The natural state and response to development of Kawerau geothermal field, New Zealand

Conference · Wed Dec 31 04:00:00 EST 1997

OSTI ID:602616

Allis, R G ^[1]

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1. Institute of Geological and Nuclear Sciences Ltd., Lower Hutt (New Zealand)

Kawerau field has been supplying steam to a pulp and paper mill for process heat and power since 1957. The highest measured temperatures, pressures and chloride concentrations occur in the south of the field towards the volcanic cone of Putauaki, consistent with deep upflow from this location. Although the field has a low resistivity anomaly of 19-35 km{sup 2} in area at about 500 m depth, most surface thermal activity and the present production borefield are located in less than half this area. Negligible long-term pressure changes have occurred at production depths due to a net mass withdrawal of around 1,000 t/h over the last 10 years. A total pressure decline of around 3 in (0.3 bar) is estimated from changes in elevation of flowing hot springs. This appears to have caused a 10 km{sup 2} subsidence anomaly of between 10 and 30 mm/y which is centred on the northern boundary of the field. Some of the early shallow production wells suffered rapid invasion by cool waters, but present production from around 1 km depth is relatively stable, exhibiting some gradual cooling and dilution trends. Apart from some silica precipitation in one well, few problems have been encountered during the 5 years of reinjection into a shallow aquifer overlying the production reservoir.

• OSTI ID: 602616
• Report Number(s): CONF-971048--
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
58 GEOSCIENCES
GEOTHERMAL ENERGY
GEOTHERMAL PROCESS HEAT
GEOTHERMAL RESOURCES
KAWERAU GEOTHERMAL FIELD
NEW ZEALAND
PAPER INDUSTRY
PRODUCTION
RESOURCE DEVELOPMENT