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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.
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Abstract

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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

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