Geothermal energy constitutes an important renewable resource in Turkey that has been extensively utilized for heating buildings, power generation, greenhouse farming and various other industries. One of the most remarkable geothermal locations in Turkey is the low-enthalpy area of Afyon, where five main low-temperature (30–110℃) geothermal fields are exploited. However, further exploration drilling sites have proven inconclusive, casting doubts on the effective presence of high-temperature geothermal systems in the region. Part of the challenge is that the geometry, size and depth of the heat source of the geothermal system is poorly constrained. | Turkish Journal of Earth Sciences Turkish J Earth Sci 2021 30 536-550 http earth TÜBİTAK Research Article doi yer-2101-21 A numerical approach to verify the reservoir temperature of the Afyon geothermal fields Turkey Özgür KARAOĞLU Department of Geological Engineering Faculty of Engineering and Architecture Eskişehir Osmangazi University Eskişehir Turkey Received Accepted Published Online Final Version Abstract Geothermal energy constitutes an important renewable resource in Turkey that has been extensively utilized for heating buildings power generation greenhouse farming and various other industries. One of the most remarkable geothermal locations in Turkey is the low-enthalpy area of Afyon where five main low-temperature 30 110 geothermal fields are exploited. However further exploration drilling sites have proven inconclusive casting doubts on the effective presence of high-temperature geothermal systems in the region. Part of the challenge is that the geometry size and depth of the heat source of the geothermal system is poorly constrained. It is documented that the Afyon region hosts voluminous and well-preserved potassic ultrapotassic volcanic successions that formed between 15 and 8 Ma. It is also well known that volcanoes are fed by magma chambers and reservoirs which can be linked to fault zones and geothermal systems. In this study the origin of the geothermal systems in Afyon is explored by considering the maximum recorded well-head temperature of 110 and the estimated reservoir temperature of 125 from hydrochemistry data. The calculated and measured temperatures are interpreted in terms of thermal finite element method thermal models illustrate the possible temperature distribution throughout the crust assuming an arrangement of a crustal magma chamber and a geothermal gradient of 30 km. Results show that the temperature of the fluids at the measured well-head temperature
