The Hawaiian Scientific Observation Hole Program preliminary results and status report : 1992 presentation

The Hawaii Natural Energy Institute at the University of Hawaii has drilled three Scientific Observation Holes (SOH) in the Kilauea East Rift Zone to assess the geothermal potential of the Big Island of Hawaii, and to stimulate private development of the resource. The first hole, SOH-4, was drilled to a depth of 2,000 meters and recorded a bottom hole temperature of 306.1°C. Although evidence of fossil reservoir conditions were encountered, no zones with obvious reservoir potential were found. The second hole, SOH-1, was drilled to a depth of 1,684 meters, recorded bottom hole temperatures of 206.1°C and effectively defined the northern limit of the Hawaii Geothermal Project-A - Puna Geothermal Venture (HGP-A-PGV) reservoir. The last hole, SOH-2, was drilled to a depth of 2,073 meters, recorded a bottom hole temperature of 350.5°C and can be designated as a "discovery". The SOH program was also highly successful in developing slim hole drilling techniques and establishing subsurface geological conditions