The Theistareykir Geothermal Field, NE Iceland: Fluid Chemistry and Production Properties

Chemical analyses on samples from six high temperature geothermal wells in the Theistareykir geothermal field in NE Iceland are reported. The aquifer temperature is estimated to be in the range 270-290 °C, although bedrock temperature exceeds 300 °C. The wells have enthalpy ranging from liquid enthalpy at the aquifer temperature up to dry vapour enthalpy, in which case excess enthalpy is primarily due to phase segregation. The liquid is relatively dilute and under-saturated with respect to amorphous silica, down to about 10 bar-a.