Fast numerical methods for marine controlled-source electromagnetic (EM) survey data based on multigrid quasi-linear approximation and iterative EM migration*
Takumi Ueda 1 3 Michael S. Zhdanov 21 Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST) Central 7 Higashi 1-1-1, Tsukuba, Ibaraki 305-8567, Japan.
2 Department of Geology and Geophysics, University of Utah, 135 S. 1460 E., Room 719, Salt Lake City, UT 84112-0111, USA.
3 Corresponding author. Email: takumi.ueda@aist.go.jp
Exploration Geophysics 39(1) 60-67 https://doi.org/10.1071/EG08002
Submitted: 10 August 2007 Accepted: 31 October 2007 Published: 5 March 2008
Abstract
In this paper we consider an application of the method of electromagnetic (EM) migration to the interpretation of a typical marine controlled-source (MCSEM) survey consisting of a set of sea-bottom receivers and a moving electrical bipole transmitter. Three-dimensional interpretation of MCSEM data is a very challenging problem because of the enormous number of computations required in the case of the multi-transmitter and multi-receiver data acquisition systems used in these surveys. At the same time, we demonstrate that the MCSEM surveys with their dense system of transmitters and receivers are extremely well suited for application of the migration method. In order to speed up the computation of the migration field, we apply a fast form of integral equation (IE) solution based on the multigrid quasi-linear (MGQL) approximation which we have developed. The principles of migration imaging formulated in this paper are tested on a typical model of a sea-bottom petroleum reservoir.
Key words: electromagnetic method, marine CSEM, integral equation, quasi-linear approximation, electromagnetic migration, numerical method, inverse problem.
Acknowledgments
The authors are thankful for the support of the Consortium for Electromagnetic Modelling and Inversion (CEMI), which includes BAE Systems, Baker Atlas Logging Services, BGP China National Petroleum Corporation, BHP Billiton World Exploration Inc., British Petroleum, Centre for Integrated Petroleum Research, EMGS, ENI S. p. A., ExxonMobil Upstream Research Co., INCO Exploration, Information Systems Laboratories, MTEM, Newmont Mining Co., Norsk Hydro, OHM, Petrobras, Rio Tinto - Kennecott, Rocksource, Russian Research Center Kurchatov Institute, Schlumberger, Shell International Exploration and Production Inc., Statoil, Sumitomo Metal Mining Co., and Zonge Engineering and Research Organization.
One of the authors (T.U.) thanks Dr T. Uchida, Dr Y. Mitsuhata, and Dr T. Yokota of the Geological Survey of Japan, AIST, for their continuous support for this paper and advice on electromagnetic exploration methods and marine EM surveys.
Constable, S., and Srnka, L. J., 2007, An introduction to marine controlled-source electromagnetic methods for hydrocarbon exploration: Geophysics 72, WA3–WA12.
| Crossref | GoogleScholarGoogle Scholar |
Portniaguine, O., and Zhdanov, M. S., 1999, Focusing geophysical inversion images: Geophysics 64, 874–887.
| Crossref | GoogleScholarGoogle Scholar |
Zhdanov, M. S., and Frenkel, M. A., 1983a, The solution of the inverse problems on the basis of the analytical continuation of the transient electromagnetic field in reverse time: Journal of Geomagnetism and Geoelectricity 35, 747–765.
Zhdanov, M. S., and Fang, S., 1996, Quasi-linear approximation in 3D EM modelling: Geophysics 61, 646–665.
| Crossref | GoogleScholarGoogle Scholar |
Zhdanov, M. S., Traynin, P., and Booker, J., 1996, Underground imaging by frequency domain electromagnetic migration: Geophysics 61, 666–682.
| Crossref | GoogleScholarGoogle Scholar |
Zhdanov, M. S., and Traynin, P., 1997, Migration versus inversion in electromagnetic imaging technique: Journal of Geomagnetism and Geoelectricity 49, 1415–1437.
*Part of this paper was presented at the 116th SEGJ Conference, 2007.