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Abstract

The objective of the study was the stimulation of two dry wells in the geothermal field of Latera by means of hydraulic fracturing and acid treatment. Latera 6 well: total depth is 2017 m of which 1084 m is cased. The injection affects the total open hole section. The well head pressure remained between 6,8 and 6,3 MPa for an injection rate of 144 m**3/h and mounted to 7.4 MPa for a rate of 200 m**3/h. The absorbing formations are deducted from the temperature profile in the well after injection. Latera 1 well: total depth is 2573 m with 1160 m cased. The aim is to inject 300-500 m**3/h into the open hole section. The short duration injection (hours or days) in both wells resulted in the opening of a large existing fracture that didn't close after the pumping stopped. Pumping during weeks and months did not improve the situation. It was impossible to establish a connection through artificial fracturing with the network of natural fractures and the injectivity dropped to lower values as before when filtration through the fracture walls became the controlling step in the process. Both injection experiments created intense microseismic activity. The intensity of the individual events was very low. The strongest reached a level of 0.7. These seismic events are attributed to thermal fracturing of the rock when cold water reached rocks with a temperature of 220 degrees C.

Additional information

Authors: ENEL ENEL, UNITA NAZIONALE GEOTERMICA, PISA (ITALY), ENEL, UNITA NAZIONALE GEOTERMICA, PISA (ITALY)
Bibliographic Reference: EUR 9722 IT, MF (1985), 209 P., BFR 450, EUROFFICE, LUXEMBOURG, POB 1003
Availability: Can be ordered online
Record Number: 1989123117500 / Last updated on: 1987-01-01
Category: PUBLICATION
Available languages: it