Hydrogeological investigation of Canakkale Tuzla-Gulpinar geothermal fields

Tuzla-Gülpınar geothermal area is located in northwestern side of Turkey, approximately 100 km far away from the Çanakkale Province. In this study, water samples were collected from various locations and analysis results of water samples, along with those taken from the literature, were used to determine the hydrogeochemical properties and scaling problems. The waters are all Na-Cl type and have the same origin, although some samples show variation in ionic values due to cold water infiltration. Based on the intergrated use of well data and geopyhsical studies in the region, two reservoir rocks are identified: Early Miocene volcanic rocks forming the shallow reservoir and Permian limestones forming the deep reservoir in the area. In Tuzla geothermal field, hot water rises through the Tuzla fault which forms upflow-outflow zones in the area. Silica geothermometers are found to be more reliable for the geothermal waters in the study area. Based on cation geothermometers, reservoir temperature seems to range from 164°C–220°C in areas recharged from upflow zone in Tuzla region, while from 90°C to 145 °C areas recharged from outflow zone in Gülpinar region based on silica geothermometers. The reservoir temperature of the T-2 well, one of the warmest wells of the Tuzla geothermal power plant, is 173 ° C, so this temperature supports the geothermometer results. The major problem in using geothermal energy is scaling problem. According to the geochemical evaluation carried out by the PhreeqC program, calcite and aragonite scaling are determined and these minerals can be create a major problem during production and injection phases. Keywords: Geothermal fluids, Hydrogeochemistry, Geothermometer, Scaling, Reservoir