Practical Applications





  • Subsurface Flow Simulation


  • What is subsurface flow simulation?

Subsurface flow, in hydrology, is the flow of water beneath the earth’s surface that constitutes part of the water cycle.


uw1            uw2

  • Numerical Results for Subsurface Flow Simulation


uw-table

Reference:  Cheng, Huang, Shu, X. Zhang, Zhang, and Zhou (2012)



  • Reservoir Simulation

  
  • What is Reservoir Simulation?

Reservoir simulation is the art of combining physics, mathematics, reservoir engineering, and computer programming to develop a tool for predicting hydrocarbon reservoir performance via various operating strategies. It is an important decision-making tool. For example, engineers use it to obtain information pertaining to the processes that take place in oil reservoirs. Such information enables an analysis of the various recovery strategies in order to effect optimal oil recovery. The crucial part of reservoir simulations is to solve large-scale discretized PDEs (highly coupled, nonsymmetric, and indefinite) over and over again. However, this is also the most time-consuming process of any modern petroleum reservoir simulator (more than 75%). The complexity of the geometry and of the physical model, heterogeneity, and size of reservoir model are continuing to grow, which makes these linear systems more difficult to solve using standard direct or iterative solvers.


PRS-1         
 
A typical reservoir.

  • The FASP Method for Reservoir Simulations

The FASP method takes full advantage of the underlying physical and analytic properties of the mathematical model.

        That is
  • Transforms the complicated Jacobian system into three simpler auxiliary problems: an elliptic problem for the pressure variables, a hyperbolic problem for the saturation variables, and a purely algebraic problem for the well bottom-hole pressure variables.
  • Thus, it can be used to design efficient and robust smoothers or preconditioners for each auxiliary problem.
  • It then couples the auxiliary problems and applies the preconditioned Krylov subspace methods.

    • Numerical Results for Reservoir Simulations


    East Beverly Hill Field

    ebeverly            ebeverly-result

    Black oil model: 83,592 (129 $\times$ 72 $\times$ 9) cells, 994 faults, 169 wells.



    JZ Oil Field

    jz9-3     
        
     jz9-3-result

    Polymer flooding: 474,297 cells, several faults, 37 wells.



    SPE 10 Benchmark

    spe10     

      spe10-result   

    Two phases (water and oil): 1.1 million cells, 5 wells.

    Reference: X. Hu, W. Liu, G. Qin, J. Xu, Y. Yan, and C. Zhang (2011).



    • Energy Storage


    • Lithium Ion Battery

    Lithiumion batteries are rechargeable, and they are characterized by lithium ions that move from the negative electrode to the positive electrode during discharge and then back again during charging.


    lithium-ion

    • Newton-Krylov-Multigrid Schemes for Lithium Ion Battery Simulation

    • Finite volume method
    • Newton’s method for the Butler-Volmer equation, and the whole nonlinear system
    • Krylov subspace method (GMRes) with block Gauss-Seidel preconditioner
    • Multigrid method for solving the Poisson-like problems in the preconditioner

    References: J. Wu, V. Srinivasan, X,  and C-Y, Wang (2002); J.Wu, X, and H. Zou (2006).



    • Fuel Cells

    A fuel cell is a device that converts a fuel’s chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most commonly used fuel for this purpose, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used.


    fuelcell-1           fuelcell-2

    Examples of fuel cells.

    • Robust Methods for Fuel Cells

    • Newton’s method for the nonlinear system
    • Kirchhoff transformation
    • Finite element-upwind finite volume method
    • Nonoverlapping Schwarz domain decomposition method
    • Overlapping domain decomposition method with non-matching grids
    • Newton-Krylov-based solvers

    • Numerical Results for Fuel Cells


    fuelcell-result

    Fast convergence within 21 iterations versus oscillatory/nonconvergent iterations using commercial CFD software.

    References: P.Sun, G. Xue, C-Y. Wang, and Xu (2008)P.Sun, G. Xue, C-Y. Wang, and Xu (2009); P.Sun, C-Y. Wang, and Xu (2010).



    • Solar Energy


    Solar cells are devices that convert solar energy into electricity. Solar energy is a renewable source. Therefore, it is environmentally friendly.


                
     solar cell 1                  solar cell 2

    Example of solar cells.