| Title | Numerical modelling of tracer tests in the Ohaaki geothermal system |
|---|---|
| Authors | M. van Driel, T. Renaud, M. Gravatt, M. OSullivan, J. OSullivan, J. Riffault, A. Croucher, F.N. van de Vosse, N.C. Ruiz |
| Year | 2023 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | Waiwera, Ohaaki, Tracer tests |
| Abstract | The Ohaaki geothermal field (OGF) is a gassy two-phase geothermal field in the volcanic and sedimentary accumulation basin at the eastern margin of the Taupo Volcanic Zone in the central North Island of New Zealand. The long history of exploration and development of Ohaaki started with the drilling of the first well in 1965. Large-scale testing of the production wells was conducted from 1965 to mid-1971, and power production commenced in 1989. Many tracer tests have been carried out at Ohaaki to better understand flow pathways between wells. The aim of the present study is to use modelling of these tracer tests to help in improving the calibration of a reservoir model. First the available information about the historical tracer tests in Ohaaki was collected and reviewed. Three of the tracer tests were selected as the first group to be used for modelling using the parallel open-source simulator Waiwera and the latest Ohaaki model developed at the University of Auckland. Good agreement is shown between the data and the model results for some wells. For other wells where agreement is not satisfactory the mismatch is used to decide on improvements that should be made to the permeability structure of the model. |