Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering Prof. Dr. Gioia Falcone Institute of Petroleum Engineering Dept. of Geothermal Engineering & Integrated Energy Systems
Geneva, 25th April 2013
Outline • Geothermal within the energy arena • Fundamentals of geothermal energy • Types of geothermal resources • Uses of geothermal energy • Oil & gas expertise for geothermal exploitation • Conclusions
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Fuel Shares of World Total Primary Energy Supply (2010) (IEA 2012)
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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World Electricity Generation (TWh) from Non-Hydropower Renewables by 2030 Concentrating Solar Power
Photovoltaic
(ESMAP, 2012)
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Cost-Competitiveness of Renewables
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Constant Base Load Production from Geothermal vs. Other Energy Sources
(ESMAP, 2012) Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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2010 World* CO2 Emissions** by Fuel (IEA, 2012)
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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US CO2 Emissions by Primary Energy Source
(ESMAP, 2012)
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Outline • Geothermal within the energy arena • Fundamentals of geothermal energy • Types of geothermal resources • Uses of geothermal energy • Oil & gas expertise for geothermal exploitation • Conclusions
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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The Earth’s Heat -1
(Gupta & Roy, 2007 )
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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The Earth’s Heat -2 Total heat flow observed on the Earth’s surface (& T distribution within it) is due to: ● Release of heat due to the cooling of the Earth ● Heat produced by radioactivity (amount of radioactive elements present in rocks releases enough heat to account for ~60% of total heat flow for continental crust)
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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The Earth’s Heat -3 ● Earth’s cooling process is very slow ● Temperature of mantle has decreased by 300-350°C in 3 billion years, remaining at ~4000°C at its base ● 99% of Earth is hotter than 10000C ● 99% of the 1% is hotter than 1000C
(Geothermal Education Office) Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Proof of temperature at depth… Direct measurements of T in the Earth’s interior currently limited to a depth of 12.261 km in the Kola super-deep borehole SG-3 (northwest of Russia), with BHT of 180oC. Another reliable measurement of T at great depth is in the 9.101-km deep KTB borehole in Oberpfalz, Germany, with BHT of 265oC.
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Plate Boundaries & Geothermal Spots
(Geothermal Education Office )
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Plate Tectonics
(Geothermal Education Office ) Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Geothermal Systems Convection & conduction
(Dickson & Fanelli, 2004 )
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Essential Requirements for a Geothermal System to Exist (1) a large source of heat (2) a reservoir to accumulate heat (3) a barrier to hold the accumulated heat
Analogy with petroleum systems (after Gupta & Roy, 2007 ) Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Outline • Geothermal within the energy arena • Fundamentals of geothermal energy • Types of geothermal resources • Uses of geothermal energy • Oil & gas expertise for geothermal exploitation • Conclusions
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Types of Geothermal Systems
Vapour-dominated Hot water Geo-pressured Magma Hot Dry rock (HDR) & Enhanced Geothermal Systems (EGS)
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Vapour-Dominated Most exploited fields contain water at high P & T>100 oC. When this water is brought to surface, P is reduced and a mixture of saturated steam & water is generated. There are only few geothermal fields producing superheated steam with no associated fluids (dry steam fields).
(Gupta & Roy, 2007 ) Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Hot Water Differ from vapour-dominated fields in that they are characterised by liquid water being the continuous fluid phase. Typically, 60 oC 65°C. • Current experience with HPHT drilling for oil & gas can be readily transferred to the geothermal sector. • Testing labs already have mud viscometers working up to 275 MPa & 315°C. (SPE 113852) Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Drilling & Completions -4 • Setting depth of production casing must ensure downhole pump is submerged at max flow rate. • New geothermal projects need casing diameters larger than 9 5/8”. • Thermally-induced casing fatigue & cement integrity are key issues for HDR wells as expected life time is longer than for oil & gas wells. • Premium casing connections offer excellent resistance to axial loads vs. leak resistance, but their high cost impairs the economics of marginal geothermal projects.
(SPE 113852) Prof. Dr. G. Falcone Institute of Petroleum Engineering
Typical completion for a HDR producing well
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Flow in Wells: Oil & Gas vs. Geothermal Commonly, flow in geothermal wells is water-steam. 2-phase well flow models already widely used in oil & gas industry.
(SPE 113852)
2-phase flow map (Duns & Ros, 1963). Blue points are data from geothermal wells (Garg et al., 2005) Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Flow in Geothermal Wells: Issues • Wellbore simulators for fluid & heat flow already developed, yet limited ability to match field data. • Geothermal wellbore simulator must handle 2-phase, 3-component mixtures (H2O-NaCl-CO2). • With relevant salt content in the produced fluids, these become superheated steam ∆P along the well larger than for pure H2O, due to higher fluid ρ & μ and lower specific enthalpy. • 2-phase P gradients of H2O-CO2 and H2O-CO2-NaCl mixtures smaller than in 2-phase pure H2O flows.
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Fracturing Geothermal Wells • Fracturing is key in HDR / EGS projects, where good hydraulic conductivity must be created between injection & production wells. • Oil & gas fracturing techniques in HDR geothermal settings have not been fully successful. Open fractures have short-circuited or not connected to existing natural fractures. Also, induced seismicity… • Need for new developments to incorporate dynamic poroelastic & thermoelastic effects in the formations penetrated by the fractures. Chemical stimulation also applied to geothermal wells Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Conclusions • Geothermal energy, especially HDR/EGS, is a renewable resource that can help meet the world’s growing demand. • Oil & gas expertise fully complements geothermal exploitation. Many areas exist where technology transfer between these energy sectors should be enhanced.
Prof. Dr. G. Falcone Institute of Petroleum Engineering
Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering
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Geothermal Engineering: Fundamentals & Synergies with Petroleum Engineering Prof. Dr. Gioia Falcone Institute of Petroleum Engineering Dept. of Geothermal Engineering & Integrated Energy Systems
Geneva, 25th April 2013
