Geothermometry On Fluids Circulating In A Carbonate Reservoir In North-Central Italy
Journal Article: Geothermometry On Fluids Circulating In A Carbonate Reservoir In North-Central Italy
AbstractThe peri-Tyrrhenian belt of north-central Italy is a site of large-scale fluid circulation in Mesozoic carbonate-anhydritic formations of thermal waters with Ca-sulfate composition. These carbonate formations are the principal geothermal reservoir of the known Italian geothermal fields. Owing to differences in the regional structure, these carbonate rocks may have an intrinsic high or low hydraulic continuity. The Ca-sulfate springs that surface at the periphery of these formations have circulated in the unconfined parts of the carbonate aquifer. The high-salinity Na-chloride geothermal fluids discharge from the confined parts of the same reservoir rocks. These fluids are somewhat separated from fluids generated in the unconfined parts by possible barriers of low permeability. They are also diluted with the Ca-sulfate waters and have re-equilibrated at lower temperature. Because of these conditions, the assessment of the deep reservoir temperatures cannot be made using rapidly re-equilibrating geothermometers - such as the SiO2 geothermometer. The latter reveals the temperature of the unconfined aquifer at best. The study of the geohydrological nature of the reservoir rocks, the composition of liquid and gas phases and the statistical behavior of the main chemical geothermometers applied to the shallow cold waters of the principal Italian geothermal areas, has shown that the geothermometer based on ratio seems to be the most reliable to evaluate the deep temperatures inside the confined parts of the carbonate reservoir.
- A. A. Minissale and V. Duchi
- Published Journal
- Journal of Volcanology and Geothermal Research, 1988
- Not Provided
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A. A. Minissale,V. Duchi. 1988. Geothermometry On Fluids Circulating In A Carbonate Reservoir In North-Central Italy. Journal of Volcanology and Geothermal Research. (!) .