| Abstract |
There are >400 abandoned petroleum wells in onshore New Zealand that can potentially be harnessed for geothermal energy for direct heat applications, geothermal power production and cogeneration and development as pseudo hot spring systems for use in tourism and health spas. Well depths range from 17 to 5065m. Bottom hole temperatures (BHT) vary from 17oC to 175oC. The minimum estimated accessible heat from these wells at BHT>20oC is 8.6 PJ/a, with recoverable heat energy of 0.86 PJ/a. About 0.3 PJ/a of this is recoverable from wells with BHT>95oC, suitable for power production using a binary cycle or hybrid system. Taranaki, the only producing oil, gas and condensate region in the country, accounts for 40% of all abandoned petroleum wells and 76% of potential heat energy. Taranaki has large energy-intensive dairy, horticultural and food-producing/processing industries that could benefit from geothermal energy production using abandoned infrastructures, as the hydrocarbon reservoirs decline. Although the temperatures and fluid flow rates of abandoned wells in Taranaki and other regions may be geothermally viable, there are still many geoscientific, technical and non-technical problems to overcome before the first well can be converted for geothermal use and a pilot plant set up. |