Preliminary report on the location of producing layers of geothermal well HGP-A, Puna, Hawaii

Abstract

Geothermal well HGP-A is located on the active east rift zone of Kilauea Volcano on the island of Hawaii. It is presently the only producing geothermal well in the islands, and numerous tests have been performed on the well in an effort to obtain a better understanding of Hawaiian geothermal systems.

This paper considers various data gathered from these tests in an effort to determine the possible location of producing layers of HGP-A. Temperature recovery profiles, drilling mud losses, flow meter tests, and pressure profiles from HGP-A are analyzed. And since these data on HGP-A are limited, research done on other geothermal wells around the world displaying similar characteristics as HGP-A have been used to interpret some of the data but only to describe the general characteristics of a geothermal well.

All data, examined first by type and then collectively, indicate the following about the location of the producing zones of HGP-A and the permeabilities associated with these regions: - strata between 4300 - 4500 feet and 6000 feet to bottomhole appear to be major producing layers; - secondary production appears to occur between 4600 - 5900 feet, an area of alternating permeable and impermeable layers.

In other words, the region about 4500 feet seems to mark the upper boundary of an active hydrothermal convection system, and permeable zones below 4500 feet may be producing regions.