Forward modelling fluid flow using 2-dimensional electrical anisotropy

Abstract

Forward Modelling Fluid Flow using 2-Dimensional Electrical Anisotropy Jake Macfarlane(1), Stephan Thiel(1), Josef Pek(2), Jared Peacock(3), Graham Heinson(1) 1. University of Adelaide, Adelaide, Australia 2. Institute of Geophysics AS CR, Prague, Czech Republic 3. USGS, CA, USA Electrical anisotropy, defined as the directional dependence of electrical conductivity within a medium, causes changes in the electromagnetic signal measured by magnetotellurics (MT) and as such is an important property to consider when interpreting MT data. This study concentrated on replicating the MT response measured at two distinctively different geological settings using a series of 2-dimensional anisotropic forward models. Results presented in this study show that 2-dimensional anisotropic forward modelling is able to account for subtle differences in subsurface anisotropic resistivity structures. Specifically, 2-dimensional anisotropic forward modelling is able to reproduce the measured difference in MT response between pre- and post-fluid injection conditions at the Paralana Geothermal System using an anisotropic fluid volume. These findings provide a case supporting the use of 2-dimensional anisotropic forward modelling as a means of modelling changes caused by the flow of a fluid through the crust.