information with higher frequencies >6.0 Hz, in order to investigate the attenuation effects within the modelled space.

Loading

Article metrics loading...

/content/papers/10.3997/2214-4609.201801575
2018-06-11
2024-03-29
Loading full text...

Full text loading...

References

  1. Brenders, A. and Pratt, R.
    2007. Full waveform tomography for lithospheric imaging: Results from a blind test in a realistic crustal model. Geophysical Journal International. 168(1), pp.133–151.
    [Google Scholar]
  2. Elboth, T., Reif, B. and Andreassen, O.
    2009. Flow and swell noise in marine seismic: Geophysics, 74. Q17–Q25.
    [Google Scholar]
  3. Jelani, M. and Booth, A.
    2017. Seismic Tomography Velocity Modelling of Seaward Dipping Reflectors in the Orange Basin, Off Namibia Field, South Africa. In: 79th EAGE Conference and Exhibition2017.
    [Google Scholar]
  4. Kamei, R., Pratt, R. and Tsuji, T.
    2013. On acoustic waveform tomography of wide-angle OBS data—strategies for pre-conditioning and inversion. Geophysical Journal International. 194(2), pp.1250–1280.
    [Google Scholar]
  5. Pratt, R.G.
    1990. Inverse theory applied to multi-source cross-hole tomography. Geophysical Prospecting. 38(3), pp.311–329.
    [Google Scholar]
  6. 1999. Seismic waveform inversion in the frequency domain, Part 1: Theory and verification in a physical scale model. Geophysics. 64(3), pp.888–901.
    [Google Scholar]
  7. Pratt, R.G., Shin, C. and Hick, G.
    1998. Gauss–Newton and full Newton methods in frequency–space seismic waveform inversion. Geophysical Journal International. 133(2), pp.341–362.
    [Google Scholar]
  8. Sirgue, L. and Pratt, R.G.
    2004. Efficient waveform inversion and imaging: A strategy for selecting temporal frequencies. Geophysics. 69(1), pp.231–248.
    [Google Scholar]
  9. Zelt, C.A. and Barton, P.J.
    1998.Three-dimensional seismic refraction tomography: A comparison of two methods applied to data from the Faeroe Basin. Journal of Geophysical Research: Solid Earth (1978–2012). 103(B4), pp.7187–7210.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/papers/10.3997/2214-4609.201801575
Loading
/content/papers/10.3997/2214-4609.201801575
Loading

Data & Media loading...

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