We present 1D anisotropic inversion of magnetotelluric (MT) data as a new and innovative tool for mapping structural permeability in sedimentary basins. Using 1D inversions of a 171 site, broadband MT data set from the Koroit region, Victoria, Australia, we have delineated an electrically anisotropic layer at approximately 2.5 to 3.5 km depth. The anisotropy strike is consistent between stations at approximately 160°. The depth of anisotropy corresponds to the top of the Early Cretaceous Crayfish Group, and the anisotropy factor increases from west to east. We interpret the north-northwest oriented anisotropy as being fluid-filled fractures resulting in enhanced electrical and hydraulic conductivity. This interpretation is consistent with both data from well formation tests and structure and stress field information from the surrounding region.
AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015