The geochemistry of the HGP-A geothermal well : a review and an update

Abstract

The HGP-A geothermal well, located on the lower east rift system of Kilauea volcano, has provided steam and hot water to a 3MWe wellhead generator facility on a continuous basis since December 1981. Since production began there have been substantial changes in the composition of the reservoir fluids that suggest several important conclusions regarding the HGP-A well and the reservoir associated with the Kilauea east rift zone. Among these are: that preproduction reservoir fluids have moderate to low dissolved solids concentrations; that long-term fluid production can result in encroachment of heavily modified seawater into the geothermal system; and that deposition of secondary minerals from the intruding seawater may result in the obstruction and eventual sealing of the saline aquifers