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Contenuto archiviato il 2022-12-27

DRILLING FOR EXPLOITING THE GEOTHERMAL RESERVOIR AT NISSYROS FOR ELECTRICITY GENERATION

Obiettivo

To complete the second stage in development of a geothermal reservoir located on the island of Nissyros. Testing of well 1 showed the following characteristics: maximum temperature 450 C; flow-rate - 10 t/h; fluid enthalpy - 550 Kcal. Well N.2. will cross the reservoir at between 1,300 and 2,000 : it will be completed with a 7" slotted liner. Expected production is 12 t/h (10 t steam + 2 t water).
A first stage power generation plant of 3 MW is planned using well N.2. as a production well and N.1. as the injection well : in a second stage two other production wells are planned. Ultimately it is expected that a capacity of 40 MW will be installed on the island.
As a first step, the installation of the 3 MW plant will yield an estimated saving of 2,500 TOE/y. A payback of 40 years is indicated on a total project cost of DRA 860 millions.
Productivity of well N.1. exceeded forecasts with an estimated steam flow-rate of 2.25 MW (allowing for the fact that some of the power produced was to be used for gas extraction).
The two wells are 800 m apart with a major fault running NE-SW between them, through which, in keeping with the other major faults, high enthalpy, high temperature, high salinity fluids will be brought from deep geothermal systems to higher levels.
One problem which will require further study is the silica and CO2 content, as this may result in scaling problems.
Between June and November 1983 the N.2. well was drilled to a final depth of 1,545 m and the reservoir was found to extend from 1,081 to 1,547 m in lavas and tuffs at the top, and thermometamorphic rocks from 1,100 m at the bottom.
Petrographic indicators and geochemical geothermometers indicate a reservoir temperature of 250 C. A casing of 9 5/8" has been cemented to 1,044 m with a 7" slotted liner at 1,019 m.
On completion, well tests showed the following results: flow-rate 63.3 t/h (steam 29.3; vapour 30.4; CO2 1.1; water 32.9); enthalpy 360 Kcal; wellhead pressure 14.7 Kg/m2; wellhead temperature 200 C.
Brine chemical composition is similar to that of the fluids produced by well N.1. Total salinity is 56.5 G/l (liquid phase); average H2S is 0.4 g/l with an average concentration of CO2 at 24.2 G/l.

Invito a presentare proposte

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Meccanismo di finanziamento

DEM - Demonstration contracts

Coordinatore

PUBLIC POWER CORPORATION (PPC)
Contributo UE
Nessun dato
Indirizzo
HEP DEV. DEPT 56-58 AGISIALOU STR.
10436 Athens
Grecia

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Costo totale
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