GEOTHERMAL ENERGY SERVICES

France: Head Office -131 Bd. Carnot, 78110 Le Vésinet Aix-en-Provence Office -Villa Célony 1175 Route d’Avignon, 13090 Aix-en-Provence

Mexico : Prol. Americas 1600-02, Col. Country Club, GDL 44610, MX. www.eosys.fr – contact@eosys.fr

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PRESENTATION MISSION EOSYS assists project owners, prime contractors, local authorities, governmental agencies or departments, engineering and development companies in preliminary studies, investigations and monitoring of the most favorable sites for the implementation of geothermal installations.

These various projects may include: Heat pump systems coupled to a single or an array of Borehole Heat Exchangers. Groundwater heat pump systems Heat and electricity generation of by medium or high-temperature geothermal energy

EOSYS integrates all the available data and may recommend, if needed, to carry out further investigations like:

Acquisition/analysis satellite, UAV or aerial imagery Additional field survey Geophysical survey, data processing and interpretation Borehole survey and testing 3D Geological modelling 3D Thermal-hydrogeological modelling

Finally, EOSYS recommendations concern:

Site selection and/or preliminary specifications of geothermal systems to reach the desired power.

Description and evaluation of hydrogeological properties of geothermal reservoir (depth, size, permeability, fluid properties).

Geohazard risk assessment. Definition of exploration and/or production drilling programs.

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SERVICES EOSYS offers the following services:

Geological and hydrogeological studies To locate, define and describe thermal water reservoirs, EOSYS carries out integrated geological and hydrogeological studies including:

Geological field surveys Structural analysis using remote sensing data 3D Geological modelling Multi-element geochemical mapping Numerical flow modelling Integration of hydrodynamic data in geological models

Geophysical investigations Since 2000, EOSYS carries out refraction or high resolution reflection seismic surveys using a vibro-acoustic seismic source internally developed. This seismic source is mainly used for investigations between 10m and 300m depth. Weight drop or explosive sources can also be used depending on geological context. Modelling EOSYS carries first a 3D hydrogeological model with the required precision regardless of the project size and depth. The uncertainties are clearly identified and their potential impact is analyzed at this stage. These models are then used to support groundwater flow and heat transport simulations which contribute to an accurate design of the geothermal project and to assess interference with existing or future operations. Heat exchanges with surface can also be considered. Commercial software products like EarthVision, FEFLOW, MODFLOW or others can be used depending on project and customer requirements.

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CASE STUDIES Thermal behavior of a Geothermal Heat Pump coupled with Borehole Heat Exchangers (BHE) for individual heating and cooling needs Issues For the purpose of an individual house, Four BHE’s are installed inside 150 mm diameter and 85 meters deep vertical boreholes. The BHE consist of double U-shape-pipes in which circulates a heat exchange fluid. In heating mode, the BHE extracts heat energy from the ground, transfers that heat to the working fluid inside the heat pump. Subsurface rocks consisted of 80-100 m thick limestones overlain by marls. The issues that needed further explanation were: o Are there any interactions with neighboring

heating/cooling facilities? o What is the decrease of ground average temperature in the neighborhood of BHE and

after how many years the system reaches equilibrium and the temperature stabilizes? o Will the BHE meet the thermal demand of heat pump during its entire life cycle (20

years)?

Solutions

The proposed solution was a 3D numerical simulation by finite elements. The mesh was locally refined around boreholes. The simulated physical process was transient heat transfer. Initial state includes a constant surface temperature of 11 ° C and a geothermal gradient simulated by a heat flux of 70 mW/m2. The simulation time was 20 years. Methods Details of applied methods: o Geological synthesis from existing maps and boreholes o Input of borehole and BHE properties o Simulation time - 20 years

Simplified geologic log Temperature – initial state Temperature - final state (20 years)

Model limits

Marls Limestones Conglomerates

Alluvial deposits Limestones Shales BHE

limestones

Marls and

shales

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Exploring shallow hydrothermal systems Issues

A seaside town in southern France wanted to explore a possible hydrothermal system following positive indications obtained by drillings.

Solutions To meet this objective, it was proposed the acquisition of very high resolution (VHR) seismic reflection data along a line correlated to depth using check-shot survey data. The line was 1130 m long to insure an investigation depth of about 300m.

Methods Details of applied methods:

o Geophysical investigations using very high resolution seismic reflection method o Geophysical investigations using borehole seismic data (check-shot survey)

3D view of geological map

Structural interpretation of seismic data

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Improving the knowledge of geothermal reservoir in a very difficult hydrogeological context Issues An important spa in the South of France (35 000 visitors/year) faces a decrease of water production to less than 70 m3/h. According to chemical geothermometers, the origin of thermal water is located between 1500 and 1600 m depth with an initial temperature of 65°C. The hot springs are formed in Jurassic limestone and dolomite which outcrop on the coastal edge of a nearby pond. The water reaches large factures and cracks in the limestone and rises quickly because of its higher temperature and lower density than fresh or saltwater. During its rise to the surface, this water mixes with freshwater coming from the continent, or saltwater coming from the pond which lowers its temperature between 50 and 51°C. The spa wished to extend knowledge of the thermal reservoir using the most adapted prospective techniques (HR seismic, deep drilling). Solutions The proposed solution involved the acquisition of 6 mixed (terrestrial and marine) seismic lines using high resolution seismic reflection method. The line length was 600 to 1000 m to insure a minimum investigation depth of about 300 m. Methods Details of applied methods: o Geophysical investigations using high resolution seismic reflection method. o Morphological analysis of Digital Elevation Models. o Existing borehole data input. o 3D geological modelling of limestone top using seismic and drilling data.

3D Geological modelling Interpretation of seismic data

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Increasing thermal water resources by use of seismic reflection survey Issues A spa withdraws thermal water from a deep confined aquifer. The withdrawal is conducted using two water wells with a volume of water withdrawn of about 250 to 350.000 m3/year. Water seeps down through fissured limestones surface level at 1250 meters until it reaches 1500 m depth and then rises along fault network after a course of several decades. The spa aimed to improve the knowledge of groundwater body to implement a new deep borehole. Following the recommendations of this study, the new directed drilling allowed to increase the volume of water withdrawn annually up to 513 000 m3. Solutions A reflection seismic survey was conducted by EOSYS along a single line of 3 km long with an investigative depth of about 1.5 km. Seismic data interpretations along with surface and drilling data were used to build a 3D geological model.

Methods Details of applied methods: o Geophysical investigations using

seismic reflection method. o Morphological analysis of Digital

Elevation Models o Geological interpretation and analysis

of surface based data. o 3D geological modeling using

seismic, surface and borehole data.

3D geological model

Seismic section converted to depth draped over 3D geological model

Seismic section converted to depth

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RESOURCES

IT equipment

EOSYS offices are located in Paris and in Aix-en-Provence. Both offices are equipped

with UNIX and Windows workstations and network peripherals. Specific software applications are used in the following domains:

o Seismic processing o 3D geological modelling o Geostatistics o Scientific calculations o Photogrammetry o Remote sensing o Geographical Information Systems o Flow modelling o Project management

In-house developments, based on C programming language are used for special

purposes in:

o Geological modelling o Flow modelling o Seismic processing o Image processing

Staff

Four full time engineers, specialized in geophysics, geology and modelling work at EOSYS. Almost ten experts are regularly called upon to perform special studies. During seismic surveys or drilling operations, interim personnel are recruited and the company may then count up to fifteen or more people on its payroll.

Reflection Seismic

EOSYS owns the following seismic equipment:

A vibro-acoustic source has been developed in-house since 1998. It is specially designed for very high resolution reflection seismic and shallow well velocity surveys. This source emits a sweep of 16Hz to 200Hz. It has been geologically validated for depths of between 10m and 300m. Explosive and weight drop sources can also be used.

POLYSEIS 24-bit digital acquisition system developed by the Institut Français du Pétrole (IFPEN) with 180 active channels. It can be used with very short spreads (100m) for Very High Resolution Seismic, or very long spreads (up to 20km) for deep seismics in wireline, mixed and/or radio mode.

Single geophones or strings of 9 geophones with a frequency range of 10 Hz - 350 Hz. Triaxial geophones for measuring SV and SH waves. Seismic processing software PROMAX 2D developed by Halliburton is installed on

two Silicon Graphics workstations with all necessary peripherals.

Forages

Depending on surveys, EOSYS carries out the drilling operations itself or subcontracts them to specialized companies. EOSYS also coordinates the work of logging companies and has in-house resources for seismic logging. It can also supervise drilling operations.

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METHODS

SURFACE ANALYSIS

Remote sensing

• Satellite and aerial imageries o Structural and lithologic interpretations of Landsat, SPOT, radar images.

Photogrammetry

• Geological interpretations from aerial photographs and IR thermal images.

• Algorithm development for processing and interpretation of IR thermal images.

• DEM and orthophoto calculation from aerial stereophoto pairs or SPOT scenes

• Morphological analysis of altimetric or bathymetric data

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DETAILED GEOLOGICAL MAPPING EOSYS offers to carry out geological syntheses from available data or to acquire new data including:

• Terrain surveys o GPS assisted mappings o Terrain cross-sections o Bio-sedimentological analyses o Sequential analyses o Structural analyses

• Thin section analysis (mineralogy, biology, micro-facies)

• Statistical analysis (PCA, CA, ACH)

GEOCHEMICAL MAPPING EOSYS can design and perform geochemical mapping surveys:

Design and implementation of soil geochemistry surveys using suitable grid patterns;

Pollution hazard assessment. Terrain surveys are carried out using handheld XRF analyzers:

Niton XL3 Series Analyzer : can

analyze up to 40 elements in standard mode (Ag, Al, As, Au, Ba, Bi, Ca, Cd, Cl, Co, Cr, Cs, Cu, Fe, Hg, K, Mg, Mn, Mo, Nb, Ni, P, Pb, Pd, Rb, S, Sb, Sc, Se, Si, Sn, Sr, Te, Th, Ti, U, V, W, Zn, Zr).

Niton XL2 Series Analyzer : can analyze up to 32 elements in standard mode (Ag, As, Ba, Ca, Cd, Co, Cr, Cs, Cu, Fe, Hg, K, Mn, Mo, Ni, Pb, Pd, Rb, S, Sb, Sc, Se, Sn, Sr, Te, Th, Ti, U, V, W, Zn, Zr).

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3D GEOLOGICAL MODELLING EOSYS performs the integration of surface data (satellite, topographic, geology, structure…) and subsurface data (seismic, borehole) in order to create consistent 3D geological models at project scale. Commercial software such as EarthVision or customer’s designated software products (Petrel, Gocad) are used for that purpose. These 3D models allow checking data coherence and give an accurate description of geological structures. After model validation, EOSYS can perform:

Assessment of exploration targets

Well trajectory design Geostatistical analyses

These models can also be used by other specialists who wish to perform reservoir simulation, geomechanical or geotechnical analyses. RESERVOIR ANALYSIS

3D geological modelling aimed at checking reservoir data reliability and giving an accurate description of both internal and external reservoir geometries. Deterministic or stochastically generated petrophysical fields can be introduced. The quality of reservoir characterization is assessed and improved at this stage.

These 3D models can be used

interactively to analyze production data. Geometrical reasons for water or gas breakthrough, pressure responses between wells can be identified.

Some reservoir issues can be solved directly by running simulations using the geological model itself as a reservoir model. No time is required to transfer data to a reservoir simulator and to perform upscaling. EOSYS has developed algorithms which allow to use directly EarthVision™ to run certain types of simulations.

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EOSYS is an independent geoscience engineering company founded in 1993. EOSYS works in various sectors of economic activity to assess underground resources and development opportunities and to limit human and financial risks associated with these projects. EOSYS worked on more than 70 projects in Europe, Africa and America including:

Renewable energies, groundwater development and environmental sustainability Exploration, development and investment in mining and oil & gas ventures Design of underground storage facilities and underground works Nuclear security and defense

References:

TOTAL ENGIE(GDF) PERENCO IFPEN GEOSTOCK LA ROCHE INDUSTRIES VENCOREX (CHLORALP) SOLVAY (RHODIA) LUNDIN (COPAREX) Private investors Local authorities EGIS ANTEA

To contact us: contact@eosys.fr

MEXICO Pról. Américas 1600-02,

Col. Country Club, Guadalajara 44610

Tel/Fax: + (52) 33.36.78.92.79

FRANCE Head Office

131, Bd Carnot – 78110- LE VESINET Tel: + (33) 1.42.65.66.40

Aix-en-Provence :

Villa Célony 1175, Route d’Avignon

13090 Aix-en-Provence Tel: (+33) 04.42.66.95.00

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