HR: 16:45h
AN: GP14A-03    [Abstracts]
TI: Three-dimensional MT Modeling and Inversion for Offshore Petroleum Exploration
AU: * Zhdanov, M S
EM: mzhdanov@mines.utah.edu
AF: University of Utah, 135 South 1460 East, Rm 719, Salt Lake City, UT 84112 United States
AU: Wan, L
EM: lwan@mines.utah.edu
AF: University of Utah, 135 South 1460 East, Rm 719, Salt Lake City, UT 84112 United States
AU: Constable, S
EM: sconstable@ucsd.edu
AF: Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093 United States
AU: Key, K
EM: kkey@ucsd.edu
AF: Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093 United States
AB: There is growing interest in the application of marine magnetotelluric (MT) methods for offshore petroleum exploration (Constable et al., 1998; Hoversten et al., 2000). However, until recently, the interpretation of the sea-bottom MT data was performed mostly by two-dimensional (2-D) modeling and inversion methods (de Groot Hedlin and Constable, 1990, 2004). At the same time, the typical sea-bottom geological structures, such as salt domes or petroleum reservoirs, are three-dimensional (3-D). In this paper, we use for 3-D marine MT inversion a new algorithm, which is based on an application of the quasi-analytical (QA) approximation in the initial stage of the iterative inversion, and of the rigorous integral equation forward modeling in the final stage of the inversion. We present the results of numerical modeling and inversion for the typical models of offshore sea-bottom petroleum reservoir in the presence of a salt dome structure. We also consider a case history of 3-D inversion of sea-bottom MT data collected by the Scripps Institution of Oceanography in Gemini Prospect, Gulf of Mexico. The obtained 3-D inverse model correlates reasonably well with the location and shape of the salt dome structure known from the seismic exploration data. This result demonstrates that 3-D inversion method can be used for interpretation of the sea-bottom MT data for offshore exploration.
DE: 3005 Geomagnetism (1550)
DE: 3260 Inverse theory
DE: 0644 Numerical methods
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2004 AGU Fall Meeting