# Simulation of governing processes in superheated and supercritical geothermal systems: mathematical models, numerical methods and field data (SiGS)

The SiGS project goal is to extend the understanding of superheated and supercritical geothermal resources and their response to engineering operations by combining tailored mathematical and numerical modeling with field observations.

## Hovedinnhold

Duration | 2020-2024 |

Funding | NFR, Equinor |

External partners | Equinor, Icelandic Geosurvey, HS Orka, Reykjavik Energy, Landsvirkjun |

The project aims to address two questions that are highly relevant for the efficient construction and operation of geothermal sites:

- What are the governing processes for the transport of energy from the deep roots of a geothermal field – this could be magma chambers – towards shallower parts of the rock that can be accessed by wells?
- What is the effect of the introduction of cold fluids (water or drilling fluids) on the rock permeability in superheated and supercritical geothermal systems?

To answer these questions, the project will combine mathematical modeling with numerical simulation based on information from specific geothermal sites in Iceland. To achieve this, the project also needs to develop new simulation tools that can handle interacting, and often competing, physical mechanisms that underly the two target processes. Specifically, the study of energy production from superheated and supercritical conditions entails understanding a complex interaction between fluid flow, transport of energy and chemical species, and deformation of the host rock due to changes in temperature and fluid pressure. The physical takes place in the rock proper, in networks of fractures within the rock, and on the rock-fracture interface. The fractures are not static but can open and close, or even propagate. This combination of complex and coupled physics with geometric structures (the fracture network) is difficult to represent in simulation tools. To improve the simulation technology, and thereby be better equipped to answer questions 1 and 2, the SiGS project will:

- Development of mathematical models for the fully coupled thermo-chemical-hydro-mechanical processes for fractured geothermal reservoirs.
- Development of robust and simulation techniques for the models, and implementation of the models into the simulation tool PorePy, developed at the University of Bergen.

In practice, this requires a combination of mathematical modeling, numerical methods including discretization methods and solvers, implementation, and simulation.