Geothermal Institute

Reservoir Modelling

Geothermal supermodels

In collaboration with GNS Science researchers are developing new mathematical modelling software for the New Zealand geothermal energy industry. This will be significantly more effective than existing software in promoting environmentally sustainable and efficient energy generation. The team’s aim is to develop the next generation of integrated geophysical, chemical, and flow simulation modelling tools to better understand heat and mass transfer to and between geothermal systems in order to more reliably model production effects on geothermal fields. This project is funded by New Zealand’s Ministry for Business Innovation and Enterprise. 

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Geothermal modelling tools

The Geothermal Institute’s modellers have developed software tools for geothermal well bore simulations, automated well test analysis, and tracking of geothermal tracers. The modelling group is running large complex models of geothermal fields in New Zealand and overseas. In order to support this, a range of visualisation tools has been developed to show the simulation results. PyTOUGH scripting tools have also been developed to assist with running complex models such as that of the Lihir geothermal system, where the excavation of a gold mine has to be included in the model.

Further information can be found here.

A rotated, locally refined rectangular TOUGH2 grid with fitted surface (shaded by elevation), generated using PyTOUGH

Automated model calibration

Geothermal reservoir model calibration is another area of focus. The calibration process determines suitable parameter values for quantities such as permeability and porosity throughout the reservoir. The calibration of a large model where there may be thousands of computational blocks can be very complex. The Institute’s modellers are using innovative approaches to this problem.

Ohaaki Reservoir Model
Ohaaki Reservoir model

Fluid rock interaction

Geothermal Institute modellers are investigating several aspects of fluid rock interaction. The first of these is the modelling of subsidence in geothermal fields. They are a coupling the reservoir modelling software TOUGH2 with the ABAQUS rock mechanics simulator. Available geotechnical expertise provides insight into the compressibility properties of geothermal strata for the ABAQUS modelling. Another study is looking at the effect of the injection of cold water into a hot geothermal reservoir.

Subsidence Model
Subsidence model