Hydrogeology and geochemistry of the Alaşehir Piyadeler geothermal field, Manisa

Alaşehir-Piyadeler geothermal field is located 90 km away from Manisa province. Water samples were collected and evaluated by considering previous studies found in the literature. According to the International Association of Hydrogeologists, hot waters are classified as sodium and bicarbonated and cold waters are classified as calcium, magnesium, sodium bicarbonated. If waters found in the field area is analyzed for direct usage, hot waters are as unsuitable but cold waters are well-suited irrigation water. Palaeozoic aged Menderes massive has fractured and porous rock which constitudes the basement of the field. Neogen aged terrestrial deposits behaves as caprock of the geothermal system because of clay compositions in it. Quaternary aged alluvials in the field area have cold waters reservoir characteristics. 18O-D isotops analysis shows that hot waters are meteoric origin which may had water rock interaction. Geothermometer methods suggesting temperature ranging 180-230 oC, silica geothermometers shows more reliable results. One of the most important problem faced in geothermal systems is scaling related production loss. In order to prevent this problem, inhibitor with a proper chemical composition is essential. While deciding on the type of inhibitor, softwares are used to estimate possible scaling compositions. In the study area, It was found that calcite and metal-ametal silicate scaling may create main problem during long term production and reinjection.