Recent Geothermal Well Work-Over Experiences at the Kawerau Geothermal Field, New Zealand

Abstract

Ngati Tūwharetoa Geothermal Assets Ltd. (NTGA) ensures uninterrupted supply of geothermal energy to the Kawerau Industrial Complex in New Zealand through effective operations and maintenance of its steamfield assets. This paper describes the challenges encountered and the solutions developed from two recent well work-overs carried out by NTGA. The first well work-over had access issues requiring wellhead changes and the use of a smaller drilling rig to fit the small well pad. The second well work-over was required to improve wellbore access for well integrity and reservoir monitoring. The challenges identified in both work-overs required creative solutions in collaboration with the geothermal and the wider energy industry. The successful work-overs ensured the long-term reliability of the two production wells. The solutions developed and their potential applications in future work-overs are discussed.