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Øystein Strengehagen Klemetsdal

Research Scientist

Øystein Strengehagen Klemetsdal

Research Scientist

Øystein Strengehagen Klemetsdal
Phone: +47 984 38 639
Department: Mathematics and Cybernetics
Office: Oslo

Publications and responsibilities

Publication
https://www.sintef.no/en/publications/publication/?pubid=CRIStin+1815343

In this work, we review a set of consistent discretizations for second-order elliptic equations, and compare and contrast them with respect to accuracy, monotonicity, and factors affecting their computational cost (degrees of freedom, sparsity, and condition numbers). Our comparisons include the lin...

Year 2020
Type Part of a book/report
Publication
https://www.sintef.no/en/publications/publication/?pubid=CRIStin+1776208

We present a robust and flexible sequential solution approach in which the flow equation is solved on the original grid, whereas the transport equations are solved with a new dynamic coarsening method that adapts the grid resolution locally to reduce the number of cells as much as possible. The resu...

Year 2020
Type Journal publication
Publication
https://www.sintef.no/en/publications/publication/?pubid=CRIStin+1710251

The fully implicit method is the most commonly used approach to solve black-oil problems in reservoir simulation. The method requires repeated linearization of large nonlinear systems and produces ill-conditioned linear systems. We present a strategy to reduce computational time that relies on two k...

Publication
https://www.sintef.no/en/publications/publication/?pubid=CRIStin+1696489

High-resolution discretizations can be advantageous in compositional simulation to reduce excessive numerical diffusion that tends to mask shocks and fingering effects. In this work, we outline a fully implicit, dynamic, multilevel, high-resolution simulator for compositional problems on unstructure...

Year 2019
Type Conference lecture and academic presentation
Publication
https://www.sintef.no/en/publications/publication/?pubid=CRIStin+1695586

A number of different multiscale methods have been developed as a robust alternative to upscaling and as a means for accelerated reservoir simulation of high-resolution geomodels. In their basic setup, multiscale methods use a restriction operator to construct a reduced system of flow equations on a...

Year 2019
Type Journal publication
Publication
https://www.sintef.no/en/publications/publication/?pubid=CRIStin+1689897

Higher-order methods have only been applied to a limited extent in simulation of real petroleum assets. Possible reasons are complex grid formats (unstructured, polyhedral cells, large aspect ratios) and need for implicit time discretization. I this talk, we outline how weighted essentially non-osci...

Authors Klemetsdal Øystein Lie Knut-Andreas Møyner Olav Mykkeltvedt Trine Solberg
Year 2019
Type Conference lecture and academic presentation
Publication
https://www.sintef.no/en/publications/publication/?pubid=CRIStin+1689896

Many multiscale methods for solving elliptic/parabolic flow equations can be written in operator form using a restriction and a prolongation operator defined over a coarse partition of an underlying fine grid. The restriction operator constructs a reduced system of flow equations on the coarse parti...

Year 2019
Type Conference lecture and academic presentation