Hydrologic changes at Tauhara field due to exploitation of Wairakei field

Conference · Fri Jan 01 04:00:00 EST 1982

OSTI ID:7369539

Allis, R G

The major thermal areas of Tauhara field are situated around the town of Taupo, about 8 km from the Wairakei production borefield. Within Taupo, over 400 wells have been drilled to between 30 and 150 m depth, tapping the near-surface hot water of Tauhara field for domestic heating. Analysis of many measurements made since the 1950's in both domestic wells and the hot springs of Tauhara field has failed to find evidence of a widespread decline in water level or near-surface aquifer pressure. However, a significant increase in both temperature of the near-surface aquifer, and heat flow from thermal areas of Tauhara field has occurred since the mid-1960's. This has resulted in a spread of steaming ground and 3 hydrothermal eruptions on the outskirts of Taupo. A study of pressure changes in deep wells of Tauhara field suggests a decline of around 18 bars has occurred at >400 m depth, due to exploitation at Wairakei. The deep reservoir pressure of Tauhara field is now about 7 bars higher than that of Wairakei field, and significant flow towards Wairakei production borefield is probably occurring. The lack of a significant pressure drop in the surface aquifer of Tauhara field is due to the presence of low permeability lacustrine mudstone layers covering most of the field between 100 and 400 m depth. Deep drawdown of the field has caused a steam zone to form beneath the mudstone layers, and this in turn has caused the increase in steam-heating of the surface aquifer.

• Research Organization: Department of Scientific and Industrial Research, Wairakei, New Zealand
• OSTI ID: 7369539
• Report Number(s): SGP-TR-60; CONF-821214-9; ON: DE83015865
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150202 -- Geology & Hydrology of Geothermal Systems-- Non-USA-- (-1989)
150600* -- Geothermal Energy-- Environmental Aspects
AQUIFERS
DRAWDOWN
EXPLOITATION
FLUID WITHDRAWAL
GEOTHERMAL FIELDS
Geothermal Legacy
HEAT FLOW
HEATING
HYDROLOGY
PRESSURE DROP
RESERVOIR PRESSURE
SPACE HEATING
WAIRAKEI GEOTHERMAL FIELD