Ivar Stefansson is a researcher in the Porous Media Group and the Vista Center for Modeling of Coupled Subsurface Dynamic at the Department of Mathematics of the University of Bergen (UoB). He studied nanotechnology and applied and computational mathematics at UoB, with exchange visits to the University of Stuttgart and Imperial College, London. In 2021 he graduated with a PhD from UoB with the title Modelling and simulation of thermo-hydro-mechanical processes in fractured porous media. 

Ivar’s research concerns fluid and heat flow and rock deformation in fractured porous media. He develops and implements numerical methods and simulation technology and applies these methods in simulations extending our understanding of subsurface applications such as extraction of geothermal energy, groundwater flow and CO2 storage. 

Ivar is one of the core developers of the PorePy simulation toolbox for multiphysics processes in fractured porous media. He has extensive experience from several international and interdisciplinary collaborations, including with University of Stuttgart and Imperial College, London. Starting from 2026, he will lead the FRIPRO project DifFracS on simulation of deforming fractures.  

Conference report

• Jakub Wiktor Both; Marius Nevland; Ivar Stefansson et al. (2025). Fracture reactivation in geothermal reservoirs: Strategies for numerical modeling of fracture contact mechanics in thermoporoelastic media. (external link)

Academic article

• Eirik Keilegavlen; Alessio Fumagalli; Runar Lie Berge et al. (2019). Implementation of mixed-dimensional models for flow in fractured porous media. (external link)
• Ivar Stefansson; Inga Berre; Eirik Keilegavlen (2018). Finite-volume discretisations for flow in fractured porous media. (external link)
• Ivar Stefansson; Jhabriel Varela; Eirik Keilegavlen et al. (2024). Flexible and rigorous numerical modelling of multiphysics processes in fractured porous media using PorePy. (external link)
• Inga Berre; Wietse Boon; Bernd Flemisch et al. (2021). Verification benchmarks for single-phase flow in three-dimensional fractured porous media. (external link)
• Ivar Stefansson; Eirik Keilegavlen; Sæunn Halldorsdottir et al. (2021). Numerical Modelling of Convection-Driven Cooling, Deformation and Fracturing of Thermo-Poroelastic Media. (external link)
• Eirik Keilegavlen; Runar Lie Berge; Alessio Fumagalli et al. (2021). PorePy: an open-source software for simulation of multiphysics processes in fractured porous media. (external link)
• Bernd Flemisch; Inga Berre; Wietse Boon et al. (2018). Benchmarks for single-phase flow in fractured porous media. (external link)
• Ivar Stefansson; Eirik Keilegavlen; Inga Berre (2021). A fully coupled numerical model of thermo-hydro-mechanical processes and fracture contact mechanics in porous media. (external link)
• Ivar Stefansson; Eirik Keilegavlen (2023). Numerical Treatment of State-Dependent Permeability in Multiphysics Problems. (external link)
• Inga Berre; Ivar Stefansson; Eirik Keilegavlen (2020). Fault slip in hydraulic stimulation of geothermal reservoirs: Governing mechanisms and process-structure interaction. (external link)
• Eirik Keilegavlen; Laure Duboeuf; Anna Maria Dichiarante et al. (2021). Hydro-mechanical simulation and analysis of induced seismicity for a hydraulic stimulation test at the Reykjanes geothermal field, Iceland. (external link)
• Ingrid Kristine Jacobsen; Inga Berre; Jan Martin Nordbotten et al. (2025). A Finite Volume Method for Elastic Waves in Heterogeneous, Anisotropic and Fractured Media. (external link)
• Ivar Stefansson (2024). A line search algorithm for multiphysics problems with fracture deformation. (external link)

Conference lecture

• Ivar Stefansson; Inga Berre; Eirik Keilegavlen et al. (2018). Modelling of thermal shock induced fracture growth. (external link)
• Inga Berre; Runar Lie Berge; Hau Trung Dang et al. (2020). Modelling of process-structure interaction resulting from fluid injection in fractured subsurface systems. (external link)
• Eirik Keilegavlen; Alessio Fumagalli; Ivar Stefansson et al. (2018). Unified modeling and discretization of flow in fractured porous media. (external link)
• Ivar Stefansson (2024). A simple and efficient line search for nonlinear and semismooth multiphysics problems. (external link)
• Sæunn Halldorsdottir; Inga Berre; Eirik Keilegavlen et al. (2021). Thermal fracturing and natural convection: A hidden source of geothermal activity in the earth’s crust?. (external link)
• Eirik Keilegavlen; Ivar Stefansson; Inga Berre et al. (2019). Enhancing Geothermal Reservoirs – Modelling and Analysis of Hydraulic and Thermal Stimulation. (external link)
• Ivar Stefansson (2023). Elastic normal fracture deformation ​ in thermoporomechanical media. (external link)
• Runar Lie Berge; Eirik Keilegavlen; Alessio Fumagalli et al. (2018). PorePy: A Python Simulation Tool for Fractured and Deformable Porous Media​. (external link)
• Jakub Wiktor Both; Marius Nevland; Ivar Stefansson et al. (2025). Fracture reactivation in geothermal reservoirs: Strategies for numerical modeling of fracture contact mechanics in thermoporoelastic media. (external link)
• Ivar Stefansson (2023). Modeling and Simulation of Fracture Deformation in Coupled Problems. (external link)
• Inga Berre; Shin Irgens Banshoya; Ivar Stefansson et al. (2024). Simulation of THMC processes in fractured porous media. (external link)
• Eirik Keilegavlen; Alessio Fumagalli; Ivar Stefansson et al. (2019). Mixed-dimensional discrete fracture matrix models with heterogeneous discretization and non-matching grids. (external link)
• Ivar Stefansson; Eirik Keilegavlen; Jakub Wiktor Both et al. (2024). Multiphysics simulation of fractured geothermal systems using PorePy. (external link)
• Inga Berre; Haakon Langeland Ervik; Ivar Stefansson et al. (2021). Discrete Fracture-Matrix Modelling of Coupled THM Processes and Fracture Deformation. (external link)
• Ivar Stefansson; Inga Berre; Eirik Keilegavlen (2017). Handling of Fractures and Intersections in Finite Volume Methods. (external link)
• Ivar Stefansson; Antonio Rinaldi; Thomas Driesner et al. (2022). Mixed-dimensional hydromechanical modelling of an in situ hydroshearing experiment. (external link)
• Eirik Keilegavlen; Shin Irgens Banshoya; Sæunn Halldorsdottir et al. (2022). Modeling and Simulation of Thermo-Hydro-Mechanical-Chemical Processes in Fractured Rocks with Applications to Geothermal Energy. (external link)
• Eirik Keilegavlen; Alessio Fumagalli; Runar Lie Berge et al. (2017). PorePy: A Python Simulation Tool for Fractured and Deformable Porous Media. (external link)
• Inga Berre; Bernd Flemisch; Anna Scotti et al. (2017). [2] Benchmarking and comparison of numerical methods: overall considerations and a recent study of methods for flow in fractured porous media, Flow in Deformable Porous Media: Numerics and Benchmarks. (external link)
• Ingrid Kristine Jacobsen; Inga Berre; Jan Martin Nordbotten et al. (2024). An MPSA-Newmark discretization of the elastic wave equation with absorbing boundary conditions. (external link)
• Inga Berre; Ivar Stefansson (2024). Process-structure interaction in geothermal reservoirs: modeling and simulation. (external link)
• Inga Berre; Jakub Wiktor Both; Sæunn Halldorsdottir et al. (2024). Mathematical and Numerical Modelling of Process-Structure Interaction in FracturedGeothermal Systems. (external link)
• Eirik Keilegavlen; Ivar Stefansson; Inga Berre et al. (2020). A simulation model for fracture reactivation accounting for thermo-hydro-mechanical forces with applications to geothermal systems. (external link)
• Ivar Stefansson; Inga Berre; Alessio Fumagalli et al. (2019). Numerical Methods for Flow in Fractured Porous Media in a Unified Implementation. (external link)
• Eirik Keilegavlen; Alessio Fumagalli; Runar Lie Berge et al. (2017). Discretization of mixed-dimensional problems using legacy codes. (external link)

Conference poster

• Ivar Stefansson; Eirik Keilegavlen; Inga Berre (2017). Coupling Conditions for Finite Volume Methods for Fractured Porous Media. (external link)
• Ivar Stefansson; Inga Berre; Eirik Keilegavlen (2017). Finite Volume Methods for Flow and Transport in 3-Dimensional Fractured Porous Media. (external link)
• Inga Berre; Ivar Stefansson (2024). Multi-Point Finite Volume Method for Fracture Propagation in Linear Elastic Media. (external link)
• Inga Berre; Ivar Stefansson (2024). Multi-Point Finite Volume Method for Fracture Propagation in Linear Elastic Media. (external link)
• Ivar Stefansson; Inga Berre; Eirik Keilegavlen (2019). Simulation of temperature and pressure driven fracture deformation. (external link)

Popular science article

• Ivar Stefansson (2019). Geotermisk energiproduksjon. (external link)
• Ingrid Kristine Jacobsen; Marius Nevland; Ivar Stefansson (2024). Geotermisk energi. (external link)
• Ivar Stefansson (2022). Slik kan vi hente stabil, fornybar energi fra under bakken. (external link)
• Ivar Stefansson (2022). Slik kan vi hente stabil, fornybar energi fra under bakken. (external link)

Lecture

• Ivar Stefansson; Inga Berre; Eirik Keilegavlen (2017). Coupled processes in geothermal systems. (external link)
• Ivar Stefansson; Anders Nermoen; Walter H Wheeler et al. (2024). Ground source heat in Norway – on the value gained by firm, renewable, carbon neutral, local and areal effective thermal resources by the Geothermal Energy Association of Norway. (external link)
• Ivar Stefansson (2024). Some whys and hows of computational mathematics. (external link)
• Anders Nermoen; Fionn Iversen; Ivar Stefansson (2023). Network Meeting Bergen: Ground Source Heat Pump Energy System. (external link)
• Anders Nermoen; Gilles Pelfrene; Fionn Iversen et al. (2023). GeoEnergy 2023. (external link)

Academic book chapter

• Ivar Stefansson; Inga Berre; Eirik Keilegavlen (2020). Finite Volume Discretisation of Fracture Deformation in Thermo-poroelastic Media. (external link)
• Ivar Stefansson; Runar Lie Berge; Inga Berre et al. (2021). Modelling of Thermally Induced Fracture Slip caused by Fluid Injection During Geothermal Production. (external link)

See a complete overview of publications in Cristin.

• Leads the early career project (FRIPRO) Differentiable Fracture Simulation (DifFracS).
• Participant of Center for Modeling of Coupled Subsurface Dynamics | University of Bergen
• Participant of Mathematical and Numerical Modelling of Process-Structure Interaction in Fractured Geothermal Systems (MaPSI) | Porous Media Group | UiB