SUPPLY OF GEOTHERMAL ENERGY TO DISTRICT HEATING NETWORK [STAGE 2]

Ziel

To utilize a geothermal reservoir by means of one pair of wells. The production well was drilled in 1982-83 and produces 100 m3/h at 45 deg C and 160 g/l salinity from a detrital formation (Triassic Gassum) at 1,200 to 1,400 m. The injection well is to be drilled at 1.5 km from the production well, to a final depth of 1,280 m. The plant will operate on fuel oil and be connected to the existing district heating system. The productivity of the Triassic formation (Gassum) will provide 20% of the heating requirements, representing an average annual energy saving of 3,400 TOE.
Assuming a constant energy price, payback is estimated at 24 years and the total project cost DKR 87,8 million.
The planned demonstration plant with 120-140 m3/h geothermal water flow has a computed payback time of approx. 20 years.
The project is successful and a 1.26 Mw pilot plant is now in operation, representing the first geothermal operation in Denmark.
The water is reinjected at a flow rate of 34 m3/h after heat extraction by heat pump and the heat produced is then diverted to the existing Thisted district heating network. A 6 Mw geotherml plant is now foreseen (see Contract GE/00301/85/DK). Both wells have been completed with the same screen and gravel pack. Injection tests were carried out between March and Summer of 1985. The connecting pipe between the two wells became blocked and pressurised by nitrogen and the plant restarted during September. Injection since then has been carried out without any problems. The long term corrosion tests which were carried out between February 1984 and May 1985 showed a measured corrosion 9 times lower than forecast at 0.1 mm/y, a result which verifies the possibility of running a brine system free of oxygen contamination under industrial conditions. No patents orlicences are expected.
Drilling of the injection well to 1,207 m was completed in December 1984. A 9 5/8" casing is cemented to 1,207 m and the reservoir drilled in 8 1/2" with 16" underreaming. It was completed with a 6" screen, gravel-packed from 1,169 m to the bottom. The gravel pack was cleaned with nitrogen gas lift prior to and after HCL stimulation.
Completion of Thisted Well III was followed by Thisted Well II in January 1985 by milling a 36 m section window in 9 5/8" casing, 16" underreaming and setting of 6" screen gravel-packed as in Thisted Well III.
During January 1985 a submersible pump was set into Thisted Well II (the production well) and after initial set-backs is now running without any problems with no decrease in capacity observed during the operation.
See project GE./00078/81/DK and project GE./00301/85/DK.

Programm/Programme

ENG-ENALT 2C - Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985

Thema/Themen

4.1 - HEATING

Aufforderung zur Vorschlagseinreichung

Data not available

Finanzierungsplan

DEM - Demonstration contracts

Koordinator

DANSK OLIE OG NATURGAS A/S

EU-Beitrag

Keine Daten

Adresse

AGERN ALLE 24-26
2970 Hoersholm
Dänemark

Gesamtkosten