Study of Hydrotherml Alteration, Well Measurment Data and Thermal Fluids Geothermometry to Develop a Conceptual Model of the Sabalan Geothermal Field, NW Iran

摘要

Three deep wells were drilled by National Iranian Oil company for Renewable Energies Organization of Iran, as part of the second phase of the 2008 and 2010 drilling programs for Northwest Sabalan (NWS) Project. The main objec-tive is to use thermal fluids and hydrothermal alteration minerals geothermometry to develop a conceptual model of the Sabalan Geothermal Field. On the basis of the results of the two MT surveys and the presence of hot springs, two well exploration programme (NW-1, NW-4) and three well delineation programme (NW-6D, NW-7D, NW-10D) have been undertaken. Results of magnetotelluric surveys done by EDC in 2007 show that the hottest part of the geothermal resource possibly lies to the east-southeast of Pad E. Also, this workpresents a comprehensive review of the theoretical background used in analysing well-test, temperature and pressure logging data from the Sabalan geothermal wells. The prominence of potassic feldspars indicates that the parent magma in NW Sabalan is of the trachyte-monzonite-syenite affinity which contrasts with the intermediate andesite-diorite suite typical in Philippine geothermal systems.