f INFORMED INVERSION APPROACH TO ELECTRICAL RESISTIVITY IMAGING IN A FRACTURED-ROCK SETTING

Characterization of fractured rock presents unique inversion challenges in electrical resistivity imaging (ERI). The standard, smoothness-constrained inversion assumptions cannot adequately account for discrete fractures. Similarly, a borehole boundary is a sharp physical contrast and is often a conductive conduit that is typically not adequately incorporated into the inversion. We conducted synthetic studies to examine alternative ERI model parameterization approaches to better represent a fractured rock setting. An unstructured tetrahedral mesh was used for the forward modeling in order to optimize flexibility in the incorporation of boreholes and known fracture locations. Modeling such small-scale features at the plot scale resulted in a finite element mesh with a large number of tetrahedral elements.