Fluid Chemistry of Geothermal Exploration Wells at NW-Sabalan Geothermal Field, Iran

Abstract

Sabalan geothermal field has substantial geothermal potential which reasonable prospects for electric power generation and direct use. Exploration studies in the Sabalan geothermal field started in 1978 by SUNA (Renewable Energy organization of Iran). 11 wells were drilled in period of 2002 to 2011. In this report, chemical analyses of thermal fluids from wells were reviewed. The results show that wells produce predominantly from single –phase reservoir (liquid) with temperature from 225oC to 240oC. The chemical composition of reservoir water was analyzed by standard methods and subsequently classified using Cl-SO4-HCO3 and Cl-Li-B triangular diagrams. Na-K-Mg triangular diagram was used to classify waters according to the state of equilibrium at given temperatures. The geothermal waters are sodium-chloride type and from relatively old hydrothermal system. Thermal fluid is in equilibrium with reservoir rocks.