Deep Drilling Results and Updating of Geothermal Knowledge of the Monte Amiata Area

Abstract

Deep geothermal exploration begun in Bagnore and Piancastagnaio geothermal fields in the late has led to the discovery of a deep water-dominated reservoir with a temperature of and a pressure of 20-25 In the Piancastagnaio field 24 wells have been drilled, with a success ratio of about 90% and an average specific productivity of about 4 MW per well. Three 20 MW power plants are in operation, one is presently under construction and will be on line in 1995, and another three are be installed. In the Bagnore field seven wells have been drilled to assess the resource. In this area too the results were positive: it is planned to drill 13 wells and build three 20 MW power plants. The geological and geophysical data have been reconsidered and the structural features of the geothermal reservoir have been reconstructed. A recent granitic intrusion (the probable source of the Monte Amiata thermal anomaly) has been hypothesized at a depth of 7 km over a much wider area than previously believed. An additional seven deep exploratory wells have therefore been planned at the borders of the geothermal and in other areas of Monte Amiata.