Abstract:
Modelling of the Wairakei‐Tauhara geothermal field, New Zealand, has been on going for a number of years. The reservoir model, based on the TOUGH2 simulator, has been updated and re‐calibrated with the advancement of computer hardware and modelling techniques and the availability of new field data. In the last few years the field operator, Contact Energy Limited, has become interested in the Tauhara sector of the system and has drilled several new wells. These wells have provided down‐hole temperatures and information about the geological structure at Tauhara. In previous version of the model some of the Tauhara sector was not accurately represented, but this approximation was not important because the connection across to Wairakei is weak. Now because of Contact Energy’s new priorities it has become important to better represent the Tauhara sector in the model and the new data has made it possible to carry out calibration. As well as improving the model at Tauhara other improvements have been made. For example the model has been deepened so that it includes more of the large-scale convective system and is less dependent on assumptions about deep recharge. The new model matches well most of the data available on down-hole temperatures and historical changes in production enthalpies and reservoir and monitor pressures. The model has been used to simulate six future scenarios for production and injection at both Wairakei and Tauhara.
