Electrical resistivity structures and their relation to geological features at the Larderello geothermal field (Italy)

In this paper Magnetotelluric data were used to investigate the electrical resistivity structures of the Larderello-Travale geothermal system (LTGS) in southern Tuscany, Italy. MT data acquired by ENEL (Italian power company) in the '90 were re-analysed and two-dimensional inversions were performed along a E-W profile crossing the LTGS. The near surface inhomogeneity effects have been reduced by means of tensor decomposition and inversion for static shift. The integration of geological, geophysical and well data was performed in a three-dimensional environment (Petrel, Schlumberger) in order to improve the 2D MT inversion by setting a well-constrained a-priori model and to check inversion results supporting the interpretation. Despite the lithological features, it was clear that an important reduction of the electrical resistivity was required in the crystalline basement to fit experimental data. The results of the MT inversion along the profile have been compared with available public geophysical data.