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Enhancing 3-D seismic images of deep and complex structures

Objective



The proposal "3D FOCUS" addresses the introduction of new technologies foreseen to allowfor significant enhancements in seismic images of complex geological structures.

In the last decade, the shift from 2D to 3D seismic acquisition opened new possibilities for exploration, delineation and eventual exploitation of small, marginal reservoirs in complex geological environments. This is of particular concern for companies operating in the North Sea. In the current industrial practice, such data are still prominently processed in the time domain, with geometric approximations no more valid in complex media. Recent testcases on complex 3D structures demonstrated the potential benefits of seismic imaging in depth (prestack depth migration) Yet, for imaging in depth to become a generalized practice, improvements in efficiency and precision are required at several stages of the whole processing sequence.
A first, major objective of the project is devoted to seismic imaging in depth.

Two complementary tasks will address :

- the development of technologies designed to decrease (but not suppress) the need for human expertise and intervention in the iterative building of a velocity model optimized in terms of image focusing;

- the development of a 3D prestack depth migration algorithm accounting for the expected st uctural complexity of rayfields (multipathing, triplications) when large scale complex geological structures are present.
Although depth imaging will eventually become a routine practice in the industry, it is generally believed that seismic imaging in the time domain will continue to play a significant part as a complementary process. A second, minor objective will thus focus onto improving time imaging with the help of the concepts of homeomorphic imaging. These concepts will allow the use of less stringent geometric approximations than the ones presently underlying time migration.

The third, major obJective will be an industry-lead assessment of the technologies developed in the previous objectives via tests against two 3D datasets acquired in the North Sea. One addresses a very difficult imaging problem (tilted blocks beneath a salt ridge), while the other seeks enhancements in resolution of seismic images of a complex, faulted reservoir for reservoir engineering purposes. The overall objective of the project is thus to provide new prototype methodologies together with their actual assessment on two real, challenging industrial problems.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Association pour la Recherche et le Développement des Méthodes et ProcessusIndustriels - ARMINES
Address
Rue Saint-honoré
77305 Fontainebleau
France

Participants (5)

Elf Exploration Production S.A.
France
Address
Avenue Larribau
64000 Pau
Norsk Hydro ASA
Norway
Address
90,Sandsliveien
5020 Bergen
The Geophysical Institute of Israel
Israel
Address
1,Hamashbir Street
58122 Holon
UNIVERSITY OF HAMBURG
Germany
Address
Bundesstrasse 55
20146 Hamburg
University of Cambridge
United Kingdom
Address
Downing Street
CB2 3EQ Cambridge