Multioffset VSP for the integrated geophysical characterization of the Grado (NE Italy) carbonatic reservoir

We present the results of a multi-offset vertical seismic profile (VSP) acquired in the Grado-1 (North Eastern Italy) geothermal exploration well in the framework of an integrated VSP, seismic and gravimetric survey. The purpose of the VSP survey was to link borehole logs and seismic data, and to calibrate the surface seismic data acquired for imaging purposes in the area surrounding the well. The VSP allowed us to obtain high-resolution seismic information in depth, and to measure the variations of the physical rock properties in the fractured carbonatic formations at lateral positions, by means of multi offset data processing and wavefield analysis including anisotropy and Vp/Vs ratio. The VSP provided additional and robust geophysical information for the numerical estimation of the fluid-dynamic modelling of the geothermal-doublet system. The results have been subsequently used for the location of the second well that will be drilled in the geothermal reservoir.