The 2010 Akutan Exploratory Drilling Program: Preliminary Findings

Abstract

In 2010, a geothermal exploratory drilling program was conducted on Akutan Island, Alaska. The purpose of the drilling program was to obtain temperature gradient data to constrain resource capacity. The wells were designed to allow long-term monitoring and possible testing of the Akutan geothermal field. The 2010 drilling operations were carried out using wireline core equipment and were supported by helicopter. Two wells were drilled to respective depths of 253.9 meters and 457.2 meters. The first well (TG-2) was drilled directly above an outflow aquifer(s). A preliminary analysis of the TG-2 well showed that the well made 2-phase flow with a 190 liter per minute liquid phase via a 96 mm hole and from a depth of 177 to 178 m. The second well (TG-4) was drilled at the margins of the modeled outflow in order to conceptualize the size of the outflow resource. That well had very low permeability but displayed a high temperature gradient, with an extrapolated temperature of 164 deg C at 457 m. Some evidence that a deeper, hotter resource exists at or near the TG-4 site was found using mineralogical data. Preliminary analysis of data suggests that a pumped production well at the TG-2 site would be capable of a maximum production of 2.3 MW. Geochemical sampling of the fumarole gasses was carried out on the flank of the Akutan Volcano concurrent with the drilling. The data obtained from drilling will be combined with core and geochemical analysis in order to form a resource model of the field preliminary to production drilling.