Print Email Facebook Twitter Inversion of multi-transient EM data from anisotropic media Title Inversion of multi-transient EM data from anisotropic media Author Werthmüller, D. Contributor Hobbs, B.A. (mentor) Ziolkowski, A. (mentor) Slob, E.C. (mentor) Faculty Civil Engineering and Geosciences Department Geotechnology Programme Applied Geophysics Date 2009-08-25 Abstract Forward modelling demonstrates that resistivity anisotropy has a huge effect on Multi-Transient ElectroMagnetic step and impulse responses. The earth is never isotropic – even a stack of isotropic layers behaves anisotropically – and there is a great need to ccount for resistivity anisotropy in order to delineate the true target depth and target transverse resistance in ElectroMagnetic surveying. I account for resistivity anisotropy by (a) deriving apparent anisotropy formulae and using them together with apparent resistivities for a fast iterative inversion scheme, and (b) by including anisotropy into a 1D full waveform inversion scheme. Full anisotropic inversions result in much smoother models than isotropic inversions. Sharp resistivity boundaries result in anisotropy anomalies, as horizontal and vertical resistivities are not affected in the same way. Anisotropic inversion results yield a good indication of the present background anisotropy. Carrying out inversions with fixed anisotropies, e.g. determined in a free anisotropic inversion, can improve the result significantly compared with an isotropic inversion. Subject CSEMTransientAnisotropyInversion To reference this document use: http://resolver.tudelft.nl/uuid:f4b071c1-8e55-4ec5-86c6-a2d54c3eda5a Part of collection Student theses Document type master thesis Rights (c) 2009 Werthmüller, D. Files PDF 09msc_dw_anisoinvmtem_FINAL.pdf 1.88 MB Close viewer /islandora/object/uuid:f4b071c1-8e55-4ec5-86c6-a2d54c3eda5a/datastream/OBJ/view