Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
The Leading Edge Don't get GSW? Talk to your librarian.
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
The Leading Edge; January 2001; v. 20; no. 1; p. 34-50; DOI: 10.1190/1.1438874
© 2001 Society of Exploration Geophysicists
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ogilvie, J. S.
Right arrow Articles by Hardy, N. M.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

Characterization of volcanic units using detailed velocity analysis in the Atlantic Margin, West of Shetlands, United Kingdom

Jeffrey S. Ogilvie

Texaco International, Houston, Texas, U.S.

Richard Crompton

Paradigm Geophysical, Slough, U.K.

Nicholas M. Hardy

Texaco Britain Ltd., London, U.K.

Corresponding author: J. S. Ogilvie, ogilvjs@texaco.com

The first 20% of the full text of this article appears below.

The offshore Faroe-Shetlands Basin, northwest of Scotland and south of the Faroe Islands (Figure 1), has seen renewed exploration interest following development of Schiehallion, Foinaven, and Loyal fields and opening of the first licensing round of the Faroe Islands.


Figure Removed (Available Only in the Full Text)
View larger version (153K):
[in this window]
[in a new window]
  		Figure 1. Significant basalt wells, rock property studies, and key velocity inversion profiles in area of study.

 
Interpretation of volcanic data in the area is very challenging, and many local oil and gas prospects involve clastic objectives above or below volcanic zones. High uncertainty about the thickness and morphology of these zones results in high uncertainties in structural geometry, reservoir definition, and hydrocarbon migration and charge risk. Only a few wells have penetrated these volcanic zones to date. Sonic logs from these wells and regional rock property trends for Tertiary-aged clastic sediments suggest that significant rms (root-mean-square) velocity changes occur at or near these volcanic boundaries, boundaries not easily identified with conventional 2-D or 3-D data and interpretation techniques.

This case study discusses how interpretation was improved via a focus on velocity coherence analysis. Data were reprocessed using various demultiple and filtering techniques specifically designed to improve velocity coherence analysis. Emphasis was placed on identification of "bona fide" velocity coherences and associated inflection points within stacking velocities that might indicate "bulk" changes to true interval velocities.


   Background
 
The geology of the Late Cretaceous and Early Tertiary in the vicinity of the Faroe Islands is dominated by incipient continental break-up and associated rifting between Greenland and northwest Europe. This break-up, and its association with a major mantle plume, has created one of the world's major basalt provinces.

The Faroe Islands are predominantly made of these basaltic lavas, intercalated with tuff and relatively minor sedimentary rocks. Faroese lavas are broadly equivalent in age to those encountered in the British Isles, Greenland, and offshore Norway, . . . [Full Text of this Article]






JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2009 by Society of Exploration Geophysicists