Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-25T15:40:57.908Z Has data issue: false hasContentIssue false
  • English
  • Français

A study of sub-basalt depth imaging using the local Radon attributes on the Erlend Tertiary volcanic complex - North of Shetland, UK#

Published online by Cambridge University Press:  01 April 2016

A. Droujinine ,
J. Pajchel  and
K. Hitchen
A. Droujinine*
Affiliation:
British Geological Survey, West Mains Road, Edinburgh EH9 3LA UK.
J. Pajchel
Affiliation:
Norsk Hydro Research Centre, P.O. Box 7190, Bergen 5020, Norway.
K. Hitchen
Affiliation:
British Geological Survey, West Mains Road, Edinburgh EH9 3LA UK.
*
*Corresponding author.

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Acquiring conventional 3 km towed streamer data along a 2D profile in the North of Shetland (UK) enables us to use the local Radon-attributes within the context of depth processing methodology for accurate delineation of volcanic units and imaging beneath high-velocity layers. The objective is to map the radially-dipping structure of the Erlend pluton and to investigate the potential existence of relatively soft Cretaceous sediments underneath volcanic units. Success in the Erlend Volcano study requires strict attention to the separation between different groups of events. The crucial point is the generalized discrete Radon transform formulated in terms of local wavefront (dip and curvature) characteristics. This transform is utilized during pre-CMP processing and migration to minimize event-coupling artefacts. These artefacts represent cross-talk energy between various wave modes and include the unwanted part of the wavefield. We show how to produce detailed subsurface images within the region of interest (exploration prospect only) by applying the closely tied processes of prestack event enhancement and separation, well-driven time processing for velocity model building, and final event-based prestack depth imaging. Results show enhanced structural detail and good continuity of principal volcanic units and deeper reflections, suggesting a faulted 0.6 – 0.9 km thick layer of Cretaceous sediments in the proximity of well 209/09-1. Our interpretation complements existing low-resolution geophysical models inferred from gravity and wide-angle seismic data alone.

Keywords

Sub-basalt imagingNorth of ShetlandErlend Volcanogeneralized discrete Radon transformlocal moveout attributesmode conversions
Type
Research Article
Information
Netherlands Journal of Geosciences , Volume 87 , Issue 2 , August 2008 , pp. 135 - 149
Copyright
Copyright © Stichting Netherlands Journal of Geosciences 2008

Footnotes

#

Paper presented at the 67th EAGE Conference & Exhibition, Madrid, Spain, 13 - 16 June 2005

References

Barzaghi, L., Calcagni, M., Passolunghi, M. & Sandrani, S., 2002, Faeroe sub-basalt seismic imaging: a new iterative time processing approach. First Break 20: 611–617.Google Scholar
Beylkin, G., 1982, Generalized Radon transform and its application. PhD thesis, New York University (New York).Google Scholar
Castle, R.J., 1994. A theory of normal moveout. Geophysics 59: 983–999.CrossRefGoogle Scholar
Christie, P., Gollifer, I. & Cowper, D., 2002. Borehole seismic results from the Lopra deepening project. Journal of Conference Abstracts 7(2): 138–139.Google Scholar
Dillon, P.B., Ahmed, H. … Roberts, T., 1988. Migration of mixed mode VSP wavefields. Geophysical Prospecting 36: 825–846.CrossRefGoogle Scholar
Draujinine*, A., 2003. Decoupled elastic prestack depth migration. Journal of Applied Geophysics 54: 369–389.Google Scholar
Drovjinine, A.. 2005. The attribute based generalized discrete Radon transform. Journal of Seismic Exploration 14: 155–196.Google Scholar
Fruehn, J., Fliedner, M.M. & White, R.S., 2001. Integrated wide-angle and near-vertical sub-bsalt study using large-aperture seismic data from the Faeroe-Shetland region. Geophysics 66: 1340–1348.CrossRefGoogle Scholar
Gatliff, R.W., Hitchen, K., Ritchie, J.D. & Smythe, D.K., 1984. Internal structure of the Erlend Tertiary volcanic complex, north of Shetland, revealed by seismic reflections. Journal of the Geological Society 141: 555–562.CrossRefGoogle Scholar
Hawkins, K., Leggott, R., Williams, G. … Kat, H., 2001. Addressing anisotropy in 3-D prestack depth migration: A case study from the Southern North Sea. The Leading Edge 20: 528–535.CrossRefGoogle Scholar
Jolley, D.W. & Bell, B.R. 2002, Genesis and age of the Erlend Volcano, NE Atlantic Margin: Geological Society, London, Special Publications 197; 95–110.CrossRefGoogle Scholar
Jones, I.F., 2003. A review of 3D preSDM velocity model building techniques. First Break 21: 45–58.CrossRefGoogle Scholar
Kuo, J.T. … Dai, T.-F., 1984. Kirchhoff elastic wave migration for the case of noncoincident source and receiver. Geophysics 49: 1223–1238.CrossRefGoogle Scholar
Lombaré, G., Herrmann, P., Guillaume, P., Zimine, S., Wolfarth, S., Hermant, O. & Butt, S., 2007. Emm time to depth imaging with ‘Beyond Dix’. First Break 25: 71–76.Google Scholar
Maresh, J. & White, R.S., 2005. Seeing through a glass, darkly: strategies for imaging through basalt. First Break 23: 27–33.CrossRefGoogle Scholar
Martini, F. & Bean, C.J., 2002, Interface scattering versus body scattering in sub-basalt imaging and application of prestack wave equation datuming. Geophysics 67: 1593–1601.CrossRefGoogle Scholar
Ogilvie, J.S., Crompton, R. & Hardy, N.M., 2001. Characterization of volcanic units using detailed velocity analysis in the Atlantic Margin, West of Shetlands, United Kingdom. The Leading Edge 20(1): 34–50.CrossRefGoogle Scholar
Planke, S., Alvestad, E. & Eldholm, O. 1999. Seismic characteristics of basaltic extrusive and intrusive rocks. The Leading Edge 18{3): 342–348.CrossRefGoogle Scholar
Purnell, G.W., 1992. Imaging beneath a high-velocity layer using converted waves. Geophysics 57: 1444–1452.CrossRefGoogle Scholar
Robein, E. & Hanitzsch, C. 2001. Benefits of pre-stack time migration in model building: a case history in the South Caspian Sea. First Break 19: 183–189.CrossRefGoogle Scholar
Spitzer, R., White, R.S. & Chrtetie, P.A.F., 2003. Enhancing sub-basalt reflections using parabolic τ - p transformation. The Leading Edge 22(12): 1184–1201.CrossRefGoogle Scholar
Stoker, M.S., Hitchen, K. & Graham, C.C., 1993. The geology of the Hebrides and West Shetland shelves, and adjacent deep-water areas. HMS0 (London).Google Scholar
Takahashi, T. 1995. Prestack migration using arrival angle information. Geophysics 60: 154–163.CrossRefGoogle Scholar
Tatham, R.H., Goolsbee, D.V., Masseil, W.F. & Nelson, H.R.. 1983. Seismic shear wave observations in a physical model experiment. Geophysics 48: 688–701.CrossRefGoogle Scholar
Thomsen, L., 1986, Weak elastic anisotropy. Geophysics 51: 1954–1956.CrossRefGoogle Scholar
Thomsen, L., 1999. Converted-wave reflection seismology over inhomogeneous, anisotropie media. Geophysics 64: 678–690.CrossRefGoogle Scholar
Van der Baan, M., Kerrane, T., Kendall, J.-M. & Taylor, N., 2003. Imaging sub-basalt structures using locally converted waves. First Break 21: 29–36.CrossRefGoogle Scholar
White, R.E., 1980. Partial coherence matching of synthetic-seismograms with seismic traces. Geophysical Prospecting 28: 333–358.CrossRefGoogle Scholar
Yilmaz, O., 2001. Seismic data analysis. SEG, >Tulsa, OK. Google Scholar