1. Nonlinear Multigrid for Reservoir Simulation
- Author
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Allan Peter Engsig-Karup, Klaus Langgren Eskildsen, Mark Wakefield, and Max la Cour Christensen
- Subjects
Mathematical optimization ,Computer science ,Computation ,Numerical analysis ,Linear system ,MathematicsofComputing_NUMERICALANALYSIS ,Energy Engineering and Power Technology ,010103 numerical & computational mathematics ,Geotechnical Engineering and Engineering Geology ,System of linear equations ,01 natural sciences ,010101 applied mathematics ,Reservoir simulation ,symbols.namesake ,Component (UML) ,Jacobian matrix and determinant ,symbols ,Applied mathematics ,0101 mathematics ,Temporal discretization - Abstract
Motivation In the pursuit of higher resolution simulation models that use all seismic, geological, and dynamic reservoir data and to make use of modern parallel computing architectures we consider alternative numerical methods to solve the system of equations governing subsurface porous media flow. It is standard in conventional techniques to use a global linearization in a Newton-type method to solve the strongly nonlinear system of equations arising from the spatial and temporal discretization of the governing system of PDEs. Consequently, the memory requirement to store the sparse Jacobian is significant. Such very large linear systems result in the linear solver component to constitute more than 70% of the computation time in reservoir simulators. Iterative linear solvers depend on effective preconditioners, which can be hard to parallelize to the extent required by many-core simulations. In a first step, we investigate feasibility of using the locally linearizing nonlinear multigrid method Full Approximation Scheme (FAS) in serial to establish algorithmic performance.