Geothermal projects: Exploration, Drilling, Plant, Exploitation, Operation& Maintenance Ruggero Bertani Geothermal Innovation & Sustainability Enel Green Power Trieste, December 2015
The Geothermal Value Chain Integrated business model – Striving for Excellence Centennial experience (since 1904) in geothermal electricity generation and fluid use Plant Project Development/ Exploration & Plant design/ R&D Finance Drilling operation construction • Low Enthalpy • Best practice in drilling target • Well proven concept design • Fully developed internal • Acquire land rights Innovative Geothermal safety and operations identification in diverse technologies: dry • Risk evaluation Plants procedures steam , flash and binary • Geological Model and depending on country and • Developing hybrid • Provide an environment of • Optimized geo-resource technology reservoir evaluation system management (reservoir competition in equipment • Predictive methodology for • Transmission System and power plant) for procurement and • Plant improvement: Access exploration of deep geo sustainable exploitation construction acid gas components resources • Power sales contract abatement • Standardize where possible • In house maintenance and • Skills and equipment to drill negotiation repair capability • Improved efficiency vertical and deviated • Acquisition of and flexibility • Plants remotely monitored geothermal wells concessions and controlled from a • Innovative flow testing centralized location programs to forecast well performance EGP growth in traditional high temperature resources and also in binary technology 1
The Geothermal Value Chain Prefeasibility, feasibility and project development Prefeasibility Feasibility Construction Field exploitation • Country level studies to • Surface exploration: • Wells location and • Monitoring plan rank opportunities definition, planning, target definition execution, • Resource assessment & • Site geology • Data collection and interpretation evaluation referred to analisys • Wells construction new opportunities: • Data analysis and addressing • Resource forecast interpretation to • green fields define the preliminary • Logs & tests planning • Production recovery • brow fields Geothermal Model plan definition: make up wells, stimulation • fields in • Deep exploration jobs, work over exploitation planning • Mining project definition • Environmental impact studies The entire geothermal value chain covered 2
The Geothermal exploration ..a multidisciplinary approach Geology Gravity Petrophysics DC/MT 2D & 3D Petrology Reflection seismic Fluid inclusions Geothermal model Geochemistry Seismic tomography Thermometric well Well seismic and thermal model (VSP & SWD ) Well geoph. logs The joint interpretation is the key to get the most reliable geothermal model 3
New Geothermal project development The assessment process TECHNICAL ECONOMIC Geo resource potential assessment MWt Project Capex curve Assessment Data from Development Assessment Process exploration Desin Technical Opex overcosts Assumptions assessment Power Production Curve Revenues Forecast MWe 4
New Geothermal project development The assessment process 5
The Geothermal prefeasibility Geothermal projects assessment The geothermal projects assessment is a continuous improving process along the project advancement Goals, tools and methods, reliability of the assessments change with project development level Project level Increasing With Project Progressing : Low Low High • The type and amount of available experimental data Green field • The type and effectiveness of appropriate tools for the assessment (surface exploration) K R N • The reliability of the resource assessment E O LI • The accuracy and completeness of the Capex estimation W A R L Brown field B IS • The technical data necessary for the final project design E (Deep exploration) IL K D IT G Y Decreasing With Project Progressing : E • The uncertainty of the assessment Construction • The project risk High High Low The production sustainability has to be monitored and revised also during the whole Field in operation field operational life in order to 6
New Geothermal project development The assessment process Experimental Geo Geo modelling output Reservoir Reservoir Eng. TECHNICAL Economic data tools Eng. tools modelling output PROJECT ASSESSMENT Assess. STATIC DATA Geothermal system Geo Resource static characteristics Geo resource potential • Surfaces data Modelling • Size and shape assessment potential • Well masterlogs tools • Static T P conditions MWt • T & P Static logs Capex Geothermal system • Mining DYNAMIC DATA curve Project dynamic behaviour Exploitation (partial) Reservoir Develop. under exploitation Strategy Engineering Technical Desing • Well tests • T e P decline Modelling Assumptions Opex • Production • Permeability curve sustainability characteristics (partial) Power Revenues Production Forecast MWe PPA Conditions 7
The Geothermal prefeasibility Country geothermal scouting – The process OUTPUT The scouting process steps Geothermal Atlas 1) Preliminary assessment on bibliographic data Data collection and data base organization Identifying and assessing areas of potential interest Preliminary 2) Preliminary Ranking on bibliographic data Geothermal Ranking criteria definition Ranking Application of Ranking criteria to the Atlas 3) In field studies Atlas Updating Preliminary areas selection On site reconnaissance and data collections Data evaluation and assessment updating Final 4) Ranking updating Ranking Step 1 Step 2 Step 3 FINAL OUTPUT 8
The Geothermal prefeasibility Country geothermal scouting – The Atlas Identifying and Data collection and data base assessing areas organization 9 • Bibliographic data collection Locating and bounding areas on GIS base • T Geothermometric estimation • Natural manifestations inventory • Preliminary conceptual modeling • Chemical analysis and geochemical data • Areas size estimation • Geological , tectonic, volcanological, hydrogeological • Potential resource assessment (MWT) data • Environmental and logistical conditions • Geophysical surveys evaluation (accessibility, morphology, protected areas, transmission line distance, ecc.) Data base organization • GIS Data and Geo-referenced Data within GIS SYSTEM • Not Geo-ref Data within monographic sheets framework or technical report Geothermal Atlas Step 1 Step 2 Step 3 FINAL OUTPUT 9
The Geothermal prefeasibility Country geothermal scouting – The Preliminary Ranking Choice of algorithm Selection and 10 Preliminary combining weighted analysis of the Geothermal Ranking relevant topics relevant topics Inferred Temperature Defining topic values Selection of the most Inferred size of the area interesting areas for (numerical or qualitative scale) Inferred potential (MW) Defining topic weigh further investigations Geothermal System Type on site Defining topics combining Geological framework algorithm • Volcano-tectonic setting • Natural manifestations Algorithm application for (temperature & distribution) each area • Fluid chemistry • Hydrothermal alteration • Mining exploitation activity Step 1 Step 2 Step 3 FINAL OUTPUT 10
The Geothermal prefeasibility Country geothermal scouting – in field reconnaissance In field Areas selection and in Data evaluation and 11 Geothermal reconnaissance & field reconnaissance plan assessment Atlas Updating data collection definition updating Chemical analysis Preliminary reconnaissance Data elaboration • Natural manifestation census • Outcrops and hydrothermal alteration pointing Ranking Data interpretation criteria • Access roads evaluation (geo-thermometric application • Environmental constrains revised estimation) • Preliminary geological reconnaissance Assessment revision Geochemical survey Final Ranking Step 1 Step 2 Step 3 FINAL OUTPUT 11
The Geothermal feasibility Main target and phases of the exploration Ascertain the presence of a geothermal resource and assess the technical- economical feasibility of its exploitation SURFACE EXPLORATION Two phases DEEP EXPLORATION 13
Mining target delineation and characterization Index of the main methods applied by Enel Green Power Geology and hydrogeology Geochemistry Surface Exploration tools Gravity Magnetotellurics (MT) Geophysic Reflection Seismic Well testing and logging Deep Exploration tools Final goal is the reduction of the mining risk 14
Geothermal exploration Typical field implementation of the skills Geology Typical Tools Field Geology Reflecton seismic would be the most poweful survey for exploration and well targeting but: Geochemistry Volcanic • doesn ’t work well in volcanic environment MT Green Field • it is expensive (~10 times the MT ) Geology Geochemistry Sedimentary Seismic Well testing and any Brown Field logging Exploration skills for well targeting and reservoir modeling can be helpfully used at any stage of the project: green and brown fields and fields under exploitation 15
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