Andreas Thune defended his PhD thesis

On Tuesday 19 September 2023 at 13:15, Andreas Thune defended his PhD thesis "High performance computing for reservoir simulation".

The defence was held in the Hans Petter Langtangen (HPL) Lecture Hall at Simula.

Main research findings

Reservoir simulation is an important tool in the oil and gas industry, using mathematical models to predict the flow of fluids in sub-surface petroleum reservoirs. Oil and gas companies use reservoir simulations to make economic decisions and to develop and manage the production of new fields. The demand for accuracy and the typical size of reservoirs introduces the need for a lot of computing power. To efficiently utilize computer resources, the simulations must be divided into multiple small tasks that can be run in parallel. Reservoir simulation-specific aspects, such as complex geology and well modeling, complicate the parallelization of reservoir simulations. In this thesis, we considered domain decomposition strategies for parallel reservoir simulations and their impact on performance. A new graph partitioning technique that incorporates reservoir heterogeneity while maintaining low parallel overhead is presented. We studied efficient parallelization of linear solvers for reservoir simulation and the impact of the preconditioning strategy on the overall performance. Understanding the underlying hardware architecture of modern computers helps achieve resource efficient simulations. We introduce a new modeling methodology for estimating parallel overhead on computing platforms with heterogeneous inter-process interconnects. The research of the thesis contributed to the development of an open-source reservoir simulator.

Prior to the defence, at 11:15 on the same day, Andreas presented his trial lecture, “Is there a good compromise between energy consumption and efficiency of HPC applications?”

Adjudication committee:

  • Professor Bernd Flemisch, Department of Hydromechanics and Modelling of Hydrosystems, University of Stuttgart, Germany
  • Research Scientist Emmanuelle Saillard, Inria Bordeaux, France
  • Professor Özgu Alay, Department of Informatics, University of Oslo, Norway


  • Professor Xing Cai, Simula Research Laboratory & Department of Informatics, University of Oslo
  • Specialist in reservoir technology Alf Birger Rustad, Equinor
  • Professor Tor Skeie, Department of Informatics, University of Oslo & Simula Research Laboratory
  • Associate Professor Ernst Gunnar Gran, Department of Information Security and Communication Technology, Norwegian University of Science and Technology

Read more at the UiO Department of Informatics web page.

Related employees