Inversion of synthetic Electrical Resistivity Tomography experiments for
the characterization of fractured rocks
Abstract
Electrical Resistivity Tomography (ERT) experiments are widely used for
characterizing the natural environment because they easily provide a
large number of data on a large extent and at various depths. These
experiments are usually interpreted with forward models and inversion
strategies that are well suited for equivalent porous medium
representations. Dealing with fractured rocks requires using specific
forward models, which are able to simulate the propagation of electric
current flow in fracture networks that are embedded in conductive
matrix-rock. Although such models have been recently developed, their
integration into inversion strategies, and the definition of the
inversion framework are still challenging. Here, we will start by
showing how simple cases such as a single horizontal and vertical
fracture can be handled by assuming the fracture position as known and
inverting the fracture connectivity. We will then extend this to a
regular network of fracture segments and will analyze various metrics of
the inversion procedure, such as the convergence rate, resolution and
depth of investigation. We will also discuss how defining prior
information to improve the stochastic inversion strategy and future
coupling with other characterization methods.