GNS Science Consultancy Report 2006/0XX

The 16 high temperature wells selected for possible geothermal power generation (Figure
15) have estimated bottom hole temperatures 120 o C to 172 o C, drilled to >3100m and are
mostly artesian. However four of these (with yellow crosses) were drilled prior to 1980 and
the state of the casing, liners and grouting jobs is uncertain and need to be examined. All 16
wells have been plugged with cement upon abandonment.
For a binary cycle pilot plant with a capacity of about 200 kW five wells were selected based
on their bottomhole temperatures, proximity to a population centre or an industrial complex
such as Fonterra and proximity to another abandoned well that can be possibly used as a
reinjection well. These wells include Tipoka-1, Te Kiri-1, Toko-1, New Plymouth-2 or
Inglewood-1 (Table 4), listed according to priority, and shown in Figure 16. A downhole pump
may be needed in some wells to increase or sustain fluid flow. Electricity generated from
Tipoka-1 or Te Kiri-1 can be used by nearby dairy farms or Fonterra while other wells such
as from Toko-1, New Plymouth-2 and Inglewood-1 may supplement electricity from the grid
for Stratford, New Plymouth and Inglewood, respectively. Other wells with bottomhole
temperatures >120 o C near Stratford are Wharehuia-1, Piakau-1 and Waihapa-1. Another
well that could be harnessed in Inglewood is Tauteka-1. Cardiff-1, a well with a bottomhole
temperature of 153 o C may be reactivated as a source of hydrocarbons and hence not
included in the list.
More geoscientific studies need to be done on these wells before any power harnessing
could be done. The effect of drawing out large volumes of hot water on nearby activelyproducing
hydrocarbon wells is not known.
A
B
Figure 15. Distribution of abandoned onshore hydrocarbon wells in Taranaki showing (A) vertical depths and (B)
estimated bottomhole temperatures with roads and population centres. Haloed wells may be used for geothermal
power production.
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