An Analysis of Well Measurements from the Sabalan Geothermal Area, NW Iran

Abstract

Three deep exploration wells have been drilled in the Sabalan geothermal area since 2002. The first well, NWS-1, was vertically drilled down to 3197 m depth. After drilling completion, NWS-1 was tested for its pressure response to step injection. Data was analyzed by using semi-log analysis. Result shows that the permeability thickness is about 7 d-m. Temperature and pressure profiles of the well obtained during injection test, heat up and discharge period were evaluated in order to determine locations of possible aquifers in the well. Two main and two minor feedzones recognized in the well. NWS-1 has been successfully discharged as a commercial well with power potential of about 2 MWe and the third well, NWS-4, was also able to sustain a commercial output of about 4 MWe. These results therefore represent the first successful exploration drilling programme of an intraplate trachyandesite volcano.