An Update of the Larderello-Travale/Radicondoli Deep Geothermal System

Abstract

Within the framework of research in the marginal areas of the Larderello-Travale/Radicondoli geothermal system, several exploration wells have revealed that the deep reservoir extends even below zones of medium or low shallow thermal anomaly. North-east of the Larderello field, the shallow wells crossed a known low-temperature (100?C) CO2 saturated carbonate aquifer. At greater depth, in the phyllitic metamorphic basement, a steam reservoir has been discovered at depths of about 3000 m. The temperature and pressure are around 300?C and 7 MPa, respectively (Cappetti et al., 1985; Cappetti and Stefani, 1994; Cappetti et al., 1995).
Other exploratory wells, drilled in the area south of Travale/Radicondoli, discovered the same deep reservoir, although large outcrops of permeable and cold carbonate rocks are present.
On the basis of these positive results, specific development projects have been implemented in these two areas, leading to the installation of new power plants for an additional capacity of 80 MWe (Cappetti et al., 2000).
Larderello and Travale/Radicondoli deep reservoirs have the same temperature (300-350?C) and pressure (4-7 MPa): they belong to the same geothermal system. The surface extension of this deep field is about 400 km2. A new extensive deep drilling exploration program has been launched in 2004.