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MULTIDISCIPLINARY APPROACH OF THE DATA INTERPRETATION OF A GEOTHERMAL FIELD. APPLICATION TO THE BEHAVIOUR FORECASTS OF THE MOFETE FIELD.

Objective

TO ELABORATE AN INTEGRATED MODEL OF THE MOFETE GEOTHERMAL FIELD, IN ORDER TO IMPROVE MANAGEMENT OF THE RESERVOIR.
An evaluation of the geothermal potential of the Phlegrean Fields is presented using a 3-dimensional model called CHARGR.
For this reason the mining and petrophysical data from the drilling and tests done in the wells of the Permit Lagi di Patria were used. The simulation of the dynamic behaviour of the field confirmed the result of previous simulations, which indicated the installation of electrical power, at 7.5 MW and 15 MW respectively, using the existing wells and with maximum development of the field.

The values refer to a 25 year economic life of the field and in the present work, this hypothesis is always maintained.

The resulting powers were, in the 2 situations, 9.5 MW and 20 MW respectively, with a slight decrease of power with time. The improvement obtained using this model was probably due to the possibility of taking into account the presence of carbon dioxide; this gas has a noticeable effect on the fluid upflow in the well, by reducing the hydrostatic head in the borehole and thus permitting the extraction of geothermal fluid with lower pressure at the depth of the productive layers. Moreover the simulation ascertained the absolute necessity of fluid reinjection, in order to supplement the insufficient natural recharge.

In the 9.5 MW scheme using the existing wells, the flow rate remained constant while the power generated decreased from 9.61 to 9.34 MW at the end of the 25 year life of the field.

For the maximum developemnt of the field, it will be necessary to drill 7 new successful wells, 4 as productors and 3 as reinjectors.

The total flow rate varied from 203.0 Kg/s to 185.6 Kg/s while the power decreased from the initial 22.76 MW to 19.66 MW at the end of 25 years.

During this study all exploration, drilling and production test data were considered. In particular the long term results were very important because interference data gave reliable information on the average characteristics of the geothermal reservoir. Nevertheles s the documentation showed the necessity of carrying out new tests for a better knowledge of the characteristics of some wells, especially Mofete-2.
DATA COLLECTION HAS BEEN COMPLETED ALREADY, AND THIS CONTRACT COVERS ELABORATION OF THE FIELD MODEL (BUILDING ON A PREVIOUSLY DEVELOPED SIMULATION), CALIBRATION OF THE MODEL AGAINST THE KNOWN BEHAVIOUR OF THE MOFETE FIELD AND THEN USE OF THE MODEL TO PREDICT FUTURE FIELD BEHAVIOUR UNDER DIFFERENT PRODUCTION=REINJECTION CONDITIONS. THIS WILL ASSIST IN THE BETTER MANAGEMENT OF THE MOFETE FIELD, WHILE THE TECHNIQUES DEVELOPED SHOULD BE APPLICABLE SUBSEQUENTLY TO OTHER HIGH-ENTHALPY FIELDS.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Agip SpA
Address
Via Emilia 1
20097 San Donato Milanese
Italy