Modeling Highly Buoyant Flows in the Castel Giorgio: Torre...

Research ArticleModeling Highly Buoyant Flows in the Castel GiorgioTorre Alfina Deep Geothermal Reservoir

Giorgio Volpi 1 Fabien Magri23 Francesca Colucci4 Thomas Fisher2

Mattia De Caro1 and Giovanni B Crosta1

1Department of Earth and Environmental Sciences University of Milano-Bicocca Piazza della Scienza 4 20126 Milano Italy2Department of Environmental Informatics (ENVINF) Helmholtz Centre for Environmental Research (UFZ)Permoserstraszlige 15 04318 Leipzig Germany3Freie Universitat Berlin Hydrogeology Malteserstr 74-100 12249 Berlin Germany4Ricerca di Sistema Energetico (RSE) SpA Via Rubattino 54 20134 Milano Italy

Correspondence should be addressed to Giorgio Volpi gvolpi4campusunimibit

Received 22 August 2017 Accepted 7 November 2017 Published 1 February 2018

Academic Editor Francesco Italiano

Copyright copy 2018 Giorgio Volpi et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The Castel Giorgio-Torre Alfina (CG-TA central Italy) is a geothermal reservoir whose fluids are hosted in a carbonate formationat temperatures ranging between 120∘C and 210∘C Data from deep wells suggest the existence of convective flowWe present the 3Dnumerical model of the CG-TA to simulate the undisturbed natural geothermal field and investigate the impacts of the exploitationprocess The open source finite-element code OpenGeoSys is applied to solve the coupled systems of partial differential equationsThe commercial software FEFLOW is also used as additional numerical constraint Calculated pressure and temperature havebeen calibrated against data from geothermal wells The flow field displays multicellular convective patterns that cover the entiregeothermal reservoir The resulting thermal plumes protrude vertically over 3 km at Darcy velocity of about 7 lowast 10minus8ms Theanalysis of the exploitation process demonstrated the sustainability of a geothermal doublet for the development of a 5MW pilotplant The buoyant circulation within the geothermal system allows the reservoir to sustain a 50-year production at a flow rateof 1050 th The distance of 2 km between the production and reinjection wells is sufficient to prevent any thermal breakthroughwithin the estimated operational lifetime OGS and FELFOWresults are qualitatively very similar with differences in peak velocitiesand temperatures The case study provides valuable guidelines for future exploitation of the CG-TA deep geothermal reservoir

1 Introduction

Since the 1970s the increasing threat of a worldwide energycrisis has prompted many governments to reduce their de-pendence on traditional nonrenewable energy sources focus-ing on renewable ones (eg geothermal energy hydroelec-tric wind-energy and several forms of solar energy suchas bioenergy biofuel photovoltaic and solar-thermal energy[1]) Geothermal energy is expected to play an increasing roleto meet future power demand This is related to its enor-mous exploiting potential which is capturing the attention ofindustries also due to technological advances in the explo-ration of promising geothermal fields [2 3]

Most of the world famous geothermal energy sourcesexploited today are associated with volcanic andor recent

tectonically active areas Important examples are the geother-mal areas of Yellowstone [4ndash6] northern California [7] thePannonic Basin [8] and theRhineGraben [9ndash11] Italy strong-ly contributes to the development of geothermal power gen-eration In 1904 the world first electrical power was producedfrom a geothermal energy source in the Larderello site (Tus-cany central Italy) [1 12ndash18]

Beyond the world famous Larderello system fossil andactive hydrothermal manifestations are distributed all alongthe Preappennine belt of central Italy facing the Tyrrheniancoast This area has undergone both lithospheric extensionand upper mantle doming Such processes have been activesince the Miocene [19 20] and are likely sustained by massand heat fluxes from the upper mantle This is suggestedby the intense tectonic and volcanic activity associated with

HindawiGeofluidsVolume 2018 Article ID 3818629 19 pageshttpsdoiorg10115520183818629

2 Geofluids

extremely high and variable surface heat-flux anomalies [2122] All these processes document a predominant heat trans-fermechanism by verticalmass flow which accumulates largeamount of geothermal resources at accessible depths in theupper crust Two geothermal fields in the area characterizedby heat flow values of up to 1000mWm2 (Larderello system)and 600mWm2 (Mt Amiata system) [11] are currentlyexploited for the production of electricity

Recently various projects were set up on a regional basisto investigate the geothermal potential of the Italian Tyrrhe-nian facing areas Moreover research and development ofnew exploitable geothermal fields have been encouraged bythe approval of specific decrees of law (ie Legislative Decreeof 11 February 2010 n 22 modified by Legislative Decree of3 March 2011 n 28 and Article 28 of Decree of Law of 18October 2012 n 179)

Among the identified promising areas the Castel Gior-gio-Torre Alfina field (CG-TA northern Latium Figure 1)is an example of an early explored and so far not exploitedmedium-enthalpy geothermal system [23ndash25] Detailed hy-drogeothermal data available for the selected area since early70s show that the CG-TA is a potential geothermal reservoirwith medium thermal characteristics (120∘Cndash210∘C) whosefluids (pressurized water and gas mainly CO

2) are hosted

in a fractured carbonate formation [24 26ndash30] Data fromthe deepest geothermal drilling in the area (Alfina015 wellmax depth minus4826m asl see Figure 1 for location) showa highly variable temperature gradient ranging between015∘C10m and 21∘C10m [31] Such a strong variation likelyindicates the presence of highly convective flow within thereservoir rocks This finding makes the CG-TA area suitablefor future exploitation through a new generation 5MWegeothermal pilot power plant Following the guidelines of theabove-mentioned Italian legislative decrees this exploitationproject is characterized by no gas emission to the atmosphereand total reinjection of the geothermal fluid in the sameproducing geological formation (ie geothermal well doubletsystem)

Planning of such challenging geothermal field exploita-tion projects requires an appropriate numerical modeling ofthe involved heat and fluid transfer processes In the last20ndash25 years models have been set up for more than 150geothermal fields worldwide [18 22 32ndash43]These numericalmodels allow us to define wellrsquos system design fracture pathsextraction rates and temperature of injected and producedthermal waters to interpret hydraulic tests or stimulationprocesses and to predict reservoir behavior during geother-mal power production Therefore they are mandatory tooptimize the productive capacity and the thermal break-through occurrence [1 44]

Mathematical modeling of a geothermal reservoir allowsreconstructing both the deep natural fluid circulation andphysicalchemical fluid characteristicsThis can be of interestat geothermal sites where high temperatures and strong cor-rosion caused by very acidic involved fluids occur In somecases the fluids may react chemically with the hosting rocksprecipitating minerals that diminish reservoir permeabilityby pores and fractures obstruction [45] These phenomena

create spatially variable patterns of mineralization and per-meability thus affecting the exploitation of the reservoir [4546]

Numerical modeling of exploited geothermal systemsshould include (i) a solid conceptual model of the reservoirgeology and structure (ii) the location and geometry of wellsand possible fractures systems and (iii) the parameterizationof hydraulic thermal mechanical and chemical (HTMC)properties of the reservoir and of the involved fluids [47]

The aim of the present study is to build the 3D numericalmodel of the deep medium-enthalpy CG-TA reservoir to re-produce the highly convective undisturbed present-day nat-ural state of the reservoir These results validated against thepressures and temperatures measured in geothermal wellsare afterward used to investigate the feasibility of a geother-mal power production configuration (ie injection and pro-duction wells) The analysis is performed on a hypothetical50-year operational life cycle adopting a well doublet systemat a 1050 th flow rate [48] The finite-element open sourcecode OpenGeoSys [49] is used to build the hydrothermal(HT) model As additional numerical constraint the resultsare compared against those obtained with the commercialfinite-element code FEFLOW [50]

First the hydrogeothermal data derived from geophysicalinvestigations and from geothermal wells are described andused to build a conceptual and numerical model of the CG-TAreservoirThen thenumerical approach based on theOpen-GeoSys software is given Results are obtained both at short-term (ie operational) and long-term (ie full reservoirrecovery) time scale Besides providing valuable guidelinesfor future exploitation of the CG-TA deep geothermalreservoir this study highlights the importance of field dataconstraints for the interpretation of numerical results of fluidprocesses in reservoir-scale systems

2 Reservoir Characterization

21 Regional Geological Setting The occurrence of medium-and high-enthalpy geothermal fields in central Italy islocalized along the Tyrrhenian margin of the Apennines(Figure 1) The complex geologic and tectonic settings ofthis area have been studied by several authors ([51ndash54] andreferences therein)

The present-day structural setting of the Tyrrhenian coastfacing regions represents a heritage of compressive and exten-sional geodynamic processes that began in the Oligocene(ie 30MaBP) with the Alpine-Apennine orogenesis [18 55]The compressive phase resulted in the formation of fold-and-thrust-belts and associated piggy-back basins with NNE-SSW oriented trend [56ndash58] Then the subsequent exten-sional phase due to the Tyrrhenian back-arc extensionresulted in the formation of NWndashSE tectonic basins and inthe crustal thinning with consequent upwelling of magmabodies and increased heat flow [18 21 22 59 60]

Due to the interplay of all these phenomena the geologicand structural settings of the area are quite complex andinvolve many different lithostratigraphic unitsThemain andmost widespread complexes from the shallower to the deeperones [18 25 61 62] (Figure 2) are namely

Geofluids 3

Si

Lo

Pd

Tu

Sa

ER

Ap

La

Ve

Ca

Cp

Ab

Bs

TST

Ma

Li

Um

FVG

Mo

AV

CG2

CG1A CG1CG3A

CG3

CG14CG14A

CG14BCG14CBolsena lake

CG-TA field

Mt Cetona

A14A04

A02A15

A01A13A05

R01A07

G01bisG01

GC1B01

Ba19

(b)

Administrative regional boundaryModel domain (CG-TA field)Cross section

Geothermal reservoirGeothermal wellsProduction wells

Injection wells

B

San Cascianode Bagni

(a)

5(km)

075(km)

Vulsini caldera

0 15

Tuscany

Latium

Um

bria

N

N

0 10

Tyr rhenian margin of Apennines

Figure 1 (a) Geographical setting of the CG-TA geothermal field (red dashed line) The geothermal producing reservoir (red shaded area)the cross-section traces A-B and the existing geothermal wells drilled in the area are shown (where in the labels A stands for Alfina G forGradoli GC for Grotte di Castro B for Bolsena and Ba for Bagnoregio) (b) Enlargement of the SE area of the reservoir with location of the5 production wells (CG1 CG1A CG2 CG3 and CG3A) and the 4 injection wells (CG14 CG14A CG14B and CG14C) used in the simulationof the 5MW field exploitation

(i) volcanic complex volcanic products including tufflavas and pyroclastic rocks characterized by variablethickness with a maximum of 200 meters

(ii) neoautochthonous complex clays with limited sandcontent conglomerates and detrital limestones in adiscontinuous layer 50 to 160 meters thick

(iii) Liguriansub-Ligurian complex Jurassic-Eocene clay-ey-marly units in flysch facies sandstones marlylimestones and ophiolites They are characterized bya highly variable thickness ranging from 500 to 1800meters (RAI01 well see Figure 1) [61]

(iv) Tuscan and Umbria Nappe complex Triassic-LowerMiocene arenaceous and clayey-marly formationscalcareous-siliceous rocks dolostone and anhydritesThe upper portion of this formation is characterizedmainly by marly limestone and shales and is referredto as the ldquoScaglia formationrdquoTheTuscan and UmbriaNappe carbonatic formation reaches a thickness ofabout 3700 meters (Alfina015 well see Figure 1) [31]

22 The Castel Giorgio-Torre Alfina Geothermal Field TheCG-TA geothermal field (Figure 1) is located to the northof the Vulsini caldera [24] at the boundary between theTuscany Umbria and Latium regions (central Italy) TheTorre Alfina reservoir was extensively explored between the1970s and the 1990s We refer to the works of Cataldi andRendina [23] and of Buonasorte et al [24 31] for the detaileddescription of the geothermal explorations carried out inthe area These investigations culminated with the drilling

of eight geothermal wells with depths ranging from 563 to2710m and more recently with the drilling of a very deepgeothermal well (Alfina015 Figure 2) reaching the depth of4826m

The integration between stratigraphic borehole logs andgeophysical [24 31] and seismic [27] data identified the CG-TA geothermal reservoir as hosted in a structural high (iehorst structure highlighted in the correlation section ofFigure 2) of fractured Mesozoic limestones belonging to theTuscan and Umbria Nappe complex and marked by positivegeothermal and magnetic anomalies [63] Structural investi-gations performed in the area by Buonasorte et al [56] andPiscopo et al [64] provide a detailed description of the N-Sstriking postorogenic extensional faults bounding this horststructure and an analysis of the geometry orientation andkinematics of all the other tectonic features occurring in theTorre Alfina geothermal system

The first geothermal drilling campaign performed in theCG-TA field (1971-1972) was aimed to reach and cross theargillaceous and shaly terrains of the Ligurian and Sub-Ligurian complex These investigations allowed not only adetailed stratigraphic reconstruction but also the definitionof the basic characteristics of the geothermal reservoir fluids(eg pressurized hot water with average temperature of140∘C) and the detection of a gas capmade by 2 of dissolvedCO2 This 100-meter thick cap recognized only in the central

part of the field was extensively exploited until few years agofor CO

2storage by the well Alfina013 (Figure 1)

The target of the more recent campaign (1987-1988) wasthe deeper and hotter geothermal reservoir hosted in the

4 Geofluids

ESE NNWWNWA5 A13A7 A1 A2 A4 A14

400

1000

2000

m plusmn 0

SSE

400

0

1000

2000

1

2

3

4

5

6

Volcanic complex

Neoautochthonous complex

Ligurian complex

Scaglia complex

Tuscan nappe complex

Umbria nappe complex

minus5000

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

(m)

4362 m 1425 m 1853mRAI01 Alfina015 Alfina004 Alfina014

0 1 2(km)

Figure 2 Stratigraphic columns and correlation section (see trace in Figure 1) compared with the WNW SSE cross section by Buonasorte etal [24] RAI01 Alfina004 and Alfina014 wells belong to the first drilling campaign (1971-1972) while the deepest Alfina015 well was drilledon 1987-1988 The Castel Giorgio-Torre Alfina geothermal reservoir is hosted in a structural high (ie horst structure) of fractured Mesozoiclimestones belonging to Tuscan and Umbria Nappe complex (light and dark blue units)

metamorphic rocks lying underneath the calcareous forma-tionsThough the exploration did not reach themetamorphicbasement it demonstrated the presence of a single very thickcarbonatic reservoir (gt3700m thick) within which a highlyvariable temperature gradient of 015∘C10mndash045∘C10mwas recorded [31] These exploration wells resulted in mul-tiple pressure and temperature vertical profiles within the

geothermal field three of which are illustrated in Figure 3The available data stands in different depth ranges Alfina002well the shallower one with measured temperature datareaching minus500m asl the second well (RAI01) reachedminus2000m asl while the last and most recently drilledAlfina015 well provided a full temperature profile up to adepth of minus4000m asl The shallower Alfina002 and RAI01

Geofluids 5

Alfina002Alfina015RAI01

minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)

50 100 150 200 2500Temperature (∘C)

Figure 3 Temperature vertical profiles along 3 exploration wellsaccording to Cataldi and Rendina [23] Buonasorte et al [24 31]Locations of the selectedwells are reported in Figure 1The inversionof the Alfina015 well temperature profile and the values detected atthe top and at the bottom of the reservoir (140∘C at minus1050 metersbgl minus207∘C at minus4000 meters bgl) prove the highly convectivebehavior of the system

wells reaching only the top of the reservoir units registereda linearly increasing temperature with a high geothermalgradient in the range of 17ndash21∘C10m [24] This suggests amainly conductive heat transfer mechanism associated withthe cap rock impermeable units A similar trendwas observedin the shallower portion (up to ca 1000m depth) of thedeep Alfina015 well (Figure 3) At about 1000m a knick-pointand a thermal inversion are observed along the profileThe geothermal gradient below this depth ranges between015∘C10m and 045∘C10m Such a strong variation cou-pled with measured top and bottom nearly constant temper-atures of the reservoir fluids (ie 140∘C and 207∘C at 1050mand 4000 m depth resp [31]) point toward an intenselarge-scale convective flow confined in the area of the buriedstructural high

In summary the CG-TA area is an example of a promis-ing early explored and yet to be developed geothermal filedDespite the extremely favorable conditions for exploitation[23] its industrial development was not promoted till 2011 Anew geothermal research permit was requested for the TorreAlfina area aimed to the development of 2 new generation5MWe pilot doublet plants with reduced gas emission [3048]

23 Conceptual Model The spatial extent of the model isfundamental for a reliable simulation of the complex pro-cesses involved in a geothermal reservoir An overly restrictedscenario hampers a complete representation of the circulationinto the field whereas a very large one results in amore uncer-tain geological reconstruction and excessive computational

loading The model area covering about 293 km2 (Figure 4)is located north of the Vulsini calderas and it is bordered bythe Meso-Cenozoic ridge of the Mount Cetona to the northand by the Bolsena caldera structure to the south (Figure 1)The extent is large enough for the imposed boundary condi-tions not to interfere with the phenomena occurring insidethe geothermal field This is guaranteed by a horizontal dis-tance between lateral model boundaries and the geothermalfield of 75 km in the E-W direction and of 25 km in the N-Sdirection (Figure 4) Due to the large extent of the geothermalreservoir and its intrinsic geological complexity a completereview of the existing data and literature was required [23 2530 31 57 61 63 65]

The geological model was based on deep geological crosssections [24 61 65] and contour line maps of the contactsurfaces between geological formations [24 25] Major atten-tion was devoted in representing changes inside and outsidethe geothermal reservoir The base of the model was locatedat minus4500m asl within fractured limestone reservoir unitsThe upper limit was defined by a rather flat topographyderived from a 20 times 20-meter DEM derived topographyThisresulted in amaximummodel thickness of about 5 kilometers(from +600m asl to minus4500m asl see Figure 4)

The reservoir units are composed from bottom to topof evaporites limestones marls and radiolarites (Tuscan andUmbria series sl [65]) Such reservoir units are buried by thesealing units and crop out at San Casciano dei Bagni villageThe sealing units consist of an allochthonous flysch-type se-quence composed of arenaceous turbidites intercalated withlayers of shales marls and limestones overlaid by an ophi-olitic sequence (siliceous shales and sandstones includingblocks of gabbro and serpentinite) (Ligurian units sl [66])

As previouslymentioned the area has undergone a strongpostorogenic deformation phase resulting in strike-slip andsubordinate normal fault systems (with associated fracturenetwork) cutting and dislocating the internal architecture ofthe reservoir [60] No anomalous soil CO

2flux was recorded

by the detailed investigations performed by Carapezza et al[30]This indicates the effectiveness of the impervious behav-ior of both the sealing units which are continuous all over thereservoir area with a thickness of no less than 400meters andthe fault system connecting the geothermal reservoir with thesurface

In summary the conceptual model consists of sevenhydrogeological units (Figure 4) of which the upper threeform the sealing cap and the remaining comprise the reser-voir The volcanic complex (1) is the youngest one and it out-crops only in the southern part of themodel domainThis for-mation tends to thin towards the north where it is in contactwith the other sealing units represented by the neoau-tochthonous complex (2) and the Liguriansub-Ligurian com-plex (3) The shallower geothermal reservoir unit is referredas the Scaglia formation (4) a tiny layer mainly consisting ofargillites Below this the fractured limestone rocks of theTus-can limestone formation (5) and the deeperUmbria limestoneformation (6) are emplacedThe Scaglia Tuscan andUmbriacomplex units (numbers 4 5 and 6) were additionally sub-divided between formations stacked into the proper geother-mal reservoir (ie the real portion affected by convection

6 Geofluids


Ligurian complex Scaglia complex out

Volcanic complex

Tuscan nappe complex out Tuscan nappe complex in

Umbria nappe complex out Umbria nappe complex in

Scaglia complex in

Reservoir area

RAI01Alfina002 Alfina014

225 km

75km

25 km

5 km

13 kmXY

Z

Fault

Figure 4Three-dimensional geological conceptual model cut along the sameWNW SSE cross section realized by Buonasorte et al [24] (seeFigure 2) The same cross section as in Figure 1 is used to slide the model Model (ca 293 km2) internal subdivision shows the seven adoptedhydrogeological units named as reported in Table 1 Reservoir units (Scaglia complex Tuscan nappe complex and Umbria nappe complex)have been distinguished between formations stacked into the geothermal reservoir (unit name in) and those falling outside the producingarea (unit name out) Distances between reservoir area and lateral model boundaries are shown (75 km along E-W direction and 25 kmalong N-S direction)

phenomena with an extent of ca 73 km2) and those fallingoutside the producing areaThemodel includes also aNE-SWtrending subvertical fault (7) with a surface trace of aboutone kilometer a vertical extent of 15 km and imperviousbehavior

3 Numerical Modeling

31 Modeling Approach Based on the conceptual model arefined reservoir-scale three-dimensional thermohydraulic(TH) model was built to investigate the different processesinvolved in the CG-TA geothermal reservoir

The open source finite-element simulator OpenGeoSys(OGS) [49] was used to solve the differential equations gov-erning density-driven flows The mathematical and numer-ical formulation of the problem and the strongly coupledsystem of equations can be found in Kolditz et al [49]OGS fully implements several equations of state (EOS) inorder to reproduce temperature and pressure dependent fluiddensity and viscosity Here we used the polynomial fittingsintroduced by Magri et al [67] that are valid for a wide rangeof temperatures (0 le 119879 le 350∘C) and pressures (119901sat le 119901 le100MPa)

The model surface was discretized into 17768 triangularfinite elements satisfying Delaunayrsquos criterion by using theGMS software [68] Mesh refinement was applied to ensuresimulation robustness elements size decreases graduallyfrom 500 meters at model lateral boundaries to 10 metersclose to the fault zone and around the geothermal wells(Figure 5) We verified that a finer mesh did not affect thecalculated patterns

The 2D surface grid was extruded vertically using a fullyunstructured tetrahedral 3D mesh The total volume of themodel was discretized with 35 layers ranging in thicknessfrom 250 meters at the model bottom to a minimum of 10meters near the topographic surface In total the 3D meshconsists of 1720774 tetrahedral elements (Figure 5) that pre-serves all outcropping and internal pinching of the geologicformations

The two modeling challenges are (i) recreating thepresent-day highly convective unexploited natural stateof the CG-TA geothermal system and (ii) performing thepredictive analysis of the industrial exploitation process ofthe field Two scenarios are therefore presented [25] (1) Thefirst one referred henceforth to as ldquonatural state simulationrdquoreproduces the thermohydraulic dynamic conditions of thegeothermal reservoir without extraction or injection of fluidPressure and temperature values measured in the threegeothermal wells drilled in the area (Figure 3) were usedto constrain the numerical results (2) Once a qualitativelysatisfactory match between calculated and observed patternsin these three geothermal wells was obtained the calculatedtemperature and pressure fieldswere used to initialize the sec-ond simulation step The latter includes the operating condi-tions based on a reasonable configuration of injection andproduction wells This scenario referred to as ldquoexploitationprocess simulationrdquo also assesses the impacts of the exploita-tion process on the long-term (ie up to 10000 years) naturalgeothermal flow of the reservoir after the production stage

The same modeling framework (ie boundary condi-tions initial conditions equations of state and spatial andtemporal discretization) is applied to the finite-element com-mercial software FEFLOW

Geofluids 7

Topographic surface

Reservoir area

Model bottomDirichlet type BC

Production wells siteInjection wells site

P and T earth gradient

03∘C10m

- 1 bar10m

minus4500 minus4000 minus3000 minus2000 minus1000 0 670

Elevation (m)ca 160∘C ca 491 bar

Dirichlet type BC 15∘C 1 bar

Neumann type BC 0256 Wm2

Figure 5 Three-dimensional thermohydraulic model consisting of 35 slices with 17768 triangles for each slice and 1720774 tetrahedralelements The 35 slices are visible along the left model boundary Model elevation ranges from 670 to minus4500m asl (see color bar) whilethe 2D mesh is exploded below the model Three-dimensional structure of the reservoir producing units (ie Scaglia complex Tuscan nappecomplex and Umbria nappe complex) confined in the area of the buried structural high is shown in the central portion of the modeleddomain (color scale according to Figure 4) Applied pressure and temperature boundary conditions at the top and the bottom of the model(ie Dirichlet type and Neumann type) as well as the initial condition of the pressure and temperature earth gradients are shown A no-flowboundary condition is set to the lateral boundaries of the model The tested configuration of the production and injection sites (separatedhorizontally by a distance of ca 2 km) is highlighted by the refinement in the two-dimensional mesh

32 Boundary Conditions Temperature and pressure bound-ary conditions are summarized in Figure 5 In both sce-narios temperature and pressure distributions at the topwere assumed to be time invariant A fixed value of 15∘C(ie Dirichlet type) corresponding to the average annualtemperature of the area and an atmospheric pressure valueof 1 bar (ie Dirichlet type) were setThe implicit assumptionis that the groundwater table and the ground surface coincide[23 24] Outside the reservoir area temperature and pressureat the bottom boundary nodes were fixed too (ie Dirichlettype) The chosen values were calculated according to theaverage geothermal and pressure gradients of 03∘C10m and1 bar10m respectively (Figure 5) On the other hand giventhe anomalous geothermal gradient (17ndash21∘C10m [24]) inthe area of the buried structural high an incoming heat-fluxof 0256Wm2 (ie Neumann type) was applied at the nodeson bottom boundary below the reservoir area (Figure 5)

A no-mass flow conditionwas imposed over all the lateralboundaries (ie adiabatic and impermeable boundaries) Assaid above the large distance between the grid boundariesand the reservoir area guarantees that applied boundaryconditions do not affect the field behavior

The ldquonatural state simulationrdquo was performed to deter-mine the present-day reservoir condition without any fluidextractioninjection scenarios To let the system reach the

present-day anomalous temperature field the simulationcovers a period of 1 million years To verify the ldquonaturalstate simulationrdquo the spatial distribution of the simulatedtemperature was compared with the measured thermometricvertical profiles in correspondence to 3 geothermal wells(Alfina002 Alfina015 and RAI01 see Figure 1)

To simulate field production and to predict the futuresystem evolution pressure and temperature boundary con-ditions remained those applied for the ldquonatural state simula-tionrdquo A reasonable configuration of 5 production and 4 injec-tion wells separated horizontally by a distance of ca 2 km[24] was inserted in the ldquoexploitation process simulationrdquomodel (see Figures 1 and 5) A hypothetical 50-year produc-tion and injection time span with a flow rate of 1050 th waschosen following Buonasorte et al [24]Marini et al [69] andColucci and Guandalini [25] Starting from this productionscenario a flow rate of 210 th for each production well wasapplied At each injection well a constant injection temper-ature (ie Dirichlet type boundary condition) of 80∘C anda 2625 th injection rate were applied [48] These boundaryconditions distributed over the nodes of the active lengthof the productioninjection wells (ca 300 meters discretizedwith 12 nodes) were set as time-dependent At the end ofthe 50-year simulation run the wells boundary conditionswere removed and the simulation ran for an additional 10000

8 Geofluids

Table 1 Hydraulic and thermal parameters of the lithostratigraphic units involved in the natural state simulation Values are taken fromliterature [23ndash25 30 31 57 61ndash63 65 70] For the unit name the added specification in and out are used for formations stacked into ((4b)(5b) and (6b)) or outside ((4a) (5a) and (6a)) the proper geothermal reservoir respectively

Unit Density Porosity Permeability Compressibility Th conductivity Specific heatkgm3 m2 Paminus1 Wm∘C Jkg∘C

(1) Volcanic 2200 5 1 lowast 10minus18 1 lowast 10minus10 2 1000(2) Neoautochthonous 2400 30 1 lowast 10minus18 1 lowast 10minus10 24 1000(3) Ligurian 2400 055 1 lowast 10minus18 1 lowast 10minus10 24 833(4a) Scaglia out 2400 1 15 lowast 10minus17 12 lowast 10minus10 21 1000(4b) Scaglia in 2400 1 1 lowast 10minus15 12 lowast 10minus10 21 1000(5a) Tuscan nappe out 2660 6 15 lowast 10minus17 25 lowast 10minus10 24 836(5b) Tuscan nappe in 2660 6 1 lowast 10minus14 25 lowast 10minus10 24 836(6a) Umbria nappe out 2660 6 15 lowast 10minus17 25 lowast 10minus10 24 836(6b) Umbria nappe in 2660 6 198 lowast 10minus15 25 lowast 10minus10 24 836(7) Fault 2660 15 1 lowast 10minus18 1 lowast 10minus10 2 1000

years to investigate the recovery time and to test the technicalsustainability of geothermal power production

33 Initial Conditions In preparation for the dynamic reser-voir simulation initial reservoir conditions have to be deter-mined These initial conditions include both the geothermalgradient and the fluid pressure gradient (ie when advec-tionconvection is not involved) For this purpose this initial-ization phase of the natural state wasmodeled as a steady stateconditionwithout the incoming heat-flux at the bottomof thereservoirThe temperature and pressure boundary conditionsand model internal partitioning were set as described aboveIn this steady state initialization temperature and pressureeffects on fluid density and viscosity were neglected

The values of the petrophysical parameters of the involvedlithostratigraphic units (Table 1) were derived from availabledata for the area [23ndash25 30 31 57 61ndash63 65 70] Default val-ues for thermal conductivity of water (065WmK) and heatcapacity of water (42MJm3K) were usedThis initializationresulted in a temperature field with values ranging from 15∘Cto 160∘C at the ground surface and the bottom boundaryrespectively (Figure 6(a)) Fluid pressure ranges from 1 barat the ground surface to 491 bar at the model bottom

4 Natural State Simulation

41 Model Definition The natural state simulation aimedto define the present-day unexploited thermofluid dynamicconditions inside the geothermal reservoir including theadvectiveconvective fluid motion Simulation started byapplying initial conditions defined as above As commonpractice the natural state simulations of geothermal fieldsrequire a long simulation time so as to attain pressure andtemperature stabilization in the reservoir [18 66 71 72]Therefore a 1Ma simulation time has been chosen neglectingeffects of past climate change or transient effects in the rocksand representing a generic geologic period The performedtransient simulation adopted a maximum time step size of500 years This time step coincides with the one used toupdate the fluid density and viscosity values as a function

of calculated pressure and temperature Applied boundaryconditions remained the same presented above

Regarding the assignment of required petrophysicalparameters the reservoir units were distinguished betweenthose falling inside and outside the proper geothermal reser-voir (see Figure 4) The latter were initialized with a value ofpermeability equal to 15 lowast 10minus17m2 while the remaining re-servoir units preserved their typical fractured limestone per-meability values derived from the literature works and rang-ing from 10ndash14 to 10ndash15m2 (Table 1) A very low permeabilityvalue of 10ndash18m2 adopted for the overlaying sealing unitsallowedmodeling their impervious behavior A compressibil-ity value of 10minus10Paminus1 slightly lower compared the one usedfor the reservoir units (ie 12ndash25 lowast 10minus10 Paminus1 Table 1) wasassigned to these formations This reduced compressibilityallows maintaining the fluid pressure as simulated in theprevious stationary system initialization phase avoiding afluid pressure rise due to temperature increase The completeset of applied hydraulic and thermal parameters is given inTable 1

42 Results of the Natural State Simulation Results of the3D convective flows are shown in Figure 6 for three dif-ferent simulation times (ie 0 20000 and 125000 years)From the initial conductive temperature field equal to theaverage geothermal gradient of 03∘C10m (Figure 6(a)) avery efficient convective circulation develops only into thegeothermal reservoir units ((4b) (5b) and (6b) as listed inTable 1) This resulted in a gradual increase of temperaturevalues in this area while outside the producing units thepressure and temperature fields showed a full correspondenceto those obtained at the end of the previous stationary systeminitialization Fluid circulates in form of rolls and exhibitsmulticellular convective patterns which start oscillating afterca 20000 years of simulation time (Figure 6(b))This impliessharper inherent gradients and continuous creation anddisappearance of convective plumes patternsWithin the pro-ducing area three elongated convective cells stretched overthe entire geothermal reservoir (Figure 6(b)) The observed

Geofluids 9

RAI01 Alfina002

Alfina015

15 40 60 80 100 120 140 160Temperature (degC)

XY

Z

(a) 0 years

RAI01 Alfina002

Alfina015

Temperature (degC)

XY

Z 15 50 100 150 200 263

(b) 20000 years

RAI01 Alfina002

Alfina015

XY

Z

Temperature (degC)15 50 100 150 200 263

(c) 125000 years

Figure 6 Temperature field resulting from the transient natural state simulation The three wells (RAI01 Alfina015 and Alfina002 see alsoFigure 1) for which the available temperature logs were used to identify the reservoir present-day thermal state are shown Three differentsimulation times are presented (a) 0 years initial temperature field equal to the average earth gradient of 03∘C10m (b) 20000 yearsbeginning of the oscillating multicellular convective regime confined in the reservoir units and (c) 125000 years best-fitting time stepresulting in a good match between simulated and real thermometric data for the 3 evaluated wells (see Figure 7)

cellular motion consists of multiple central up-flows with afluid velocity in the range of 2ndash4 lowast 10minus8ms and associatedlateral down-flows The strong convective behavior allowscold infiltrating groundwater to reach basement depthswhereit gets heated before starting its upward migration to the topof the geothermal reservoir Comparing the results of thenatural state simulation along 1D profiles with real surveyedthermal profiles it is possible to identify the time instantfor which the model fits the real reservoir conditions The

identification of the best-fitting simulated temperature pro-files was performed through an iterative manual process bycomparing computed 1D profiles against temperature profilesat 3 geothermal wells (Alfina002 RAI01 and Alfina015 seeFigures 1 and 3) The attained best fitting occurs at the125000-year simulation time (Figure 6(c)) for all the threegeothermal wells At that time the pattern of the threeelongated convective cells is highlighted by a sharp differencein temperature between raising and sinking fluids Velocity of

10 Geofluids

50 100 150 2000Temperature (∘C)

50 100 150 2000Temperature (∘C)

50 100 150 200 2500Temperature (∘C)

MeasuredOpenGeoSys 125k yearsFEFLOW 230k years

Alfina002 Alfina015 RAI01

Reservoir depthReservoir depth

minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)

Figure 7 Results of the natural state simulation Comparison between best-fittingOpenGeoSys computed temperature profiles (125000 yearsof simulation green curves) best-fitting FEFLOW computed temperature profiles (230000 years of simulation blue curves) and available realthermometric data (red curves see Figure 3) Location of the selected wells is reported in Figures 1 and 6 In the plotted thermal logs thedepth of the reservoir top is highlighted A clear thermal inversion can be seen as soon as the reservoir units are crossed (ie minus500m aslfor Alfina002 well minus1050m asl for Alfina015 well and minus2000m asl for RAI01 well) This agrees with the stepped shape of the measureddeep temperature profile of Alfina015 well and supports the hypothesis of a highly convective behavior of the reservoir

the modeled convective cells rises to ca 7 lowast 10minus8ms whilemaximum fluid temperature reaches 263∘C

The sigmoidal shape of the temperature profiles suggeststhe occurrence of the highly convective flow (Figure 7) Infact all the three simulated profiles exhibit a clear thermalinversion as soon as the reservoir depth is reached (caminus500m asl for the Alfina002 well ca minus1000m asl for theAlfina015 well and ca minus2000m asl for the RAI01 well) Inthe upper 2 km of the temperature profiles (119879 lt 150∘C con-ductive regime) the difference between simulated and mea-sured values is at maximum 10∘C (see Figure 7) A compari-son between simulated andmeasured deep reservoir temper-ature values (119879 gt 150∘C convective regime) was possibleonly for the Alfina015 well representative of almost the entirethickness of the model The computed profile in correspon-dence to the Alfina015 well position shows a well-developedtrend with an almost constant temperature down to aboutminus3500m asl This can only be associated with the presenceof a convective cell A good fitting of the Alfina015 profiletemperature was obtained by slightly shifting the samplingprofile location of a fewmeters so that it hits upward buoyantflow FEFLOWandOGSmodels exhibit similar temperature-depth profiles in all wells but at different simulation time(125000 versus 230000 years see Discussion) Differences intemperature values are observed at maximum depth where

convection is dominant and controls the thermal evolutionof the system (Figure 7)

The computed best-fitting natural state temperature fieldformed the initial condition for the following dynamicreservoir simulations of the effects induced by the productionprocess

5 Exploitation Process Simulation

51 Model Definition Once a satisfactory match for thenatural state is accomplished a realistic scenario was set upfor the future exploitation of the CG-TA geothermal fieldthrough a 5MWe pilot doublet power plant

To achieve this the chosen configuration (see Figures 1and 5 [24]) of 5 production wells (CG1 CG1A CG2 CG3and CG3A) and 4 injection wells (CG14 CG14A CG14Band CG14C) was inserted in the model The production wellsextract the geothermal fluids from the uppermost portion(fromminus300 tominus700m asl) of the reservoir unitsThe extrac-tion depth range depends on the well position relatively tothe top of the producing areaThe injection of the 80∘C fluidat the above described rate was designed at a depth rangingbetween minus1350 and minus1550m asl For both production andinjection sites the well active length was fixed at 300 meters

Geofluids 11

35 403025 45 5020151050Time (yrs)

120125130135140145150155

Pres

sure

(bar

)Production wells field exploitation

CG2 wellCG3 well

(a)

35 403025 45 5020151050Time (yrs)

Injection wells field exploitation

CG14A wellCG14B well

220225230235240245250255

Pres

sure

(bar

)

(b)

120125130135140145150155

Pres

sure

(bar

)

Production wells full simulation time

CG2 wellCG3 well

450 500150 250200 300 350 40050 1000Time (yrs)

(c)

Injection wells full simulation time


220225230235240245250255

Pres

sure

(bar

)

450 500150 250200 300 350 40050 1000Time (yrs)

(d)

Figure 8 Evolution of well pressures during the exploitation process simulation at 2 selected production (CG2 and CG3 see Figure 1) and 2injection (CG14A and CG14B see Figure 1) wells (a) and (b) refer to the 50-year simulation time and (c) and (d) to the 10000-year recoveringtime The initial 500 years are shown in the full simulation time plots ((c) and (d)) as full recovery is reached This allows better visualizationof the transition between the field exploitation and the quick reestablishment of the initial undisturbed pressures

Pressure and temperature boundary conditions werethose described for the exploitation process simulation (seeboundary conditions Figure 5) Initial conditions mimickingthe present-day distribution of both temperature and pres-sure field were imported from the calculated best-fitting timestep (ie 125000 years of simulation time) of the previouslyperformed natural state simulation The exploitation timelasted 50 years and total simulation time of 10000 years so asto evaluate the field long-term effects induced by productionprocess

52 Field Exploitation The evolution of well pressure overtime computed at a node with depth close to the well bottomshowed that the maximum differences relatively to the initialpressure field were reached at the end of the productiontime (ie after 50 years of simulation) In more detail asshown in Figure 8(a) for wells CG2 and CG3 the productionwells realized a depressurization in the 15ndash17 bar range atthe end of the first year of simulation and then stabilizedto an averaged value of 19 bar at the end of the productiontime This pressure variation corresponds to approximately12ndash14 of the initial pressure values (from 120 to 150 bardepending on the considered well) in the production wellsAt the end of the exploitation of the geothermal field (ie

after 50 years) no further fluid extraction occurred and theproduction wells exhibited a fast recovery The monitoredpressures raised back to the initial values in less than 100 yearsfor the whole production site (see Figure 8(c) for the wellsCG2 and CG3)

On the other hand at the injection site injected waterresulted in strong overpressures rising quickly in the firstyears (ie around 14ndash16 bar) to stabilize to an average valueof 20 bar after 50 years of simulation (see Figure 8(b) forwells CG14A and CG14B) These overpressures correspondto approximately 7ndash10 of the initial pressure field (from225 to 240 bar for all the wells) recorded in the injectionwells At the end of the production time in the same way asfor the production wells pressure values recovered quicklyto the initial undisturbed ones (see Figure 8(d)) Thereforecomparing model pressure distribution at the beginning(natural state) and at the end of the simulation (ie after10000 years) no significant variations could be observed

The evolution of temperature over time for both pro-duction and injection wells is plotted in Figure 9 Duringsystem exploitation the recorded temperature at the produc-tion wells exhibited a progressive increase over time (seeFigure 9(a) for wells CG2 and CG1A)The difference betweenonset and end of production (ie after 50 years) temperatures

12 Geofluids

Production wells field exploitation

140

144

148

152

156

160Te

mpe

ratu

re (∘

C)

4510 15 20 25 30 35 405 500Time (yrs)

CG2 wellCG1A well

(a)

4510 15 20 25 30 35 405 500Time (yrs)

CG14C wellCG14 well

708090

100110120130140

Tem

pera

ture

(∘C)


(b)


CG2 wellCG1A well

144

146

148

150

152

154

156

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)

(c)


CG14C wellCG14 well

2000 4000 6000 8000 100000Time (yrs)

708090

100110120130140

Tem

pera

ture

(∘C)

(d)

Production wells extended simulation time

CG2 wellCG1A well

5000 10000 15000 20000 25000 300000Time (yrs)

Restart of convective oscillations

1440

1460

1480

1500

1520

1540

1560

Tem

pera

ture

(∘C)

(e)

Figure 9 Evolution of well temperatures during the exploitation process simulation at 2 selected production (CG2 and CG1A see Figure 1)and 2 injection (CG14 and CG14C see Figure 1) wells (a) and (b) refer to 50 years of exploitation process and (c) and (d) to the following10000 years of recovering (e) Temperature evolution at the production wells (CG2 and CG1A) over the extended simulation time of 30000years

varies from 25∘C for CG2 well to a maximum value of 95∘Cfor CG1 well This increase in temperature resulted from thedirect extraction of fluids from within a very strong convec-tive system in the inner portion of the reservoir Hence froma thermal point of view this analysis showed no interferenceeffects between injection and production sites

At the end of the phase of exploitation (Figure 9(c))the recorded temperatures at production wells exhibited twodifferent behaviors depending on the position of the wellrelatively to the generated convective cells For example in

the CG1A well the simulated temperature slowly decreasedafter the first 50 years of simulation time and recovered theinitial undisturbed values in about 1000 years By contrastthe recorded temperature in the CG2 well firstly decreasedto the initial value and then followed a gently increasingtrend (ca 2∘C at the end of 10000 years simulation seeFigure 9(c)) To investigate further this behavior simulationtime was extended to 30000 years (Figure 9(e)) It turned outthat for wells located close to the convective cell (eg CG2well) the recorded temperature exhibited strong convective

Geofluids 13

80∘C isosurface

Injection siteProduction site

15 50 100 150 200 269Temperature (degC)

XY

Z

1 km

1km

80 ∘C isosurface

(a)

(b)

Figure 10 (a) Perspective view of the temperature field and of the 80∘C isosurface (ie reinjected fluid temperature) at the end of the 50-year exploitation stage Location and depth of the production and the injection wells are shown (b) Evaluation of the influence area of theinjection wells obtained by representing the 80∘C ldquocold-waterrdquo front (ie isosurface) around the injection wells at the end of the 50-year fieldexploitation

oscillations starting after 5000 years from the end of pro-duction and preventing the stabilization to the initial tem-perature values (see Figure 9(e)) This behavior was relatedto the evolution of the convection regime and to the patternof multiple positive thermal anomalies

Fluid temperature in the injection area slowly decreasedover time reaching the injected value of 80∘C at the end of theproduction time (see Figure 9(b) for wells CG14 and CG14C)At the end of exploitation after 50 years of simulation timetemperatures in the surrounding of the injected wells recov-ered the initial values after ca 2000ndash3000 years (seeFigure 9(c))

To evaluate the thermal response of the CG-TA reservoirto the production process the influence area of the ldquocold-waterrdquo front was investigated (Figure 10) At the end of theproduction time the 80∘C isosurface around the four injec-tion wells covered a subspherical volume with ca 1 km indiameter (Figure 10(b)) Therefore the tested horizontal dis-tance of about 2 km between the production and injectionsites fully excluded the hypothesis of a thermal breakthrough

6 Discussion

Within the present work we set up an accurate hydrothermalmodel to recreate the highly convective behavior of theCG-TA reservoir and then simulate the exploitation of thisundeveloped geothermal fieldA general procedure formodelcalibration was applied [25 35 73ndash75] consisting of a naturalstate modeling followed by an exploitation process simulation

The above described natural state simulation resulted ina good match between simulated (via the OGS code) andmeasured temperature profiles after ca 125000 years of simu-lation time (see Figures 6(c) and 7) To analyze the tempera-ture field at the best-fitting simulation time (125000 yearsFigure 11) the OGS model was sliced with a vertical planealong the E-Waxis and passing through theAlfina015well (A-A1015840 section in Figures 11(a) 11(b) and 11(c)) Two convectiveplumes were recognized within the reservoir (Figure 11(c))Different vertical temperature profiles were extracted alongthis cross-section plane at different relative positions with

14 Geofluids

A

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

500

1000

Elev

atio

n (m

asl

)

50 100 150 200 2500Temperature (

∘C)

Alfina015AxialIntersecting

OutsideInterplumeMeasured

minus4000

minus3000

minus2000

minus1000

minus500

2001751501251007550250

Tem

pera

ture

(∘C)

0 7500 15000 22500Distance along x-axis (E-W) (m)

3000m asl

(a)

(b)

(d)

(e)(c)

Figure 11 Analysis of the temperature distribution at the best-fitting time as from the OGS model (a) oblique view of the model and thechose sampling plane position (b) cross section of the model with the material limits the relative position of the reservoir and of the verticaland horizontal sampling profiles (c) temperature field at 125000 years of simulation time with evidence of the convective plumes developedwithin the reservoir (d) and (e) vertical and horizontal profiles of temperature Grey box in (e) shows the lateral limits of the reservoir

respect to the convective plumes (ie interplume or in-between the two interacting plumes axial or along the majorplume axis intersecting or crossing the upper plume headoutside or in a portion not strongly affected by a convecting

plume Figure 11(d)) An increase in the conductive temper-ature field of the sealing units (ie profile portion above thecap rockreservoir contact elevation ranging between minus500and minus1000m asl depending on well position) is observed

Geofluids 15

moving toward the axis of the plume (Figures 11(c) and 11(d))Within the reservoir a thermal inversion characterizes thetemperature profiles which cut the main plume laterally (ieinterplume intersecting and Alfina015 profiles) The sigmoi-dal shape of the temperature vertical profiles is similar to theone observed in many other convection-dominated geother-mal systems for which comparable analyses were performed[18 22 43 47 76 77]

Multiple horizontal temperature profiles along A-A1015840(Figure 11(e)) cross section were extracted at different depths(ie minus4000 minus3000 minus2000 minus1000 minus500 0 and 300m asl)The deepest profiles clearly showed two positive thermalanomalies with values reaching more than 200∘C in corre-spondence to the plumes axis The shallower profiles show aprogressive merging of the two plumes

Once the unexploited present-day temperature and pres-sure fields are determined the computed natural state wasused as initial condition to simulate field production andthe future system evolution The highly convective behaviorof the system was suggested by the temperature graphs ofthe production wells in Figure 9(a) From these results weconclude that the thermal breakthrough was prevented astestified by the progressive increase in the recorded produc-tion site temperatures during the exploitation simulationMoreover the exploitation process induced only very smalllong-term changes with respect to the natural state of thegeothermal system In fact at the end of the production time(ie after 50 years of simulation time) temperature in theproductionwells located close to the convective cell (eg CG2well) exhibits strong convective oscillations following theunexploited behaviormodeled in the natural state simulationDarcy velocity of such convective cells stands in the range of75ndash85 lowast 10minus8ms therefore close to the preexploitation one

The performance of the OGS code at modeling the con-vective flow within the geothermal system has been testedagainst the FEFLOW code The two codes implemented thesame equations of state OGS and FEFLOW results show thatthe calculated patterns were qualitatively similar (eg multi-cellular convective fluid motion and velocities of convectivecells) while differences in the calculated values existed (egbest-fitting time step in the natural state simulation absolutepressure and temperature values during exploitation)

Results of the FEFLOW and OGS simulation are plot-ted in Figure 7 The iterative manual identification of thebest-fitting time step resulted in a good matching betweenFEFLOW simulated and real thermometric data around230000 years of simulation time Even if a quite large timegap characterized the reservoir present-day situation mod-eled with the two software programs (ie best-fitting at125000 years of simulation time for OGS and 230000 forFEFLOW) the simulated vertical profiles perfectly over-lapped for the entire depth of Alfina002 and Alfina015 wellsAs for the RAI01 well a good match between the two testedsoftware programs is observed in the shallower portion ofthe thermal logs (ie cover and impermeable units andconductive pattern) As soon as the reservoir depth is reached(ie minus2000m asl) convection is dominant As a resultthe simulated patterns can highly oscillate leading to largertemperature differences at selected simulation time steps (ca

50∘C at model bottom) At the best-fitting simulation timein the shallower portion of the vertical temperature profiles(119879 lt 150∘C) the difference between real measured data andFEFLOW simulated values stands in the range of 5∘C (seeFigure 7) This difference increases in the deeper portion ofthe temperature logs (119879 gt 150∘C) due to the highly convectiveflow as previously explained After 230000 years of simula-tion time FEFLOW convective cells exhibited a maximumvelocity of ca 136lowast10minus7ms and temperature values reaching280∘C

Starting from the present-day unexploited temperatureand pressure fields the same production scenario was simu-lated with FEFLOWThe results of pressure and temperatureversus simulation time for both production and injectionwells are plotted in Figure 12 FEFLOW returned a trend veryclose to the one by OGS for both pressure and temperaturetime evolution It is worth pointing out that the gap in thepressure values (sim15 bar Figures 12(b) and 12(d)) is due tothe fact that the two codes started from slightly differentinitial pressure fields and thus the recovery process stabilizesto these initial undisturbed values Furthermore the appliedinitial pressure and temperature fields were defined onthe natural state condition identified only by the availablethermal logs Therefore model constrains were only appliedto temperature while missing any present-day pressure dataAs the two software programs started from the same initialtemperature values identified in the natural state simulationthe time evolution during the field exploitation process isperfectly overlapped (sim1∘C gap see Figure 12(e)) Moreoverat the end of field production FEFLOW exhibits the sameconvective oscillations in the productive wells as alreadyobserved in the OGS results (Figure 12(g))

Finally the areal extent of the 80∘C ldquocold-waterrdquo front wasevaluated in FEFLOW as in OGSThe 80∘C isosurface propa-gated away from the injectionwells and reached itsmaximumextent at the end of the production time (ie 50 years) Againa slightly irregular spherical shape ca 1 km in diameter wasobserved This confirms that the tested exploitation scenarioprevents the thermal breakthrough in the same way as shownby OGS simulation

7 Conclusions

The objectives of this study are to model the origin of thethermal anomaly observed in the CG-TA medium-enthalpygeothermal field to investigate the feasibility of geothermalexploitation and to test capabilities of different codes atmod-eling highly buoyant flows A fit-for-purpose 3D numericalmodel of the CG-TA geothermal system was built using theopen source OpenGeoSys (OGS) code and the commercialFEFLOW code Following a general procedure for geother-mal numerical models calibration the present-day highlyconvective unexploited (natural) state model preceded thesimulation of field production process Starting from a steadystate initialization of the reservoir a satisfactory naturalstate modeling was achieved with limited differences betweenmeasured and computed temperatures At higher depths asconvection is dominant strongmeasuredcalculated temper-ature discrepancies can be observedThemulticellular highly

16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)

OGS CG2 wellFEFLOW CG2 well

(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)

OGS CG14A wellFEFLOW CG14A well

(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)


(f)Production wells extended simulation time

146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)

Figure 12 Comparison between the OpenGeoSys (OGS) and the FEFLOWmodel results (a) (b) (c) and (d) pressure (CG2well see Figure 1for location) and (e) (f) (g) and (h) temperature (CG14 well see Figure 1 for location) evolution in time for both production and injectionsites (a) (b) (e) and (f) refer to the 50-year field exploitation and (c) (d) (g) and (h) to the full simulation time (ie 10000 years) Theinitial 500 years are shown in the full simulation time plots ((c) and (d)) as full recovery is reached

Geofluids 17

convective behavior (Darcy velocity of 7 lowast 10minus8ms) of thereservoir was successfully modeled in agreement with whatwas inferred by the extensive deep explorations campaignsperformed in the area

Simulation of the exploitation process covered a total timeinterval of 10000 years with fluid extraction and injectionlimited to the initial 50 years Simulations showed that onlysmall changes were induced by the exploitation of the geo-thermal system (producing well temperature increase be-tween 25 and 95∘C after 50 years) and no thermal break-through occurs Full recovery occurs in about one thousandyears due to the highly convective behavior of the reservoirThe good agreement betweenmeasured and simulated resultsfor the natural state allowed a confident prediction of thereservoir response to future exploitation

These concluding remarks were also sustained by thequalitatively similar calculated patterns resulting from theFEFLOW performed simulation Even if a time discrepancyin the identification of the present-day natural state occursbetween FEFLOW andOGS the convective system behaviorthe fitting between simulated and real thermal data and thereservoir response to the tested exploitation scenario are fullycomparable

Such models support the understanding of reservoirbehavior and are critical to optimal reservoir managementand sustainable utilization Their reliability could be im-proved by integrating data from new superficial and deep ex-plorations and at the same time they can support the plan-ning of new investigations well drilling and the design ofexploitation steps aimed at the usage of geothermal energyin the Caste Giorgio-Torre Alfina area

Disclosure

This work represents the continuation of a project that wasintroduced in its early stage with the oral presentation at9th EGUGeneral Assembly (Geophysical Research AbstractsVol 19 EGU2017-16968)

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

This research originated from a collaboration between Uni-versity of Milano-Bicocca and Ricerca di Sistema Energetico(RSE) The authors acknowledge RSE for providing the datain particular Fabio Moia who encouraged this cooperationThey also greatly acknowledgeRobertoGuandalini andAgateGiordano from the RSE research group for discussing withthem themodelling approach and for the helpful suggestionsin the construction and the calibration of the model

References

[1] L Rybach ldquoIngrid Stober und Kurt Bucher Geothermierdquo uwfUmweltWirtschaftsForum vol 20 no 2-4 pp 197-197 2012

[2] M H Dickson andM Fanelli ldquoSmall Geothermal Resources AReviewrdquo Energy Sources vol 16 no 3 pp 349ndash376 2007

[3] International Energy Agency ldquoEnergy statistics of Non-OECDcountriesrdquo Tech rep 2009

[4] G P Eaton R L Christiansen H M Iyer et al ldquoMagma be-neath Yellowstone National Parkrdquo Science vol 188 no 4190 pp787ndash796 1975

[5] P Morgan D D Blackwell R E Spafford and R B SmithldquoHeat flow measurements in Yellowstone Lake and the thermalstructure of the Yellowstone Calderardquo Journal of GeophysicalResearch Atmospheres vol 82 no 26 pp 3719ndash3732 1977

[6] I Lucchitta ldquoRole of heat and detachment in continental exten-sion as viewed from the eastern basin and range province inArizonardquo Tectonophysics vol 174 no 1-2 pp 77ndash114 1990

[7] L W Younker P W Kasameyer and J D Tewhey ldquoGeologi-cal geophysical and thermal characteristics of the Salton SeaGeothermal Field Californiardquo Journal of Volcanology and Geo-thermal Research vol 12 no 3-4 pp 221ndash258 1982

[8] D Ravnik D RajverM Poljak andM Zivcic ldquoOverview of thegeothermal field of Slovenia in the area between the Alps theDinarides and the Pannonian basinrdquo Tectonophysics vol 250no 1-3 pp 135ndash149 1995

[9] D Werner and H Kahle ldquoA geophysical study of the Rhine-grabenmdash I Kinematics and geothermicsrdquoTheGeophysical Jour-nal of the Royal Astronomical Society vol 62 no 3 pp 617ndash6291980

[10] J P BrunM-A Gutscher and dekorp-ecors teams ldquoDeep crus-tal structure of the Rhine Graben from dekorp-ecors seismicreflection data A summaryrdquo Tectonophysics vol 208 no 1-3pp 139ndash147 1992

[11] S Bellani A Brogi A Lazzarotto D Liotta and G RanallildquoHeat flow deep temperatures and extensional structures in theLarderello Geothermal Field (Italy) Constraints on geothermalfluid flowrdquo Journal of Volcanology and Geothermal Research vol132 no 1 pp 15ndash29 2004

[12] A Barelli R Bertani G Cappetti and A Ceccarelli ldquoAn updateon Travale Radicondoli geothermal fieldrdquo in Proceedings of theProceedingsWorldGeothermal Congress pp 1581ndash1586 Florence Italy 1995

[13] A Barelli G Cappetti and G Stefani ldquoOptimum exploitationstrategy at Larderello-Valle Secolordquo in Proceedings of the Pro-ceedings World Geothermal Congress pp 1779ndash1783 Florence Italy 1995

[14] A Barelli G Cappetti and G Stefani ldquoResults of deep drillingin the LarderelloTravaleRadicondoli geothermal areardquo in Pro-ceedings of the Proceedings World Geothermal Congress pp1275ndash1278 Florence Italy 1995

[15] A Barelli G Bertini G Buonasorte G Cappetti and A Fior-delisi ldquoRecent deep exploration results at the margins of theLarderelloTravale geothermal systemrdquo in Proceedings of the Pro-ceedings World Geothermal Congress pp 965ndash970 Kyushu-Tohoku Japan 2000

[16] F Batini A Brogi A Lazzarotto D Liotta and E PandelildquoGeological features of Larderello-Travale and Mt Amiata geo-thermal areas (southern Tuscany Italy)rdquo Episodes vol 26 no 3pp 239ndash244 2003

[17] G N Tiwari and M K Ghosal ldquoRenewable energy resourcesBasic principles and applicationsrdquo in Proceedings of the Interna-tional Journal of Industrial Engineering Computations vol 3 pp649ndash662 2005

18 Geofluids

[18] P Romagnoli A Arias A Barelli M Cei and M Casini ldquoAnupdated numerical model of the Larderello-Travale geothermalsystem Italyrdquo Geothermics vol 39 no 4 pp 292ndash313 2010

[19] L Carmignani F A Decandia P L Fantozzi A LazzarottoD Liotta and M Meccheri ldquoTertiary extensional tectonics inTuscany (Northern Apennines Italy)rdquo Tectonophysics vol 238no 1-4 pp 295ndash315 1994

[20] C Brunet P Monie L Jolivet and J-P Cadet ldquoMigration ofcompression and extension in the Tyrrhenian Sea insights from40Ar39Ar ages on micas along a transect from Corsica toTuscanyrdquo Tectonophysics vol 321 no 1 pp 127ndash155 2000

[21] B Della Vedova S Bellani G Pellis and P Squarci ldquoDeeptemperatures and surface heat flow distributionrdquo in Anatomyof an orogen the Apennines and adjacent Mediterranean basinspp 65ndash76 2001

[22] B Della Vedova C Vecellio S Bellani and U Tinivella ldquoTher-mal modelling of the Larderello geothermal field (TuscanyItaly)rdquo International Journal of Earth Sciences vol 97 no 2 pp317ndash332 2008

[23] R Cataldi and M Rendina ldquoRecent discovery of a new geo-thermal field in Italy Alfinardquo Geothermics vol 2 no 3-4 pp106ndash116 1973

[24] G Buonasorte R Cataldi A Ceccarelli et al ldquoRicerca ed esplo-razione nellrsquoarea geotermica di Torre Alfina (Lazio-Umbria)rdquo inBollettino della Societa Geologica Italiana vol 107 pp 265ndash3371988

[25] Colucci andGuandalini ldquoModelli geologici e simulazione num-erica di sistemi geotermicirdquo Rapporto di Ricerca di Sistema2014 httpdocrse-webitdocdoc-sfoglia15000985-31605415000985-316054html

[26] F Barberi G Buonasorte R Cioni et al ldquoPlio-Pleistocene geo-logical evolution of the geothermal area of Tuscany andLatiumrdquoMem Descr Carta Geol Ital vol 49 pp 77ndash133 1994

[27] CChiarabbaAAmato andA Fiordelisi ldquoUpper crustal tomo-graphic images of the Amiata-Vulsini geothermal region cen-tral Italyrdquo Journal of Geophysical Research Atmospheres vol 100no 3 pp 4053ndash4066 1995

[28] G Chiodini F Frondini and F Ponziani ldquoDeep structures andcarbon dioxide degassing in Central ItalyrdquoGeothermics vol 24no 1 pp 81ndash94 1995

[29] M Doveri M Lelli L Marini and B Raco ldquoRevision calibra-tion and application of the volume method to evaluate thegeothermal potential of some recent volcanic areas of LatiumItalyrdquo Geothermics vol 39 no 3 pp 260ndash269 2010

[30] M L Carapezza M Ranaldi A Gattuso N M Pagliuca and LTarchini ldquoThe sealing capacity of the cap rock above the TorreAlfina geothermal reservoir (Central Italy) revealed by soilCO2 flux investigationsrdquo Journal of Volcanology andGeothermalResearch vol 291 pp 25ndash34 2015

[31] G Buonasorte E Pandeli andA Fiordelisi ldquoTheAlfina 15Welldeep geological data from northern Latium (Torre Alfina geo-thermal area)rdquo Bollettino della Societa Geologica Italiana pp823ndash831 1991

[32] E U Antunez S K Sanyal A JMenzies et al ldquoForecastingwelland reservoir behavior using numerical simulation Uenotaigeothermal field Akita prefecture Japanrdquo in Proceedings of the1990 International Symposium on Geothermal Energy pp 1255ndash1262 August 1990

[33] E U Antunez G S Bodvarsson andMAWalters ldquoNumericalsimulation study of the Northwest Geysers geothermal field acase study of the Coldwater Creek steamfieldrdquoGeothermics vol23 no 2 pp 127ndash141 1994

[34] M OrsquoSullivan B Barnett and Y Razali ldquoNumerical simulationof the Kamojang Geothermal Field Indonesiardquo in Proceedingsof the 1990 International Symposium on Geothermal Energy pp1317ndash1324 August 1990

[35] M J OrsquoSullivan K Pruess and M J Lippmann ldquoState of theart geothermal reservoir simulationrdquo Geothermics vol 30 no4 pp 395ndash429 2001

[36] M Hanano ldquoReservoir engineering studies of the matsukawageothermal field Japanrdquo in Proceedings of the 1992 AnnualMeeting of the Geothermal Resources Council pp 643ndash650October 1992

[37] M Hanano ldquoSimulation study of the Matsukawa geothermalreservoir Natural state and its response to exploitationrdquo Journalof Energy Resources Technology-Transactions of the ASME vol114 no 4 pp 309ndash314 1992

[38] G Axelsson and G Bjornsson ldquoDetailed three-dimensionalmodeling of the Botn hydrothermal system in N-Icelandrdquo inProceedings of the 18thWorkshop on Geothermal Reservoir Engi-neering pp 159ndash166 Stanford University Stanford California1993

[39] M Pham and A J Menzies ldquoResults from a field-wide num-erical model of the geysers geothermal field Californiardquo in Pro-ceedings of the 1993 AnnualMeeting on Utilities and GeothermalAn Emerging Partnership pp 259ndash265 October 1993

[40] M Pham A J Menzies S K Sanyal et al ldquoNumerical model-ing of the high-temperature geothermal system of AmatitlanGuatemalardquo in Proceedings of the 1996 Annual Meeting of theGeothermal Resources Council pp 833ndash838 October 1996

[41] R Bertani and G Cappetti ldquoNumerical simulation of the Mon-teverdi zone (western border of the Larderello geothermal fieldrdquoin Proceedings of the ProceedingsWorld Geothermal Congress 95pp 1735ndash1740 Florence 1995

[42] M A Antics ldquoComputer simulation of the Oradea geothermalreservoirrdquo in Proceedings of the 22nd Workshop on GeothermalReservoir Engineering pp 491ndash495 Stanford University Stan-ford Calif USA 1997

[43] P Fulignati P Marianelli A Sbrana and V Ciani ldquo3D geother-mal modelling of the mount amiata hydrothermal system inItalyrdquo Energies vol 7 no 11 pp 7434ndash7453 2014

[44] T Li S Shiozawa andMW McClure ldquoThermal breakthroughcalculations to optimize design of a multiple-stage EnhancedGeothermal Systemrdquo Geothermics vol 64 pp 455ndash465 2016

[45] M Caputo ldquoDiffusion of fluids in porous media with memoryrdquoGeothermics vol 28 no 1 pp 113ndash130 1999

[46] K Nicholson Geothermal fluids chemistry and explorationtechniques Springer Science amp Business Media 2012

[47] M G Blocher G Zimmermann I Moeck W Brandt AHassanzadegan and F Magri ldquo3D numerical modeling ofhydrothermal processes during the lifetime of a deep geother-mal reservoirrdquo Geofluids vol 10 no 3 pp 406ndash421 2010

[48] TW amp LKW Geotermia Italia SpA Impianto pilota geo-termico Castel Giorgio (TR) Progetto definitivo e programmalavori 2013 httpwwwvaminambienteitit-ITOggettiDoc-umentazione13731855Testo=20Progetto20e20Program-ma20Lavoriampamppagina=1form-cercaDocumentazione

[49] O Kolditz S Bauer L Bilke et al ldquoOpenGeoSys An open-source initiative for numerical simulation of thermo-hydro-mechanicalchemical (THMC) processes in porous mediardquoEnvironmental Earth Sciences vol 67 no 2 pp 589ndash599 2012

[50] H-J G Diersch Feflow Finite Element Modeling of Flow Massand Heat Transport in Porous and Fractured Media Springer-Verlag Berlin Heidelberg Berlin Germany 2014

Geofluids 19

[51] F A Decandia A Lazzarotto D Liotta L Cernobori and RNicolich ldquotraverse insights on post-collisional evolution ofNorthern ApenninesrdquoThe CROP vol 03 pp 427ndash439 1998

[52] D Liotta L Cernobori and R Nicolicl ldquoRestricted rifting andits coexistence with compressional structures Results from theCROP 3 traverse (northern Apennines Italy)rdquo Terra Nova vol10 no 1 pp 16ndash20 1998

[53] A Brogi A Lazzarotto D Liotta and G Ranalli ldquoExtensionalshear zones as imaged by reflection seismic lines The Lardellogeothermal field (central Italy)rdquoTectonophysics vol 363 no 1-2pp 127ndash139 2003

[54] A Brogi A Lazzarotto D Liotta et al ldquoCrustal structures in thegeothermal areas of southern Tuscany (Italy) Insights from theCROP 18 deep seismic reflection linesrdquo Journal of Volcanologyand Geothermal Research vol 148 no 1-2 pp 60ndash80 2005

[55] E Carminati and C Doglioni ldquoMediterranean tectonicsrdquo Ency-clopedia of Geology vol 2 pp 135ndash146 2005

[56] G Buonasorte A Fiordelisi E Pandeli U Rossi and F Solle-vanti ldquoStratigraphic correlations and structural setting of thepre- neoautochthonous sedimentary sequences of northernLatiumrdquo Periodico di Mineralogia vol 56 no 2-3 pp 111ndash1221987

[57] G Buonasorte G M Cameli A Fiordelisi M Parotto and IPerticone ldquoResults of geothermal exploration in Central Italy(Latium-Campania)rdquo in Proceedings of the In Proceedings of theWorld Geothermal Congress pp 18ndash31 Florence Italy 1995

[58] L Petracchini D Scrocca S Spagnesi and F Minelli ldquo3Dgeological modeling to support the assessment of conventionaland unconventional geothermal resources in the latium region(Central Italy)rdquo in Proceedings of the In World GeothermalCongress pp 19ndash25 2015

[59] AMinissale ldquoThe Larderello geothermal field a reviewrdquo Earth-Science Reviews vol 31 no 2 pp 133ndash151 1991

[60] F Rossetti C Faccenna L Jolivet R Funiciello F Tecce and CBrunet ldquoSyn- versus post-orogenic extensionThe case study ofGiglio Island (Northern Tyrrhenian Sea Italy)rdquo Tectonophysicsvol 304 no 1-2 pp 71ndash93 1999

[61] L D Nardi G Pieretti andM Rendina ldquoStratigrafia dei terreniperforati dai sondaggi ENEL nell9area geotermica di TorreAlfinardquo Bollettino della Societa Geologica Italiana vol 96 no3 pp 403ndash422 1977

[62] D Cosentino P Cipollari P Marsili and D Scrocca ldquoGeologyof the central Apennines A regional reviewrdquo Journal of theVirtual Explorer vol 36 2010

[63] G Vignaroli A Pinton A A De Benedetti et al ldquoStructuralcompartmentalisation of a geothermal system the Torre Alfinafield (central Italy)rdquo Tectonophysics vol 608 pp 482ndash498 2013

[64] D Piscopo M Gattiglio E Sacchi and E Destefanis ldquoTec-tonically-related fluid circulation in the san casciano dei bagni-sarteano area (m cetona ridge-southern tuscany) a coupledstructural and geochemical investigationrdquo Bollettino della Soci-eta Geologica Italiana vol 128 no 2 pp 575ndash586 2009

[65] A Costantini C Ghezzo and A Lazzarotto ldquoCarta geologicadellrsquoarea geotermica di Torre Alfina (prov di SienandashViterbondashTerni) Ente Nazionale per lrsquoEnergia Elettrica (ENEL Unit120572Nazionale Geotermica Pisa Cartografia SELCArdquo Carta geo-logica dellrsquoarea geotermica di Torre Alfina (prov di SienandashViterbondashTerni) Ente Nazionale per lrsquoEnergia Elettrica (ENELUnit120572 Nazionale Geotermica Pisa Cartografia SELCA 1984

[66] L Carmignani and A Lazzarotto ldquoCarta geologica della Tos-cana geological Map of Tuscany (Italyrdquo in Regione Toscana

Direzione delle Politiche Territoriali e Ambientali-Servizio geo-logico vol 1 Carta geologica della Toscana geological Map ofTuscany (Italy) 1 250000 Regione Toscana 2004

[67] F Magri N Inbar C Siebert E Rosenthal J Guttman andP Moller ldquoTransient simulations of large-scale hydrogeologicalprocesses causing temperature and salinity anomalies in theTiberias Basinrdquo Journal of Hydrology vol 520 pp 342ndash3552015

[68] EMS-IGroundwaterModeling System60 EnvironmentalMod-elingSystems Inchttpwwwaquaveocomsoftwaregms-ground-water-modeling-system-introduction 2006

[69] L Marini F Franceschini M Ghigliotti M Guidi and A Mer-la ldquoValutazione del potenziale geotermico nazionale ENEA-Geotermica Italiana Report for the Ministero dellIndustriardquo delCommercio e dellArtigianato 1993

[70] G Giordano A A De Benedetti A Diana et al ldquoThe ColliAlbani mafic caldera (Roma Italy) Stratigraphy structure andpetrologyrdquo Journal of Volcanology andGeothermal Research vol155 no 1-2 pp 49ndash80 2006

[71] E A Porras T Tanaka H Fujii and R Itoi ldquoNumerical model-ing of the Momotombo geothermal system Nicaraguardquo Geo-thermics vol 36 no 4 pp 304ndash329 2007

[72] E M Llanos S J Zarrouk and R A Hogarth ldquoNumeri-cal model of the Habanero geothermal reservoir AustraliardquoGeothermics vol 53 pp 308ndash319 2015

[73] M J Orsquosullivan ldquoGeothermal reservoir simulationrdquo Interna-tional Journal of Energy Research vol 9 no 3 pp 319ndash332 1985

[74] G S Bodvarsson K Pruess V Stefansson et al Natural statemodel of the Nesjavellir geothermal field Iceland (No SGP-TR-93-17) Lawrence Berkeley National Laboratory (LBNL)Earth Sciences Division Berkeley CA USA National EnergyAuthority of Iceland Reykjavik Iceland Reykjavik MunicipalDistrict Heating Service Reykjavik Iceland 1986

[75] K Pruess J S YWang and YW Tsang ldquoOn thermohydrologicconditions near high-level nuclear wastes emplaced in partiallysaturated fractured tuff 1 Simulation studies with explicitconsideration of fracture effectsrdquoWater Resources Research vol26 no 6 pp 1235ndash1248 1990

[76] B M Feather and R C M Malate ldquoNumerical modeling of theMita geothermal field Cerro BlancoGuatemalardquo inProceedingsof the In Proceedings of the Thirty-Eighth Workshop on Geother-mal Reservoir Engineering pp 11ndash13 Stanford University Stan-ford CA February 2013

[77] A Ebigbo J Niederau G Marquart et al ldquoInfluence of depthtemperature and structure of a crustal heat source on thegeothermal reservoirs of Tuscany numerical modelling andsensitivity studyrdquo Geothermal Energy vol 4 no 1 article no 52016

Hindawiwwwhindawicom Volume 2018

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Submit your manuscripts atwwwhindawicom

2 Geofluids

extremely high and variable surface heat-flux anomalies [2122] All these processes document a predominant heat trans-fermechanism by verticalmass flow which accumulates largeamount of geothermal resources at accessible depths in theupper crust Two geothermal fields in the area characterizedby heat flow values of up to 1000mWm2 (Larderello system)and 600mWm2 (Mt Amiata system) [11] are currentlyexploited for the production of electricity

Recently various projects were set up on a regional basisto investigate the geothermal potential of the Italian Tyrrhe-nian facing areas Moreover research and development ofnew exploitable geothermal fields have been encouraged bythe approval of specific decrees of law (ie Legislative Decreeof 11 February 2010 n 22 modified by Legislative Decree of3 March 2011 n 28 and Article 28 of Decree of Law of 18October 2012 n 179)

Among the identified promising areas the Castel Gior-gio-Torre Alfina field (CG-TA northern Latium Figure 1)is an example of an early explored and so far not exploitedmedium-enthalpy geothermal system [23ndash25] Detailed hy-drogeothermal data available for the selected area since early70s show that the CG-TA is a potential geothermal reservoirwith medium thermal characteristics (120∘Cndash210∘C) whosefluids (pressurized water and gas mainly CO

2) are hosted

in a fractured carbonate formation [24 26ndash30] Data fromthe deepest geothermal drilling in the area (Alfina015 wellmax depth minus4826m asl see Figure 1 for location) showa highly variable temperature gradient ranging between015∘C10m and 21∘C10m [31] Such a strong variation likelyindicates the presence of highly convective flow within thereservoir rocks This finding makes the CG-TA area suitablefor future exploitation through a new generation 5MWegeothermal pilot power plant Following the guidelines of theabove-mentioned Italian legislative decrees this exploitationproject is characterized by no gas emission to the atmosphereand total reinjection of the geothermal fluid in the sameproducing geological formation (ie geothermal well doubletsystem)

Planning of such challenging geothermal field exploita-tion projects requires an appropriate numerical modeling ofthe involved heat and fluid transfer processes In the last20ndash25 years models have been set up for more than 150geothermal fields worldwide [18 22 32ndash43]These numericalmodels allow us to define wellrsquos system design fracture pathsextraction rates and temperature of injected and producedthermal waters to interpret hydraulic tests or stimulationprocesses and to predict reservoir behavior during geother-mal power production Therefore they are mandatory tooptimize the productive capacity and the thermal break-through occurrence [1 44]

Mathematical modeling of a geothermal reservoir allowsreconstructing both the deep natural fluid circulation andphysicalchemical fluid characteristicsThis can be of interestat geothermal sites where high temperatures and strong cor-rosion caused by very acidic involved fluids occur In somecases the fluids may react chemically with the hosting rocksprecipitating minerals that diminish reservoir permeabilityby pores and fractures obstruction [45] These phenomena

create spatially variable patterns of mineralization and per-meability thus affecting the exploitation of the reservoir [4546]

Numerical modeling of exploited geothermal systemsshould include (i) a solid conceptual model of the reservoirgeology and structure (ii) the location and geometry of wellsand possible fractures systems and (iii) the parameterizationof hydraulic thermal mechanical and chemical (HTMC)properties of the reservoir and of the involved fluids [47]

The aim of the present study is to build the 3D numericalmodel of the deep medium-enthalpy CG-TA reservoir to re-produce the highly convective undisturbed present-day nat-ural state of the reservoir These results validated against thepressures and temperatures measured in geothermal wellsare afterward used to investigate the feasibility of a geother-mal power production configuration (ie injection and pro-duction wells) The analysis is performed on a hypothetical50-year operational life cycle adopting a well doublet systemat a 1050 th flow rate [48] The finite-element open sourcecode OpenGeoSys [49] is used to build the hydrothermal(HT) model As additional numerical constraint the resultsare compared against those obtained with the commercialfinite-element code FEFLOW [50]

First the hydrogeothermal data derived from geophysicalinvestigations and from geothermal wells are described andused to build a conceptual and numerical model of the CG-TAreservoirThen thenumerical approach based on theOpen-GeoSys software is given Results are obtained both at short-term (ie operational) and long-term (ie full reservoirrecovery) time scale Besides providing valuable guidelinesfor future exploitation of the CG-TA deep geothermalreservoir this study highlights the importance of field dataconstraints for the interpretation of numerical results of fluidprocesses in reservoir-scale systems

2 Reservoir Characterization

21 Regional Geological Setting The occurrence of medium-and high-enthalpy geothermal fields in central Italy islocalized along the Tyrrhenian margin of the Apennines(Figure 1) The complex geologic and tectonic settings ofthis area have been studied by several authors ([51ndash54] andreferences therein)

The present-day structural setting of the Tyrrhenian coastfacing regions represents a heritage of compressive and exten-sional geodynamic processes that began in the Oligocene(ie 30MaBP) with the Alpine-Apennine orogenesis [18 55]The compressive phase resulted in the formation of fold-and-thrust-belts and associated piggy-back basins with NNE-SSW oriented trend [56ndash58] Then the subsequent exten-sional phase due to the Tyrrhenian back-arc extensionresulted in the formation of NWndashSE tectonic basins and inthe crustal thinning with consequent upwelling of magmabodies and increased heat flow [18 21 22 59 60]

Due to the interplay of all these phenomena the geologicand structural settings of the area are quite complex andinvolve many different lithostratigraphic unitsThemain andmost widespread complexes from the shallower to the deeperones [18 25 61 62] (Figure 2) are namely

Geofluids 3

Si

Lo

Pd

Tu

Sa

ER

Ap

La

Ve

Ca

Cp

Ab

Bs

TST

Ma

Li

Um

FVG

Mo

AV

CG2

CG1A CG1CG3A

CG3

CG14CG14A


CG-TA field

Mt Cetona

A14A04

A02A15

A01A13A05

R01A07

G01bisG01

GC1B01

Ba19

(b)



Injection wells

B


(a)

5(km)

075(km)

Vulsini caldera

0 15

Tuscany

Latium

Um

bria

N

N

0 10














4 Geofluids


400

1000

2000

m plusmn 0

SSE

400

0

1000

2000

1

2

3

4

5

6

Volcanic complex


Ligurian complex

Scaglia complex



minus5000

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

(m)


0 1 2(km)




Geofluids 5


minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)

50 100 150 200 2500Temperature (∘C)









2flux was recorded



6 Geofluids



Volcanic complex



Scaglia complex in

Reservoir area


225 km

75km

25 km

5 km

13 kmXY

Z

Fault










Geofluids 7

Topographic surface

Reservoir area




03∘C10m

- 1 bar10m











8 Geofluids












Geofluids 9

RAI01 Alfina002

Alfina015


XY

Z

(a) 0 years

RAI01 Alfina002

Alfina015

Temperature (degC)

XY

Z 15 50 100 150 200 263

(b) 20000 years

RAI01 Alfina002

Alfina015

XY

Z


(c) 125000 years




10 Geofluids

50 100 150 2000Temperature (∘C)

50 100 150 2000Temperature (∘C)

50 100 150 200 2500Temperature (∘C)




minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)









Geofluids 11

35 403025 45 5020151050Time (yrs)

120125130135140145150155

Pres

sure

(bar


CG2 wellCG3 well

(a)

35 403025 45 5020151050Time (yrs)



220225230235240245250255

Pres

sure

(bar

)

(b)

120125130135140145150155

Pres

sure

(bar

)


CG2 wellCG3 well

450 500150 250200 300 350 40050 1000Time (yrs)

(c)



220225230235240245250255

Pres

sure

(bar

)

450 500150 250200 300 350 40050 1000Time (yrs)

(d)







12 Geofluids


140

144

148

152

156

160Te

mpe

ratu

re (∘

C)

4510 15 20 25 30 35 405 500Time (yrs)

CG2 wellCG1A well

(a)

4510 15 20 25 30 35 405 500Time (yrs)

CG14C wellCG14 well

708090

100110120130140

Tem

pera

ture

(∘C)


(b)


CG2 wellCG1A well

144

146

148

150

152

154

156

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)

(c)


CG14C wellCG14 well

2000 4000 6000 8000 100000Time (yrs)

708090

100110120130140

Tem

pera

ture

(∘C)

(d)


CG2 wellCG1A well

5000 10000 15000 20000 25000 300000Time (yrs)


1440

1460

1480

1500

1520

1540

1560

Tem

pera

ture

(∘C)

(e)





Geofluids 13

80∘C isosurface



XY

Z

1 km

1km

80 ∘C isosurface

(a)

(b)





6 Discussion



14 Geofluids

A

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

500

1000

Elev

atio

n (m

asl

)

50 100 150 200 2500Temperature (

∘C)



minus4000

minus3000

minus2000

minus1000

minus500

2001751501251007550250

Tem

pera

ture

(∘C)


3000m asl

(a)

(b)

(d)

(e)(c)




Geofluids 15









7 Conclusions


16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















Geofluids 3

Si

Lo

Pd

Tu

Sa

ER

Ap

La

Ve

Ca

Cp

Ab

Bs

TST

Ma

Li

Um

FVG

Mo

AV

CG2

CG1A CG1CG3A

CG3

CG14CG14A


CG-TA field

Mt Cetona

A14A04

A02A15

A01A13A05

R01A07

G01bisG01

GC1B01

Ba19

(b)



Injection wells

B


(a)

5(km)

075(km)

Vulsini caldera

0 15

Tuscany

Latium

Um

bria

N

N

0 10














4 Geofluids


400

1000

2000

m plusmn 0

SSE

400

0

1000

2000

1

2

3

4

5

6

Volcanic complex


Ligurian complex

Scaglia complex



minus5000

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

(m)


0 1 2(km)




Geofluids 5


minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)

50 100 150 200 2500Temperature (∘C)









2flux was recorded



6 Geofluids



Volcanic complex



Scaglia complex in

Reservoir area


225 km

75km

25 km

5 km

13 kmXY

Z

Fault










Geofluids 7

Topographic surface

Reservoir area




03∘C10m

- 1 bar10m











8 Geofluids












Geofluids 9

RAI01 Alfina002

Alfina015


XY

Z

(a) 0 years

RAI01 Alfina002

Alfina015

Temperature (degC)

XY

Z 15 50 100 150 200 263

(b) 20000 years

RAI01 Alfina002

Alfina015

XY

Z


(c) 125000 years




10 Geofluids

50 100 150 2000Temperature (∘C)

50 100 150 2000Temperature (∘C)

50 100 150 200 2500Temperature (∘C)




minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)









Geofluids 11

35 403025 45 5020151050Time (yrs)

120125130135140145150155

Pres

sure

(bar


CG2 wellCG3 well

(a)

35 403025 45 5020151050Time (yrs)



220225230235240245250255

Pres

sure

(bar

)

(b)

120125130135140145150155

Pres

sure

(bar

)


CG2 wellCG3 well

450 500150 250200 300 350 40050 1000Time (yrs)

(c)



220225230235240245250255

Pres

sure

(bar

)

450 500150 250200 300 350 40050 1000Time (yrs)

(d)







12 Geofluids


140

144

148

152

156

160Te

mpe

ratu

re (∘

C)

4510 15 20 25 30 35 405 500Time (yrs)

CG2 wellCG1A well

(a)

4510 15 20 25 30 35 405 500Time (yrs)

CG14C wellCG14 well

708090

100110120130140

Tem

pera

ture

(∘C)


(b)


CG2 wellCG1A well

144

146

148

150

152

154

156

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)

(c)


CG14C wellCG14 well

2000 4000 6000 8000 100000Time (yrs)

708090

100110120130140

Tem

pera

ture

(∘C)

(d)


CG2 wellCG1A well

5000 10000 15000 20000 25000 300000Time (yrs)


1440

1460

1480

1500

1520

1540

1560

Tem

pera

ture

(∘C)

(e)





Geofluids 13

80∘C isosurface



XY

Z

1 km

1km

80 ∘C isosurface

(a)

(b)





6 Discussion



14 Geofluids

A

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

500

1000

Elev

atio

n (m

asl

)

50 100 150 200 2500Temperature (

∘C)



minus4000

minus3000

minus2000

minus1000

minus500

2001751501251007550250

Tem

pera

ture

(∘C)


3000m asl

(a)

(b)

(d)

(e)(c)




Geofluids 15









7 Conclusions


16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















4 Geofluids


400

1000

2000

m plusmn 0

SSE

400

0

1000

2000

1

2

3

4

5

6

Volcanic complex


Ligurian complex

Scaglia complex



minus5000

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

(m)


0 1 2(km)




Geofluids 5


minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)

50 100 150 200 2500Temperature (∘C)









2flux was recorded



6 Geofluids



Volcanic complex



Scaglia complex in

Reservoir area


225 km

75km

25 km

5 km

13 kmXY

Z

Fault










Geofluids 7

Topographic surface

Reservoir area




03∘C10m

- 1 bar10m











8 Geofluids












Geofluids 9

RAI01 Alfina002

Alfina015


XY

Z

(a) 0 years

RAI01 Alfina002

Alfina015

Temperature (degC)

XY

Z 15 50 100 150 200 263

(b) 20000 years

RAI01 Alfina002

Alfina015

XY

Z


(c) 125000 years




10 Geofluids

50 100 150 2000Temperature (∘C)

50 100 150 2000Temperature (∘C)

50 100 150 200 2500Temperature (∘C)




minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)









Geofluids 11

35 403025 45 5020151050Time (yrs)

120125130135140145150155

Pres

sure

(bar


CG2 wellCG3 well

(a)

35 403025 45 5020151050Time (yrs)



220225230235240245250255

Pres

sure

(bar

)

(b)

120125130135140145150155

Pres

sure

(bar

)


CG2 wellCG3 well

450 500150 250200 300 350 40050 1000Time (yrs)

(c)



220225230235240245250255

Pres

sure

(bar

)

450 500150 250200 300 350 40050 1000Time (yrs)

(d)







12 Geofluids


140

144

148

152

156

160Te

mpe

ratu

re (∘

C)

4510 15 20 25 30 35 405 500Time (yrs)

CG2 wellCG1A well

(a)

4510 15 20 25 30 35 405 500Time (yrs)

CG14C wellCG14 well

708090

100110120130140

Tem

pera

ture

(∘C)


(b)


CG2 wellCG1A well

144

146

148

150

152

154

156

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)

(c)


CG14C wellCG14 well

2000 4000 6000 8000 100000Time (yrs)

708090

100110120130140

Tem

pera

ture

(∘C)

(d)


CG2 wellCG1A well

5000 10000 15000 20000 25000 300000Time (yrs)


1440

1460

1480

1500

1520

1540

1560

Tem

pera

ture

(∘C)

(e)





Geofluids 13

80∘C isosurface



XY

Z

1 km

1km

80 ∘C isosurface

(a)

(b)





6 Discussion



14 Geofluids

A

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

500

1000

Elev

atio

n (m

asl

)

50 100 150 200 2500Temperature (

∘C)



minus4000

minus3000

minus2000

minus1000

minus500

2001751501251007550250

Tem

pera

ture

(∘C)


3000m asl

(a)

(b)

(d)

(e)(c)




Geofluids 15









7 Conclusions


16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















Geofluids 5


minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)

50 100 150 200 2500Temperature (∘C)









2flux was recorded



6 Geofluids



Volcanic complex



Scaglia complex in

Reservoir area


225 km

75km

25 km

5 km

13 kmXY

Z

Fault










Geofluids 7

Topographic surface

Reservoir area




03∘C10m

- 1 bar10m











8 Geofluids












Geofluids 9

RAI01 Alfina002

Alfina015


XY

Z

(a) 0 years

RAI01 Alfina002

Alfina015

Temperature (degC)

XY

Z 15 50 100 150 200 263

(b) 20000 years

RAI01 Alfina002

Alfina015

XY

Z


(c) 125000 years




10 Geofluids

50 100 150 2000Temperature (∘C)

50 100 150 2000Temperature (∘C)

50 100 150 200 2500Temperature (∘C)




minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)









Geofluids 11

35 403025 45 5020151050Time (yrs)

120125130135140145150155

Pres

sure

(bar


CG2 wellCG3 well

(a)

35 403025 45 5020151050Time (yrs)



220225230235240245250255

Pres

sure

(bar

)

(b)

120125130135140145150155

Pres

sure

(bar

)


CG2 wellCG3 well

450 500150 250200 300 350 40050 1000Time (yrs)

(c)



220225230235240245250255

Pres

sure

(bar

)

450 500150 250200 300 350 40050 1000Time (yrs)

(d)







12 Geofluids


140

144

148

152

156

160Te

mpe

ratu

re (∘

C)

4510 15 20 25 30 35 405 500Time (yrs)

CG2 wellCG1A well

(a)

4510 15 20 25 30 35 405 500Time (yrs)

CG14C wellCG14 well

708090

100110120130140

Tem

pera

ture

(∘C)


(b)


CG2 wellCG1A well

144

146

148

150

152

154

156

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)

(c)


CG14C wellCG14 well

2000 4000 6000 8000 100000Time (yrs)

708090

100110120130140

Tem

pera

ture

(∘C)

(d)


CG2 wellCG1A well

5000 10000 15000 20000 25000 300000Time (yrs)


1440

1460

1480

1500

1520

1540

1560

Tem

pera

ture

(∘C)

(e)





Geofluids 13

80∘C isosurface



XY

Z

1 km

1km

80 ∘C isosurface

(a)

(b)





6 Discussion



14 Geofluids

A

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

500

1000

Elev

atio

n (m

asl

)

50 100 150 200 2500Temperature (

∘C)



minus4000

minus3000

minus2000

minus1000

minus500

2001751501251007550250

Tem

pera

ture

(∘C)


3000m asl

(a)

(b)

(d)

(e)(c)




Geofluids 15









7 Conclusions


16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















6 Geofluids



Volcanic complex



Scaglia complex in

Reservoir area


225 km

75km

25 km

5 km

13 kmXY

Z

Fault










Geofluids 7

Topographic surface

Reservoir area




03∘C10m

- 1 bar10m











8 Geofluids












Geofluids 9

RAI01 Alfina002

Alfina015


XY

Z

(a) 0 years

RAI01 Alfina002

Alfina015

Temperature (degC)

XY

Z 15 50 100 150 200 263

(b) 20000 years

RAI01 Alfina002

Alfina015

XY

Z


(c) 125000 years




10 Geofluids

50 100 150 2000Temperature (∘C)

50 100 150 2000Temperature (∘C)

50 100 150 200 2500Temperature (∘C)




minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)









Geofluids 11

35 403025 45 5020151050Time (yrs)

120125130135140145150155

Pres

sure

(bar


CG2 wellCG3 well

(a)

35 403025 45 5020151050Time (yrs)



220225230235240245250255

Pres

sure

(bar

)

(b)

120125130135140145150155

Pres

sure

(bar

)


CG2 wellCG3 well

450 500150 250200 300 350 40050 1000Time (yrs)

(c)



220225230235240245250255

Pres

sure

(bar

)

450 500150 250200 300 350 40050 1000Time (yrs)

(d)







12 Geofluids


140

144

148

152

156

160Te

mpe

ratu

re (∘

C)

4510 15 20 25 30 35 405 500Time (yrs)

CG2 wellCG1A well

(a)

4510 15 20 25 30 35 405 500Time (yrs)

CG14C wellCG14 well

708090

100110120130140

Tem

pera

ture

(∘C)


(b)


CG2 wellCG1A well

144

146

148

150

152

154

156

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)

(c)


CG14C wellCG14 well

2000 4000 6000 8000 100000Time (yrs)

708090

100110120130140

Tem

pera

ture

(∘C)

(d)


CG2 wellCG1A well

5000 10000 15000 20000 25000 300000Time (yrs)


1440

1460

1480

1500

1520

1540

1560

Tem

pera

ture

(∘C)

(e)





Geofluids 13

80∘C isosurface



XY

Z

1 km

1km

80 ∘C isosurface

(a)

(b)





6 Discussion



14 Geofluids

A

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

500

1000

Elev

atio

n (m

asl

)

50 100 150 200 2500Temperature (

∘C)



minus4000

minus3000

minus2000

minus1000

minus500

2001751501251007550250

Tem

pera

ture

(∘C)


3000m asl

(a)

(b)

(d)

(e)(c)




Geofluids 15









7 Conclusions


16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















Geofluids 7

Topographic surface

Reservoir area




03∘C10m

- 1 bar10m











8 Geofluids












Geofluids 9

RAI01 Alfina002

Alfina015


XY

Z

(a) 0 years

RAI01 Alfina002

Alfina015

Temperature (degC)

XY

Z 15 50 100 150 200 263

(b) 20000 years

RAI01 Alfina002

Alfina015

XY

Z


(c) 125000 years




10 Geofluids

50 100 150 2000Temperature (∘C)

50 100 150 2000Temperature (∘C)

50 100 150 200 2500Temperature (∘C)




minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)









Geofluids 11

35 403025 45 5020151050Time (yrs)

120125130135140145150155

Pres

sure

(bar


CG2 wellCG3 well

(a)

35 403025 45 5020151050Time (yrs)



220225230235240245250255

Pres

sure

(bar

)

(b)

120125130135140145150155

Pres

sure

(bar

)


CG2 wellCG3 well

450 500150 250200 300 350 40050 1000Time (yrs)

(c)



220225230235240245250255

Pres

sure

(bar

)

450 500150 250200 300 350 40050 1000Time (yrs)

(d)







12 Geofluids


140

144

148

152

156

160Te

mpe

ratu

re (∘

C)

4510 15 20 25 30 35 405 500Time (yrs)

CG2 wellCG1A well

(a)

4510 15 20 25 30 35 405 500Time (yrs)

CG14C wellCG14 well

708090

100110120130140

Tem

pera

ture

(∘C)


(b)


CG2 wellCG1A well

144

146

148

150

152

154

156

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)

(c)


CG14C wellCG14 well

2000 4000 6000 8000 100000Time (yrs)

708090

100110120130140

Tem

pera

ture

(∘C)

(d)


CG2 wellCG1A well

5000 10000 15000 20000 25000 300000Time (yrs)


1440

1460

1480

1500

1520

1540

1560

Tem

pera

ture

(∘C)

(e)





Geofluids 13

80∘C isosurface



XY

Z

1 km

1km

80 ∘C isosurface

(a)

(b)





6 Discussion



14 Geofluids

A

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

500

1000

Elev

atio

n (m

asl

)

50 100 150 200 2500Temperature (

∘C)



minus4000

minus3000

minus2000

minus1000

minus500

2001751501251007550250

Tem

pera

ture

(∘C)


3000m asl

(a)

(b)

(d)

(e)(c)




Geofluids 15









7 Conclusions


16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















8 Geofluids












Geofluids 9

RAI01 Alfina002

Alfina015


XY

Z

(a) 0 years

RAI01 Alfina002

Alfina015

Temperature (degC)

XY

Z 15 50 100 150 200 263

(b) 20000 years

RAI01 Alfina002

Alfina015

XY

Z


(c) 125000 years




10 Geofluids

50 100 150 2000Temperature (∘C)

50 100 150 2000Temperature (∘C)

50 100 150 200 2500Temperature (∘C)




minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)









Geofluids 11

35 403025 45 5020151050Time (yrs)

120125130135140145150155

Pres

sure

(bar


CG2 wellCG3 well

(a)

35 403025 45 5020151050Time (yrs)



220225230235240245250255

Pres

sure

(bar

)

(b)

120125130135140145150155

Pres

sure

(bar

)


CG2 wellCG3 well

450 500150 250200 300 350 40050 1000Time (yrs)

(c)



220225230235240245250255

Pres

sure

(bar

)

450 500150 250200 300 350 40050 1000Time (yrs)

(d)







12 Geofluids


140

144

148

152

156

160Te

mpe

ratu

re (∘

C)

4510 15 20 25 30 35 405 500Time (yrs)

CG2 wellCG1A well

(a)

4510 15 20 25 30 35 405 500Time (yrs)

CG14C wellCG14 well

708090

100110120130140

Tem

pera

ture

(∘C)


(b)


CG2 wellCG1A well

144

146

148

150

152

154

156

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)

(c)


CG14C wellCG14 well

2000 4000 6000 8000 100000Time (yrs)

708090

100110120130140

Tem

pera

ture

(∘C)

(d)


CG2 wellCG1A well

5000 10000 15000 20000 25000 300000Time (yrs)


1440

1460

1480

1500

1520

1540

1560

Tem

pera

ture

(∘C)

(e)





Geofluids 13

80∘C isosurface



XY

Z

1 km

1km

80 ∘C isosurface

(a)

(b)





6 Discussion



14 Geofluids

A

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

500

1000

Elev

atio

n (m

asl

)

50 100 150 200 2500Temperature (

∘C)



minus4000

minus3000

minus2000

minus1000

minus500

2001751501251007550250

Tem

pera

ture

(∘C)


3000m asl

(a)

(b)

(d)

(e)(c)




Geofluids 15









7 Conclusions


16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















Geofluids 9

RAI01 Alfina002

Alfina015


XY

Z

(a) 0 years

RAI01 Alfina002

Alfina015

Temperature (degC)

XY

Z 15 50 100 150 200 263

(b) 20000 years

RAI01 Alfina002

Alfina015

XY

Z


(c) 125000 years




10 Geofluids

50 100 150 2000Temperature (∘C)

50 100 150 2000Temperature (∘C)

50 100 150 200 2500Temperature (∘C)




minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)









Geofluids 11

35 403025 45 5020151050Time (yrs)

120125130135140145150155

Pres

sure

(bar


CG2 wellCG3 well

(a)

35 403025 45 5020151050Time (yrs)



220225230235240245250255

Pres

sure

(bar

)

(b)

120125130135140145150155

Pres

sure

(bar

)


CG2 wellCG3 well

450 500150 250200 300 350 40050 1000Time (yrs)

(c)



220225230235240245250255

Pres

sure

(bar

)

450 500150 250200 300 350 40050 1000Time (yrs)

(d)







12 Geofluids


140

144

148

152

156

160Te

mpe

ratu

re (∘

C)

4510 15 20 25 30 35 405 500Time (yrs)

CG2 wellCG1A well

(a)

4510 15 20 25 30 35 405 500Time (yrs)

CG14C wellCG14 well

708090

100110120130140

Tem

pera

ture

(∘C)


(b)


CG2 wellCG1A well

144

146

148

150

152

154

156

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)

(c)


CG14C wellCG14 well

2000 4000 6000 8000 100000Time (yrs)

708090

100110120130140

Tem

pera

ture

(∘C)

(d)


CG2 wellCG1A well

5000 10000 15000 20000 25000 300000Time (yrs)


1440

1460

1480

1500

1520

1540

1560

Tem

pera

ture

(∘C)

(e)





Geofluids 13

80∘C isosurface



XY

Z

1 km

1km

80 ∘C isosurface

(a)

(b)





6 Discussion



14 Geofluids

A

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

500

1000

Elev

atio

n (m

asl

)

50 100 150 200 2500Temperature (

∘C)



minus4000

minus3000

minus2000

minus1000

minus500

2001751501251007550250

Tem

pera

ture

(∘C)


3000m asl

(a)

(b)

(d)

(e)(c)




Geofluids 15









7 Conclusions


16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















10 Geofluids

50 100 150 2000Temperature (∘C)

50 100 150 2000Temperature (∘C)

50 100 150 200 2500Temperature (∘C)




minus5000

minus4000

minus3000

minus2000

minus1000

0

1000

Dep

th (m

)









Geofluids 11

35 403025 45 5020151050Time (yrs)

120125130135140145150155

Pres

sure

(bar


CG2 wellCG3 well

(a)

35 403025 45 5020151050Time (yrs)



220225230235240245250255

Pres

sure

(bar

)

(b)

120125130135140145150155

Pres

sure

(bar

)


CG2 wellCG3 well

450 500150 250200 300 350 40050 1000Time (yrs)

(c)



220225230235240245250255

Pres

sure

(bar

)

450 500150 250200 300 350 40050 1000Time (yrs)

(d)







12 Geofluids


140

144

148

152

156

160Te

mpe

ratu

re (∘

C)

4510 15 20 25 30 35 405 500Time (yrs)

CG2 wellCG1A well

(a)

4510 15 20 25 30 35 405 500Time (yrs)

CG14C wellCG14 well

708090

100110120130140

Tem

pera

ture

(∘C)


(b)


CG2 wellCG1A well

144

146

148

150

152

154

156

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)

(c)


CG14C wellCG14 well

2000 4000 6000 8000 100000Time (yrs)

708090

100110120130140

Tem

pera

ture

(∘C)

(d)


CG2 wellCG1A well

5000 10000 15000 20000 25000 300000Time (yrs)


1440

1460

1480

1500

1520

1540

1560

Tem

pera

ture

(∘C)

(e)





Geofluids 13

80∘C isosurface



XY

Z

1 km

1km

80 ∘C isosurface

(a)

(b)





6 Discussion



14 Geofluids

A

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

500

1000

Elev

atio

n (m

asl

)

50 100 150 200 2500Temperature (

∘C)



minus4000

minus3000

minus2000

minus1000

minus500

2001751501251007550250

Tem

pera

ture

(∘C)


3000m asl

(a)

(b)

(d)

(e)(c)




Geofluids 15









7 Conclusions


16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















Geofluids 11

35 403025 45 5020151050Time (yrs)

120125130135140145150155

Pres

sure

(bar


CG2 wellCG3 well

(a)

35 403025 45 5020151050Time (yrs)



220225230235240245250255

Pres

sure

(bar

)

(b)

120125130135140145150155

Pres

sure

(bar

)


CG2 wellCG3 well

450 500150 250200 300 350 40050 1000Time (yrs)

(c)



220225230235240245250255

Pres

sure

(bar

)

450 500150 250200 300 350 40050 1000Time (yrs)

(d)







12 Geofluids


140

144

148

152

156

160Te

mpe

ratu

re (∘

C)

4510 15 20 25 30 35 405 500Time (yrs)

CG2 wellCG1A well

(a)

4510 15 20 25 30 35 405 500Time (yrs)

CG14C wellCG14 well

708090

100110120130140

Tem

pera

ture

(∘C)


(b)


CG2 wellCG1A well

144

146

148

150

152

154

156

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)

(c)


CG14C wellCG14 well

2000 4000 6000 8000 100000Time (yrs)

708090

100110120130140

Tem

pera

ture

(∘C)

(d)


CG2 wellCG1A well

5000 10000 15000 20000 25000 300000Time (yrs)


1440

1460

1480

1500

1520

1540

1560

Tem

pera

ture

(∘C)

(e)





Geofluids 13

80∘C isosurface



XY

Z

1 km

1km

80 ∘C isosurface

(a)

(b)





6 Discussion



14 Geofluids

A

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

500

1000

Elev

atio

n (m

asl

)

50 100 150 200 2500Temperature (

∘C)



minus4000

minus3000

minus2000

minus1000

minus500

2001751501251007550250

Tem

pera

ture

(∘C)


3000m asl

(a)

(b)

(d)

(e)(c)




Geofluids 15









7 Conclusions


16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















12 Geofluids


140

144

148

152

156

160Te

mpe

ratu

re (∘

C)

4510 15 20 25 30 35 405 500Time (yrs)

CG2 wellCG1A well

(a)

4510 15 20 25 30 35 405 500Time (yrs)

CG14C wellCG14 well

708090

100110120130140

Tem

pera

ture

(∘C)


(b)


CG2 wellCG1A well

144

146

148

150

152

154

156

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)

(c)


CG14C wellCG14 well

2000 4000 6000 8000 100000Time (yrs)

708090

100110120130140

Tem

pera

ture

(∘C)

(d)


CG2 wellCG1A well

5000 10000 15000 20000 25000 300000Time (yrs)


1440

1460

1480

1500

1520

1540

1560

Tem

pera

ture

(∘C)

(e)





Geofluids 13

80∘C isosurface



XY

Z

1 km

1km

80 ∘C isosurface

(a)

(b)





6 Discussion



14 Geofluids

A

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

500

1000

Elev

atio

n (m

asl

)

50 100 150 200 2500Temperature (

∘C)



minus4000

minus3000

minus2000

minus1000

minus500

2001751501251007550250

Tem

pera

ture

(∘C)


3000m asl

(a)

(b)

(d)

(e)(c)




Geofluids 15









7 Conclusions


16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















Geofluids 13

80∘C isosurface



XY

Z

1 km

1km

80 ∘C isosurface

(a)

(b)





6 Discussion



14 Geofluids

A

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

500

1000

Elev

atio

n (m

asl

)

50 100 150 200 2500Temperature (

∘C)



minus4000

minus3000

minus2000

minus1000

minus500

2001751501251007550250

Tem

pera

ture

(∘C)


3000m asl

(a)

(b)

(d)

(e)(c)




Geofluids 15









7 Conclusions


16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















14 Geofluids

A

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

A

300

minus1000

minus2000

minus3000

minus4000

minus500

0 aslSealing units

Inte

rplu

me

Axia

l

Inte

rsec

ting

Out

side

7500 15000

Reservoir


XY

Z

Alfin

a015

A

minus4500

minus4000

minus3500

minus3000

minus2500

minus2000

minus1500

minus1000

minus500

0

500

1000

Elev

atio

n (m

asl

)

50 100 150 200 2500Temperature (

∘C)



minus4000

minus3000

minus2000

minus1000

minus500

2001751501251007550250

Tem

pera

ture

(∘C)


3000m asl

(a)

(b)

(d)

(e)(c)




Geofluids 15









7 Conclusions


16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















Geofluids 15









7 Conclusions


16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















16 Geofluids

35 403025 45 5020151050Time (yrs)


125

130

135

140

145

150

155Pr

essu

re (b

ar)


(a)

35 403025 45 5020151050Time (yrs)


210215220225230235240245250

Pres

sure

(bar

)


(b)


450 500150 250200 300 350 40050 1000Time (yrs)

125

130

135

140

145

150

155

Pres

sure

(bar

)


(c)


450 500150 250200 300 350 40050 1000Time (yrs)

210215220225230235240245250

Pres

sure

(bar

)


(d)


147

148

149

150

151

152

153

Tem

pera

ture

(∘C)

40 45 5020 25 30 35105 150Time (yrs)


(e)


708090

100110120130140150

Tem

pera

ture

(∘C)

5 10 15 20 25 30 35 40 45 500Time (yrs)



146148150152154156158160162

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(g)


708090

100110120130140150

Tem

pera

ture

(∘C)

2000 4000 6000 8000 100000Time (yrs)


(h)


Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















Geofluids 17





Disclosure




Acknowledgments


References


















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















18 Geofluids


































Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















Geofluids 19






























Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy
















Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















Modeling Highly Buoyant Flows in the Castel Giorgio: Torre...

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Transcript of Modeling Highly Buoyant Flows in the Castel Giorgio: Torre...