HR: 16:00h
AN: GP12B-01    [PDF]
TI: Three-dimensional inversion of marine magnetotelluric data
AU: * Zhdanov, M S
EM: mzhdanov@mines.utah.edu
AF: University of Utah, Department of Geology and Geophysics 1460 E, 135 S, Rm 719, Salt Lake City, UT 84112 United States
AU: Wan, L
EM: lwan@mines.utah.edu
AF: University of Utah, Department of Geology and Geophysics 1460 E, 135 S, Rm 719, Salt Lake City, UT 84112 United States
AB: In this paper we present the results of the feasibility study of the sea-bottom array MT observations for petroleum exploration. We consider a model of an offshore sea-bottom petroleum reservoir. The resistivity of petroleum reservoir and of salt structures is usually on an order greater than those of surrounding sea-bottom sediments. That is why these structures can be considered easily detectable targets for marine MT methods. However, the interpretation of the sea-bottom MT data was based, as a rule, on 1-D or 2-D modeling. Recently, we have developed a powerful 3-D MT inversion method, which can be applied for both the ground and sea-bottom observations. This method is based on an application of the quasi-analytical (QA) approximation in the initial stage of the iterative process to speed up the inversion. However, in the final stage of the inversion we use the rigorous forward modeling to generate more accurate result. We examine several models, which represent a petroleum reservoir in the presence of a salt dome of a complex shape. The inversion results show that even in the case of complex sea-bottom geological structures, where the reservoir response is strongly distorted by the salt dome effect, the inversion generates a clear image of the reservoir. These results demonstrate that the sea-bottom MT survey can be a powerful tool for offshore petroleum exploration.
DE: 0600 ELECTROMAGNETICS
DE: 3005 Geomagnetism (1550)
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2003 Fall Meeting