Course objective:

Introducing students to geothermal energy resources, mastering elements needed to asses discovered and available reserves of geothermal fluid and considering all available methods of exploration and exploitation of geothermal reservoirs. Students will learn how to best avoid environmental impact of hydrocarbon and geothermal reservoir management.

Course content:

• Introduction to geothermal engineering, course overview, student’s responsibilities and monitoring student work
• Geoenergy origins, calculation and mapping of terrestrial heat flow, temperature distribution within Earth and thermal energy source
• Overview of properties of exploration fields and exploitation of geothermal reservoirs in Croatia, geological and thermogeological properties of thermal and subthermal sources
• Categorization of geothermal reservoirs according to reservoir temperature and pressure, reserves determination, geological and thermogeological properties of geopressured reservoirs
• Thermodynamic properties of reservoir rock and fluid, brine geochemistry, calculation methods and determination of reservoir temperature using chemical analysis of the brine
• Methods of determining reservoir and brine temperature, geothermal gradient, calculations, correlations and correction of measured temperature values
• Geological, thermogeological and physical parameters in geothermal engineering, correlations used to determine reservoir properties: temperature, thermal conductivity, thermal diffusivity, volumetric heat capacity, heat flow
• Thermodynamic production analysis, sustainability and renewability of geothermal resources
• Material balance equation – calculation for geothermal reservoir
• Temperature change as a function of time during production, heat loss in well and in transport system
• Design of reinjection of geothermal brine into the reservoir, isothermal production – brine production at constant temperature, time of isothermal production
• Exploitation of geothermal brine for thermal energy, direct use of geothermal energy, case study of geothermal reservoirs Zagreb and Bizovac
• Exploitation of geothermal brine for electric power, thermodynamic and mechanical aspects of geothermal power plants, case study of geothermal reservoirs Velika Ciglena and Kutnjak-Lunjkovec
• Technoeconomical aspects of geothermal brine production
• Regulations concerning exploration and exploitation of geothermal resources, enhanced geothermal systems, utilizing abandoned oil and gas wells as geoenergy resource.

Learning outcomes at the level of the course:

• Assess potential geothermal reservoirs by analysing geological and thermogeological parameters;
• Geothermal reservoir engineering and categorization based on physical and thermodynamic data;
• Solve heat transfer equations in porous media and heat loss in a well;
• Evaluate geothermal brine reserves with technoeconomical elaboration of geoenergy potential;
• Elaborate technical procedures for administrative start-up of geothermal energy productions – reserves report and mining project;
• Analyse exploitation of geothermal reservoirs for production of heat and electricity;
• Thermodynamic interpretation of geothermal brine and steam reservoirs.