| Title | Numerical Modeling for the Larderello-Travale Geothermal System (Italy) |
|---|---|
| Authors | Antonio Barelli, Maurizio Cei, Ferdinando Lovari and Paolo Romagnoli |
| Year | 2010 |
| Conference | World Geothermal Congress |
| Keywords | Numerical modeling, TOUGH2, Larderello, Travale, Italy |
| Abstract | The Larderello-Travale field was simulated via the three-dimensional numerical model TOUGH2. This work was mainly aimed at investigating: o The superheated steam production mechanism; o The interactions between the geothermal field and the surrounding deep aquifers including their long distance pressure draw-down; o The field sustainability. The simulated area is 5000km2, abundantly covering the geothermal fields of Larderello and Travale, whose area totals “only” 300km2. This choice was made to evaluate the pressure draw-down induced in the faraway aquifers by production exploitation. To fulfill the work aims, no constant pressure boundaries (i.e. mass sources) were introduced. The depth of the domain was set to 7000 m according to a seismic reflection horizon which is believed to represent the reservoir bottom. This bottom is impermeable, but allows the natural heat flow to take place. The reservoir top is modeled as an impermeable layer of rock that acts as a cover. The only interactions with the environment are natural manifestations and some well known shallow aquifers where the cover is absent. The natural state was successfully simulated assuming a natural manifestation flow-rate of some 10% of the present extraction rate.The rock permeability was tuned to match the initial pressures and temperatures. The history of the industrial exploitation was then introduced and the resulting pressure distribution was compared with the actually recorded data achieving satisfactory results. The production mechanism resulted to be not only the steam expansion in the superheated reservoir core, but also and mainly the liquid evaporation in the steam-water contiguous zones. The field production results to be sustainable at least for the next 100 years. |