The Geochemistry of the Deep Reservoir Wells in Kizildere Geothermal Field (Turkey)

Abstract

Kizildere Geothermal Field is the first discovered high enthalpy geothermal field that is used for electricity production in Turkey. Between 1968-2008 years, 25 wells geothermal wells were drilled by the government support at the field. At the end of 2008, after the privatization of Kizildere Geothermal Field, Zorlu Energy Group has drilled 19 new production and reinjection wells with the scope of 80 MWe new geothermal power plant investment between 2009-2012. The depths of these new wells change between 1551-2872 meters and mostly deeper than the previous wells in the field. Reservoir temperatures of the new production wells change between 220-245°C. The new 80 MWe power plant was put in to use at the last quarter of 2013 and total installed capacity of the field has reached to 95 MWe with the old power plant. The new production wells represent the deep reservoir and the electrical conductivity (EC) values at liquid phase change between 4600-5200 ìS/cm at the west of the field while these values change between 3450-4110 ìS/cm in the new reinjection wells at the east of the field. Silica values conform to reservoir temperatures and change between 497-687 mg/l in the deep reservoir, and between 228-402 mg/l in reinjection wells. ä18O values of water phase change between -4,30 %o and -6,1%o and ä D values change between -54%o and -59%o for production wells, while ä18O values change between -8,05%o and -10,57%o , and ä D between -59%o and -62%o for reinjection wells. In the new production wells, the dominant noncondensible gas is 98-99% CO2 that show similarity with shallow wells while new wells have slightly higher proportion H2S then shallow wells in the field.