Halvor Møll Nilsen
Halvor Møll Nilsen
Publikasjoner og ansvarsområder
High-Resolution Compositional Reservoir Simulation with Dynamic Coarsening and Local Timestepping for Unstructured Grids
Numerical smearing is oftentimes a challenge in reservoir simulation, particularly for complex tertiary recovery strategies. We present a new high-resolution method that uses dynamic coarsening of a fine underlying grid in combination with local timestepping to provide resolution in time and space...
Toward accurate reservoir simulations on unstructured grids: design of simple error estimators and critical benchmarking of consistent discretization methods for practical implementation
In this paper, we aim to identify discretization errors caused by non-K-orthogonal grids upfront through simple preprocessing tools and perform a comparative study of a set of representative, state-of-the-art, consistent discretizations [multipoint flux approximation (MPFA-O), mimetic finite...
Nonlinear Domain Decomposition Preconditioning for Field-Scale Subsurface Flow Simulation
Efficient Adjoint-Based Well-Placement Optimization Using Flow Diagnostics Proxies
Optimizing placement and trajectory of wells is a computationally demanding, and hence time-consuming task due to the high number of simulations typically required to achieve a local optimum. In this work, we combine three remedies for speeding up the workflow; firstly, we employ a flow-diagnostics...
Comparison between algebraic multigrid and multilevel multiscale methods for reservoir simulation
Multiscale methods for solving strongly heterogenous systems in reservoirs have a long history from the early ideas used on incompressible flow to the newly released version in commercial simulation. Much effort has been put into making the MsFV method work for fully unstructured multiphase problems...
Multi-model hybrid compositional simulator with application to segregated flow
How to use recent developments of the MATLAB Reservoir Simulation Toolbox for fast prototyping of complex fluid models
Evaluating thermal losses and storage capacity in high-temperature aquifer thermal energy storage (HT-ATES) systems with well operating limits: insights from a study-case in the Greater Geneva Basin, Switzerland
An implicit local time-stepping method based on cell reordering for multiphase flow in porous media
We discuss how to introduce local time-step refinements in a sequential implicit method for multiphase flow in porous media. Our approach relies heavily on causality-based optimal ordering, which implies that cells can be ordered according to total fluxes after the pressure field has been computed...