1887

Abstract

Summary

Fracture networks are heterogeneous systems creating anisotropic flow patterns, though field-scale flow models of fractured reservoirs use up-scaling of the fracture network to effective properties to model flow. We study the impact of upscaling aperture from a realistic aperture model, where aperture is defined by a stress-aperture relation that considers aperture variations within single fractures, to an arithmetically averaged distribution. This analysis is done through calculation of the equivalent permeability tensor of a discrete fracture and matrix flow model, taking into account different contrasts between fracture and matrix permeability. Results show that a strong equivalent permeability anisotropy emerges for a low matrix permeability, and that accurate representation of fracture aperture is as important as the fracture topology, particularly when the fracture matrix permeability ratio is large. The orientation of the permeability tensor varies with varying rock matrix permeability, reflecting anisotropy of the permeability that is impossible to extract from the fracture patterns itself. The results also highlight that utilizing a constant aperture for the fracture network may not reproduce the true anisotropy of the permeability. Utilizing an equivalent aperture in flow simulations introduces errors in both the direction and magnitude of principal permeabilities and the equivalent permeability anisotropy.

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/content/papers/10.3997/2214-4609.201800028
2018-02-05
2020-03-29
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References

  1. Aabø, T.M., Dramsch, J.S., Welch, M.J. and Lüthje, M.
    , [2017] Correlation of Fractures From Core, Borehole Images and Seismic Data in a Chalk Reservoir in the Danish North Sea. In 79th EAGE Conference and Exhibition 2017.
    [Google Scholar]
  2. Berkowitz, B.
    , [2002] Characterizing flow and transport in fractured geological media: A review. Advances in Water Resources, 25(8–12), 861–884.
    [Google Scholar]
  3. Hardebol, N.J., Maier, C., Nick, H., Geiger, S., Bertotti, G. and Boro, H.
    , [2015] Multiscale fracture network characterization and impact on flow: A case study on the Latemar carbonate platform. Journal of Geophysical Research: Solid Earth, 120(12), 8197–8222.
    [Google Scholar]
  4. Bisdom, K., Nick, H.M. and Bertotti, G.
    , [2017] An integrated workflow for stress and flow modelling using outcrop-derived discrete fracture networks. Computers & Geosciences, 103, 21–35.
    [Google Scholar]
  5. Bisdom, K., Bertotti, G. and Nick, H.M.
    , [2016a] The impact of in-situ stress and outcrop-based fracture geometry on hydraulic aperture and upscaled permeability in fractured reservoirs. Tectonophysics, 690, 63–75.
    [Google Scholar]
  6. , [2016b] A geometrically based method for predicting stress-induced fracture aperture and flow in discrete fracture networks. AAPG Bulletin, 100(7), 1075–1097.
    [Google Scholar]
  7. , [2016c] The impact of different aperture distribution models and critical stress criteria on equivalent permeability in fractured rocks. Journal of Geophysical Research: Solid Earth, 121(5), 4045–4063.
    [Google Scholar]
  8. Durlofsky, L.J.
    , [1991] Numerical calculation of equivalent grid block permeability tensors for heterogeneous porous media. Water Resource Research, 27, 699–708.
    [Google Scholar]
  9. Matthai, S.K. and Nick, H.M.
    [2009] Upscaling two-phase flow in naturally fractured reservoirs. AAPG bulletin, 93(11), 1621–1632.
    [Google Scholar]
  10. Nick, H.M., Paluszny, A., Blunt, M.J. and Matthai, S.K.
    , [2011] Role of geomechanically grown fractures on dispersive transport in heterogeneous geological formations. Physical Review E, 84(5).
    [Google Scholar]
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