Seismic Velocity Uncertainties and their Effect on Geothermal Predictions: A Case Study

Geothermal exploration relies in large parts on subsurface models derived from seismic reflection profiling. Based on a case study of the Larderello area we discuss the influence of seismic velocity uncertainties in geothermal prospecting and highlight the role of unrecognized seismic anisotropy. For the field study we investigated the anisotropy of typical rock samples under simulated in-situ HP/HT conditions. It turns out that the target horizons may be found up to 300 m shallower and 200 m horizontally displaced compared to the isotropic case due to anisotropic bias. Correspondingly, the uncertainty of temperature extrapolation may increase from 10 to 20%.