The Alfina 15 well - deep exploration in the geothermic field of Torre Alfina
The well drilling was performed by ENEL-National Geothermal Unit with a MASS 6000 E rig. The goal consisted of a presumed second deeper reservoir within a depth of 4000 m. Beneath the flyschoid cover, the well crossed repeated tectonic units of the Tuscan Series overlying, from 3545 m, analogous formations of the Umbrian Stratigraphic Succession. The drilling then continued to the final depth of 4826 m. For the first time the Mesozoic carbonate formations, which make up the first regional geothermal reservoir, were crossed for such a great thickness, approximately 3700 m, above a presumed deeper impermeable basement. The tectonic thickening of the permeable rocks constituted a single reservoir with extremely low thermal gradients (0.2-0.3 C/10 m) and temperatures ranging between 140 C and 210 C. Despite stimulation the well proved unproductive owing to low local permeability. From a drilling technology point of view the well did not present any difficulties, despite the great depth never before reached in geothermal wells in Italy.
Bibliographic Reference: EUR 12144 IT (1990) 295 pp., MF, ECU 12
Record Number: 199010173 / Last updated on: 1994-12-01
Original language: it
Available languages: it