  Faults and geological barriers can drastically affect the flow patterns in
porous media. Such fractures can be modeled as interfaces that interact with
the surrounding matrix. We propose a new technique for the estimation of the
location and hydrogeological properties of a small number of large fractures in
a porous medium from given distributed pressure or flow data. At each
iteration, the algorithm builds a short list of candidates by comparing
fracture indicators. These indicators quantify at the first order the decrease
of a data misfit function; they are cheap to compute. Then, the best candidate
is picked up by minimization of the objective function for each candidate.
Optimally driven by the fit to the data, the approach has the great advantage
of not requiring remeshing, nor shape derivation. The stability of the
algorithm is shown on a series of numerical examples representative of typical
situations.
