Geothermal energy production is based on production of hot water from the subsurface, and exploit the energy in the water for heating and electricity production. To increase the profitability of a geothermal site, the target rock formation should have high temperatures; commonly more than 200 degrees C. Such conditions are most readily available on locations where the temperature increases quickly with depth, for instance in volcanic areas in Iceland. It is an ongoing effort to produce from ever hotter formations. Icelandic energy companies, who are also SiGS partners, have a goal to produce from supercritical conditions, where water has above 374 degrees Celsius, and pressures above 220 bars.

Compared with other and better-known subsurface processes, such as production of oil as well as geothermal energy with lower temperature, the high temperatures considered in the SiGS project also introduce different dominant physical processes. For instance, injection of cold fluids during drilling or production may alter properties of existing fractures in the rock, or even trigger formation of new fractures. Similarly, temperature changes may disturb the existing chemical balance in the host rock. These processes will modify the flow properties of the rock, and thus both how energy is originally distributed in the rock and how the rock responds to production of the energy.

Mathematical modeling and numerical simulations are important tools to study such subsurface processes. However, in the regime of extreme temperatures, existing models cannot give satisfactory resolution. SiGS aims to develop new methods based on a combination of mathematical modeling and analysis of field data from Icelandic geothermal fields. The models will be employed to study the relative importance of dynamical processes at high temperatures both before and during drilling, as well as under production. As such the project will contributed to enhance the economic viability of geothermal energy.