Multi-stage preconditioners for thermal-compositional-reactive flow in porous media

JOURNAL OF COMPUTATIONAL PHYSICS

卷:418

Article

Cremon, Matthias A.^1,2  Castelletto, Nicola²  White, Joshua A.² 

[1] Stanford Univ, Dept Energy Resources Engn, Stanford, CA 94305 USA

[2] Lawrence Livermore Natl Lab, Atmospher Earth & Energy Div, Livermore, CA USA

关键词: Multi-stage Preconditioning;    Thermal-Compositional Reservoir Simulation;    Porous Media;    Iterative Methods;   

DOI  :  10.1016/j.jcp.2020.109607

来源: Elsevier

【 摘 要 】

We present a family of multi-stage preconditioners for coupled thermal-compositional-reactive reservoir simulation problems. The most common preconditioner used in industrial practice, the Constrained Pressure Residual (CPR) method, was designed for isothermal models and does not offer a specific strategy for the energy equation. For thermal simulations, inadequate treatment of the temperature unknown can cause severe convergence degradation. When strong thermal diffusion is present, the energy equation exhibits significant elliptic behavior that cannot be accurately corrected by CPR's second stage. In this work, we use Schur-complement decompositions to extract a temperature subsystem and apply an Algebraic MultiGrid (AMG) approximation as an additional preconditioning stage to improve the treatment of the energy equation. We present results for several two-dimensional hot air injection problems using an extra heavy oil, including challenging reactive In-Situ Combustion (ISC) cases. We show improved performance and robustness across different thermal regimes, from advection dominated (high Peclet number) to diffusion dominated (low Peclet number). The number of linear iterations is reduced by 40-85% compared to standard CPR for both homogeneous and heterogeneous media, and the new methods exhibit almost no sensitivity to the thermal regime. (C) 2020 Published by Elsevier Inc.

【 授权许可】

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