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Contenu archivé le 2022-12-27

TOWN DISTRICT HEATING USING GEOTHERMAL ENERGY [STAGE 1]

Objectif

To supply 80% of the needs of a district heating scheme (30,000 apartments) in Ferrara by means of geothermal energy. The reservoir formed by the Dolomite in Upper Jurassic and Triassic strata lies between 1,200 and 2,000 m depending on the geological structures. The total reservoir thickness exceeds 700 m. Anticipated flow-rate is 300 m3/h per well with a 100 deg. C temperature and a total salinity of 65 g/l.
The annual savings of 7,500 TOE will contribute to a payback of 24 years.
Since production has been higher than forecast, fewer wells than originally planned will be drilled, through they will be spaced further apart (to allow for the permeability due to fractures). Bearing in mind the characteristics of the reservoir, the constant temperatures and the very high potential of the upper reservoir, it is reasonable to contemplate sinking production wells down to the upper reservoir at about 1,300 m. The fluid that has cooled off in the lower reservoir (whose productivity index is higher) will be reinjected. This system should boost the yield from the pairs of wells and from the fractures. Agreement has been reached to heat 5300 flats from the two first wells (C2 and C1) only 1,080 m apart and operating as a pair (with C2 as production well). The second production well (C3) will not be drilled until the performance of the first pair has been analysed and the operating conditions optimised to allow further exploitation of these exceptionally promising resources.
A production well (C2) was drilled in June and July 1981 to a depth of 1,960 m and 1,080 m apart from oil exploration well (C1).
Reservoir formation is of Mesozoic brecciated medium-grain dolomite. Upper reservoir (25%): between 1,170 m and 1,390 m. Lower reservoir (67%): between 1,790 and 1,960 m. The temperature of 100 deg C is virtually constant from 1,250 to 1,960 m; salinity is 65 g/l. The reservoir has been left as 8" 1/2 open hole below 890 m. Static level: -51 m; - net pay - 736 m; average permeability - 130 mD; transmissivity - 95 D.m; skin: + 3,2; PI (stabilised) - 105 m3/h/kg/cm2. Trials, both air-lift-assisted and assisted by submerged pumps, carried out without acidification at 50 m3/h and 125 m3/h with a very low drawdown. The production figures suggest that, unlike well C1, this reservoir has not been completely traversed. Nevertheless C2 still has far greater capacity than C1. The fluid collected at the surface was found to contain H2S (0,2 g/l) CO2 (0,47 g/l) andtraces of hydrocqrbons (N2 + CH4).

Thème(s)

Appel à propositions

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Régime de financement

DEM - Demonstration contracts

Coordinateur

ENI SpA- AGIP
Contribution de l’UE
Aucune donnée
Adresse
VIA EMILIA 1
20097 S. Donato Milanese (MILANO)
Italie

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Coût total
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