Geothermics 33 (2004) 401–419 Computer modelling of the Wairakei–Tauhara geothermal system, New Zealand Warren Mannington, Michael O’Sullivan ∗ , David Bullivant Department of Engineering Science, University of Auckland, Private Bag 92019, Auckland, New Zealand Received 6 August 2003; accepted 8 September 2003 Available online 28 February 2004 Abstract The Wairakei–Tauhara geothermal system has been of interest as a modelling test case for a number of years. In particular it has been the subject of modelling studies at the University of Auckland since the early 1980s. The model presented here is the latest in a succession of these models. During the last 5 years the model has been significantly updated. Grid refinement, manual calibration and automated calibration, using the iTOUGH2 code, have been used to improve the model, which now agrees well with most of the available field data. © 2004 CNR. Published by Elsevier Ltd. All rights reserved. Keywords: Geothermal; Modelling; Simulation; Wairakei; Tauhara; TOUGH2; New Zealand 1. Introduction The Computer Modelling Group of the Department of Engineering Science has developed a succession of models of the Wairakei–Tauhara geothermal system. Brief summaries of these studies have been presented at conferences (see O’Sullivan et al., 1998; Mannington et al., 2000a) with more comprehensive details in reports prepared for consent processes (i.e. Mannington et al., 2000b, 2001). The field operator, Contact Energy Limited (Contact), is using the model in support of their Wairakei Geothermal Field 2001 resource consent application and in support of field management. The purpose of this paper is to present details of the current model, particularly the improvements that have been made over the last 5 years, which have resulted in a model that now agrees well with most of the available field data. ∗ Corresponding author. Tel.: +64-9-373-7599x88393; fax: +64-9-373-7468. E-mail address: m.osullivan@auckland.ac.nz (M. O’Sullivan). 0375-6505/$30.00 © 2004 CNR. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.geothermics.2003.09.009