A reliable velocity estimation in a complex deep-water environment using downward continued long offset multi-channel seismic (MCS) data

Abstract

The estimation of a reliable velocity–depth model from towed streamer marine seismic data recorded in deep water, especially with a complex seafloor environment, is challenging. The determination of interval velocities from the normal move-out (NMO) of the reflected seismic signals for shallow reflectors (<1 km below the seafloor) is compromised by the combination of a long wave path in the water column and the complex ray paths due to topography, leading to small move-out differences between reflectors. Furthermore, low sediment velocities and deep water produce refraction arrivals only at limited far offsets that contain information about deeper structures. Here, we present an innovative method where towed streamer seismic data are downward continued to the seafloor leading to the collapse of the seafloor reflection and the emergence of refraction events as first arrivals close to zero offset, which are used to determine a high-resolution near surface velocity–depth model using an efficient tomographic method. These velocities are then used to perform pre-stack depth migration. We found that the velocity–depth model derived from tomography of downward continued towed streamer data provides a far superior pre-stack depth migrated image than those produced from velocity–depth models derived from conventional velocity estimation techniques.

Research Highlights

  • A comparison in velocity from conventional NMO, sparsely spaced OBS tomography, and tomography of downward continue streamer data is carried out.

  • Accuracy in velocities are proved from the prestack depth migration results.

This is a preview of subscription content, access via your institution.

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8

References

  1. Arnulf A F, Singh S C, Harding A J, Kent G M and Crawford W 2011 Strong seismic heterogeneity in layer 2A near hydrothermal vents at the Mid-Atlantic Ridge; Geophys. Res. Lett. 38 L13320.

    Article  Google Scholar 

  2. Arnulf A F, Harding A J, Singh S C, Kent G M and Crawford W 2012 Fine-scale velocity structure of layer 2A from full waveform inversion of downward continued seismic reflection data in the Lucky strike volcano, Mid Atlantic Ridge; Geophys. Res. Lett. 39 8.

    Article  Google Scholar 

  3. Berryhill J R 1979 Wave equation datuming; Geophysics 44 1329–1344.

    Article  Google Scholar 

  4. Chauhan A P S, Singh S C, Hananto N D, Carton H, Klingelhoefer F, Dessa J, Permana H, White N J and Graindorge D 2009 Seismic imaging of forearc backthrusts at northern Sumatra subduction zone; Geophys. J. Int. 179 1772–1780.

    Article  Google Scholar 

  5. Chauhan A J 2010 Structure of the Northern Sumatra subduction megathrust using seismic reflection and refraction data, PhD Thesis, Institut de Physique du Globe de Paris.

  6. Claerbout J 1976 Fundamentals of Geophysical Data Processing, http://sepwww.stanford.edu/sep/prof/.

  7. Galloway W E 2008 Depositional evolution of the Gulf of Mexico sedimentary basin; In: The Sedimentary Basins of the United States and Canada, Sedimentary Basins of the World (ed.) Hsu K J, Elsevier, The Netherlands 5 505–549.

  8. Gazdag J 1978 Wave equation migration with the phase shift method; Geophysics 43 1342–1351.

    Article  Google Scholar 

  9. Ghosal D, Singh S C, Chauhan A P S and Hananto N 2012 New insights on the offshore extension of the Great Sumatran fault, NW Sumatra, from marine geophysical studies; Geochem. Geophys. Geosyst. 13, https://doi.org/10.1029/2012GC004122.

  10. Ghosal D, Singh S C and Martin J 2014 Shallow subsurface morphtectonics of the NW offshore northern Sumatra subduction system using an integrated seismic imaging technique; J. Geophys. Res. 198 1818–1831, https://doi.org/10.1093/gji/ggu182.

    Article  Google Scholar 

  11. Fitch T J 1972 Plate convergence, transcurrent faults, and initial deformation adjacent to southeast Asia and the western Pacific; J. Geophys. Res. 77 4432–4460, https://doi.org/10.1029/JB077i023p04432.

    Article  Google Scholar 

  12. Harding A J, Kent G, Blackman D K, Singh S C and Cannales J-P 2007 A new method for MCS refraction data analysis of the uppermost section at a Mid-Atlantic Ridge core complex; EOS, Trans. Am. Geophys. Union 88(52), Fall Meet. Suppl., Abstract S12A-03.

  13. Liu C S, Curray J R and McDonald J M 1983 New constraints on the tectonic evolution of the eastern Indian Ocean; Earth Planet. Sci. Lett. 65 331–342.

    Google Scholar 

  14. McCaffrey R 2009 The tectonic framework of the Sumatra subduction zone; Ann. Rev. Earth Planet. Sci. 37 345–366, https://doi.org/10.1146/annurev.earth.031208.100212.

    Article  Google Scholar 

  15. Matson R and Moore G F 1992 Structural controls on forearc basin subsidence in the central Sumatra forearc basin; Geol. Geophys. Cont. Margins, AAPG Memoir 53 157–181.

    Google Scholar 

  16. Moser T J 1991 Shortest path calculation of seismic rays; Geophysics 56 59–67.

    Article  Google Scholar 

  17. Sheriff R E and Geldart L P 1982 Exploration seismology; volume 1, Cambridge University Press, 253p.

  18. Sieh K and Natawidjaja D 2000 Neotectonic of the Sumatran fault Indonesia; J. Geophys. Res. 105 28,295–28,326, https://doi.org/10.1029/2000JB900120.

    Article  Google Scholar 

  19. Singh S C, Carton H, Tapponnier P, Hananto N, Chauhan A P S, Hartoyo D, Bayly M, Moeljopranoto S, Bunting T, Christie P, Lubis H and Martin J 2008 Seismic evidence for broken oceanic crust in the 2004 Sumatra earthquake epicentral region; Nat. Geosci. 1 771–781.

    Article  Google Scholar 

  20. Singh S C, Chauhan A P S, Calvert A J, Hananto N D, Ghosal D, Rai A and Carton H 2012 Seismic evidence of bending and unbending of subducting oceanic crust and the presence of mantle megathrust in the 2004 Great Sumatra earthquake rupture zone; Earth Planet. Sci. Lett. 321–322 166–176, https://doi.org/10.1016/j.epsl.2012.01.012.

    Article  Google Scholar 

  21. Van Avendonk H J A, Shillington D, Holbrook W S and Hornbach M 2004 Inferring crustal structure in the Aleutian island arc from a sparse wide-angle seismic data set; Geochem. Geophys. Geosyst. 5(8) 1527–2087.

    Google Scholar 

  22. Yelisetti S, Spense G D and Riedel M 2014 Role of gas hydrate in slope failure of frontal ridge of northern Cascadia margin; Geophys. J. Int. 199(1) 441–458, https://doi.org/10.1093/gji/ggu254.

    Article  Google Scholar 

Download references

Acknowledgements

We are thankful to J Martin, A Harding, N Bangs, A Chauhan, H Carton and N D Hananto for their support during this study. We are grateful to Western Geco for carrying out the survey for us.

Author information

Affiliations

Authors

Contributions

Dibakar Ghosal contributed in writing, generating figures and editing. Satish Singh contributed in providing datasets and supervising the project.

Corresponding author

Correspondence to Dibakar Ghosal.

Additional information

Communicated by Arkoprovo Biswas

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Ghosal, D., Singh, S.C. A reliable velocity estimation in a complex deep-water environment using downward continued long offset multi-channel seismic (MCS) data. J Earth Syst Sci 130, 44 (2021). https://doi.org/10.1007/s12040-020-01531-9

Download citation

Keywords

  • Downward continuation
  • tomography
  • pre-stack depth migration
  • OBS
  • MCS