1887

Abstract

Summary

Modelling fluid flow in highly heterogeneous and fractured reservoirs is a challenging task. These reservoirs typically have a complex structure with large and sharp variations in their material properties. Node Control Volume Finite Element (NCVFE) has been used to model those types of reservoirs at the fracture scale for the last decade. However, since the control volumes are constructed around the nodes and the material properties are assigned on elements, there is a loss of accuracy and associated fluid smearing when modelling multi-phase flows. We present a new numerical method to improve the modelling of multi-phase fluid flow in these reservoirs, called Interface Control Volume Finite Element (ICVFE). The method drastically decreases the smearing effects observed with other CVFE methods, such as NCVFE, while being mass conservative and numerically consistent. The pressure is computed at the interfaces of elements, and the control volumes are constructed around them, instead of at the element nodes. This assures that a control volume straddles, at most, two elements, which decreases the fluid smearing between neighbouring elements when large variations in their material properties are present. Lowest order Raviart-Thomas vectorial basis functions are used for the pressure calculation, and Lagrange basis functions are used to compute fluxes. The method is a combination of Mixed Hybrid Finite Element (MHFE) and FE methods. Its accuracy and convergence are tested using three dimensional tetrahedral elements to represent heterogeneous and fractured reservoirs. Our new approach is shown to be more accurate than current methods in the literature.

Significance

  • The ICVFE produces less unphysical flows than NCVFE while honouring the material properties of the domain.
  • It also models more accurate fluid saturation profiles than NCVFE.
  • The ICVFE method defines the primary variables (pressure and saturation) on the interfaces of elements. Therefore, it computes a high resolution of the primary variables over the finite element mesh (the number of interfaces is larger than the number of elements). This down-scaling is attractive and convenient since the truncated numerical errors decrease with the increase of degrees of freedom, and conventionally this is achieved by refining the mesh.

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/content/papers/10.3997/2214-4609.20141840
2014-09-08
2024-04-16
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References

  1. Abushaikha, A.
    (2013). Numerical Methods for Modelling Fluid Flow in Highly Heterogeneous and Fractured Reservoirs. London: United Kingdom: Ph.D. Thesis, Imperial College London.
    [Google Scholar]
  2. Bazar-Afkan, S., & Matthai, S.
    (2011). A new hybrid simulation method for multiphase flow on unstructured grids with discrete representations of matrial interfaces. IAMG.
    [Google Scholar]
  3. Chavent, G., & Roberts, J.
    (1991). A unified physical presentation of mixed, mixed-hybrid finite elements and standard finite difference approximations for the determination of velocities in water flow problems. Advances in Water Resources, 14(6), 329–348.
    [Google Scholar]
  4. Courant, R.
    (1943). Variational methods for the solution of problems of equilibrium and vibrations. Bulletin of the American Mathematical Society, 49, 23–.
    [Google Scholar]
  5. Durlofsky, L.
    (1993). A triangle based mixed finite-element-finite volume technique for modelling two phase flow through porous media. Journal of Computational Physics, 105(2), 252–266.
    [Google Scholar]
  6. Eymard, R., & Gallouet, T.
    (1989). Hybrid finite element techniques for oil recovery simulation. Computer Methods in Applied Mechanics and Engineering, 74(1), 83–98.
    [Google Scholar]
  7. Fung, L., Hieben, A., & Nshiera, L.
    (1991). Reservoir simulation with a control volume finite-element method. SPE Reservoir Engineering, 7(3), 349–357.
    [Google Scholar]
  8. Geiger, S., Roberts, S., Matthai, S., Zoppou, C., & Burri, A.
    (2004). Combining finite element and finite volume methods for efficient multiphase flow simulation in highly heterogenous and sturcturally complex geological media. Geofluids, 4(4), 284–299.
    [Google Scholar]
  9. Hoteit, H., & Firoozabadi, A.
    (2008). Numerical modeling of two-phase flow in heterogeneous permeable media with different capillarity pressures. Advances in Water Resources, 31, 73–.
    [Google Scholar]
  10. Huber, R., & Helmig, R.
    (1999). Multi-phase flow in heterogeneous porous media: A classical finite element method versus an implicit pressure- explicit saturation- based mixed finite element- fintie volume approach. International Journal for Numerical Methods in Fluids, 29(8), 899–920.
    [Google Scholar]
  11. Janicke, L., & Kost, A.
    (1996). Error Estimation and Adaptive Mesh Generation in the 2D and 3D Finite Element Method. TRANSACTIONS ON MAGNETICS, 32(3), 1334–1337.
    [Google Scholar]
  12. Nick, H., & Matthai, S.
    (2011). A hybrid finite-element finite-volume method with embedded discontinuities for solute transport in heterogenous media. Vadose Zone Journal, 10(1), 299–312.
    [Google Scholar]
  13. Raviart, P., & Thomas, J.
    (1977). A mixed finite element method for second order elliptic problems. Lectures Notes in Mathematics, 606, 315–.
    [Google Scholar]
  14. Schmid, K., Geiger, S., & Sorbie, K.
    (2013). Higher order FE–FV method on unstructured grids for transport and two-phase flow with variable viscosity in heterogeneous porous media. Journal of Computational Physics, 241, 444–.
    [Google Scholar]
  15. Voller, V. R.
    (2009). Basic Control Volume Finite Element Methods for Fluids and Solids. Singapore: World Scientific Publishing Co. Pte. Ltd.
    [Google Scholar]
  16. Younes, A., Ackerer, P., & Chavent, G.
    (2004). From mixed finite elements to finite volumes for elliptic PDEs in two and three dimensions. International Journal for Numerical Methods in Engineering, 59(3), 365–388.
    [Google Scholar]
  17. Younes, A., Mose, R., Ackerer, P., & Chavent, G.
    (1999). A new formulation of mixed finite element method for solving elliptic and parabolic PDE with triangular elements. Journal of Computational Physics, 149(1), 148–167.
    [Google Scholar]
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