Table 1 Data related to temperature profiles obtained from unused wells
Symbol/Type/Year of drilling | Altitude amsl (m) | Depth max (m) | Thermal gradient (°C/1000 m) | Interval (m) | Maximum temperature (°C) |
|---|---|---|---|---|---|
KO1/P/1988 | 56 | 116 | 500/175 | 20–100/100–120 | 80 (PT) |
LTR1/SH/1994 | 58 | 113 | 140 | 20–100 | 34 (BH) |
LTR2/SH/1994 | 56 | 153 | 110 | 30–140 | 33 (BH) |
EB2/P/1994 | 119 | 210 | 184 | 20–190 | 52.5 (BH) |
EB3/P/1994 | 65 | 253 | 230/433/100/330/200 | 20–120/120–150/160–170/180–250 | 92.5 (BH) |
TRA/P/1984 | 15 | 52 | Artesian Flow | 51 | |
MET/P/2007 | 83 | 170 | 240 | 20–110 | 44 |
AA1/SH/1999 | 30 | 465 | 170/60/140 | 20–190/190–200/200–400 | 89.5 (BH) |
AA2/SH/1999 | 10 | 410 | 40 | 20–350 | 30.5 (BH) |
AA3/SH/2000 | 44.10 | 450 | |||
AA3/P/2000 | 43.46 | 360 | 200/100/460/Isothermal | 20–200/200–220/220–280/280–360 | 89.2 (PT) |
AA4/P/2000 | 24.3 | 430 | 96/138/110/Isothermal | 20–240/250–280/290–380/390–430 | 64 (BH) |
AA5/P/2000 | 7.23 | 420 | 40 | 20–420 | 32.8 (BH) |
AA6/P/2016 | 43.23 | 410 | 45/112/162/342/152/240 | 30–60/70–120/130–170/180–190/200–360/370–400 | 75–77 (BH) 99 (PT) |
ARA/P/2004 | 29.45 | 500 | 160/60/120 | 20–250/250–270/280–480 | 80.3 (BH) |
CHA/P | 45.35 | 200 | 238/115 | 20–160/170–180 | 57 (BH) |
DEM/P/2003 | 49.6 | 300 | 242/184 | 20–150/160–260 | 73.3 (BH) |
AR11/P | 40 | 140 | 90 | 20–140 | 26.5 (WH) |
LTR3/P | 28 | 150 | Isothermal/80 | 0–130/140–150 | 25.9 (BH) |
KO1 | Extremely high thermal gradient 45 °C/100 m in the first 100 m of highly altered and impermeable caprocks with clayey, tuffaceous materials, and altered dacite with sulfides mineralization. Fractured dacites between 110 and 120 m. Flow rate: 20 m3/h | ||||
LTR1 | Rectilinear temperature profile and high gradient. Slim decommissioned well in the red clayey part of the cap rock | ||||
LTR2 | Well, decommissioned in the red clayey part of the cap rock. High gradient in the first 100 m. Lateral thermal outflow | ||||
EB2 | Altered dacites. No significant water flow rate (< 10 m3/h). High mean gradient. Gradual deepening of isotherms northwards | ||||
EB3 | Gradient remarkably high for almost overall profile apart from a limited convex upward inflexion between 150 and 170 m. Highest static temperature 92.5 °C at 250 m depth. Lower aquifer in low permeability tuffites in the last 10–20 m. Flow rate 40 m3/h | ||||
TRA | Thermal spring discharge area. Well in high fragmented rhyolite with artesian flow. Pumping rate > 120 m3/h when tested | ||||
MET | Rectilinear conductive profile. High thermal gradient. Aquifer in low permeability volcanic rocks, at 160–170 m | ||||
AA1 | Nearly rectilinear temperature profile. Between 190 and 200 m. upper aquifer in volcaniclastics. High mean thermal gradient | ||||
AA2 | Overall profile rectilinear. Minimum background thermal gradient (42.5 °C/1000 m) for the entire exclusive area | ||||
AA3 | Casing until 354 m. Inadequate critical information for the vertical extension of the convective system in the ignimbrites | ||||
AA3 | Irregular temperature profile. Conductive 20–200 m and 220–280 m. Rectilinear temperature increment with sharp break in the lower segment presumably due to the extremely low thermal conductivity of the clayey formation. Upward convective cell 200–220 m (upper aquifer). Isothermal profile 280–360 m. Maximum temperature 89.4 °C. Flow rate > 100 m3/h | ||||
AA4 | Temperature profile nearly rectilinear with minor irregularities. Trend for isothermal evolution in the basal part | ||||
AA5 | Temperature profile identical with those of the well AA2 | ||||
AA6 | Drilled on the hanging wall of the active Fault 3. Hottest temperature measured in the AGF (99 °C) with a continuous upward trend after a 75 h pumping test, due to lateral advection triggered by the continuous water level drawdown. The BH temperature has undergone a gradual but strong cooling down process before equilibration at 78 °C after 24 months | ||||
ARA | Adjacent to the well AA1E. The deepest well in the field. Lower aquifer (ignimbrites) not reached. Max flow rate 25 m3/h at 65 °C from low permeability intermediate aquifers in volcano-sedimentary sequences. High mean thermal gradient | ||||
CHA | High thermal gradient for overall profile. Tapping in the Upper volcano-sedimentary aquifer with maximum flow rate 25 m3/h | ||||
DEM | Rectilinear thermal profile. Gradient remarkably high. Main productive formation not reached. Max flow rate 25 m3/h | ||||
AR11 | Irrigation well 1220 m westwards of the AA3 well, in a fractured zone, bounding the western edge of the geothermal area | ||||
LTR3 | Irrigation well with artesian flow, 2600 m north of the Traianoupolis thermal spring within low cohesion sediments |