Fast Generation of {3D} Discrete Fravture Networks in Respect of Geology

Laetitia Mace. ( 2005 )
in: Proc. 25th Gocad Meeting, Nancy

Abstract

During fracture modeling, Discrete Fracture Networks (DFNs) are simulated knowing each network’s key parameters : density, orientation, size and aperture. An efficient and generic stochastic simulation is developed to model all kinds of 3-D networks. No assumption is made on any of the individual fractures characteristics neither on their orientation nor on their size or shape. However, generated DFNs do not respect the geological constraints of fractures particularly the complex geometry and interaction between DFNs. On natural outcrops, the observed shape of each fracture depends on other geological features such as mechanical boundaries and other fracture sets. In this article, joint initiation and propagation processes are integrated into the DFNs generation. To build more realistic DFNs respecting geological constraints, a truncating post-processing is applied after the simulation. Three main truncation rules have to be satisfied. First, in a same set, fractures are stopped by each other avoiding crossings and enabling linkage. Second, they end on older fracture sets. Finally, fractures can abut on some characteristic discontinuities such as shale horizons. A fast and proficient method of truncation is developed for huge DFNs containing millions of fractures. This mandatory post-processing greatly modifies network connectivity and thus flow prediction through it.

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    BibTeX Reference

    @INPROCEEDINGS{Mace05GM,
        author = { Mace, Laetitia },
         title = { Fast Generation of {3D} Discrete Fravture Networks in Respect of Geology },
     booktitle = { Proc. 25th Gocad Meeting, Nancy },
          year = { 2005 },
      abstract = { During fracture modeling, Discrete Fracture Networks (DFNs) are simulated knowing each network’s
    key parameters : density, orientation, size and aperture. An efficient and generic stochastic
    simulation is developed to model all kinds of 3-D networks. No assumption is made on any of the
    individual fractures characteristics neither on their orientation nor on their size or shape. However,
    generated DFNs do not respect the geological constraints of fractures particularly the complex
    geometry and interaction between DFNs. On natural outcrops, the observed shape of each fracture
    depends on other geological features such as mechanical boundaries and other fracture sets. In this
    article, joint initiation and propagation processes are integrated into the DFNs generation. To build
    more realistic DFNs respecting geological constraints, a truncating post-processing is applied after
    the simulation. Three main truncation rules have to be satisfied. First, in a same set, fractures are
    stopped by each other avoiding crossings and enabling linkage. Second, they end on older fracture
    sets. Finally, fractures can abut on some characteristic discontinuities such as shale horizons. A fast
    and proficient method of truncation is developed for huge DFNs containing millions of fractures.
    This mandatory post-processing greatly modifies network connectivity and thus flow prediction
    through it. }
    }