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Abstract

Summary

Multiphysics approaches to geophysical interpretation that combine seismic data with non-seismic information from electromagnetic surveys can improve the robustness of sub-surface characterisation in exploration and appraisal settings. There is a large database of controlled source electromagnetic (CSEM) and magnetotelluric (MT) data from offshore Sabah and Sarawak in Malaysia that has been used for both regional understanding and prospect-level characterisation. CSEM and MT methods are sensitive to the electrical resistivity of the sub-surface and most of the data analysis conducted so far in Malaysia has assumed vertical transverse isotropy (VTI), in which two resistivity values are defined: the horizontal resistivity which does not vary with azimuth, and the vertical resistivity which is usually higher. This approximation works well in relatively flat lying sediments; however, in dipping sediments, more accurate results are obtained if we assume tilted transverse isotropy (TTI) where the resistivity is defined as bed-parallel (transverse resistivity) and bed-perpendicular (normal resistivity), following stratigraphy. In this paper, we introduce our approach to the inversion of CSEM and/or MT data in TTI media, which builds on our previous work using seismic-guided inversion. We illustrate this with synthetic examples representative of the geological settings encountered in Sabah and Sarawak.

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/content/papers/10.3997/2214-4609.202477271
2024-11-20
2026-02-08

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/content/papers/10.3997/2214-4609.202477271
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Seismic Image-Guided TTI Anisotropic Inversion of Marine Electromagnetic data Offshore Malaysia
Conference Proceedings 2024, 1 (2024); https://doi.org/10.3997/2214-4609.202477271
/content/papers/10.3997/2214-4609.202477271
/content/papers/10.3997/2214-4609.202477271
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