Unfoldability versus incoherences

Cyril Galéra and Chakib Bennis and Isabelle Moretti and Jean-Laurent Mallet and C-C. Lecomte. ( 2001 )
in: $21^st$ Gocad Meeting Proceedings

Abstract

The construction of a 3D structural model is often based on seismic images more or less precise. In order to validate the model, the geologist usually restores it to check if it looks coherent in its initial state. The first interpretation may be directly unfoldable but also shows areas of incoherence. The geologist often has doubt about the non-unfoldability which could either be a real structural problem or an artefact. Indeed, if parts of the horizons are poorly imaged, the picking uncertainty leads to a geometry of the horizon containing many little bumps. These local features make the horizons not unfoldable. The current software packages are able to unfold a horizon or a layer preserving the area or volume, even if the horizon is not unfoldable. They overcome the unfolding creating distortions which are meaningless from a geological point of view. The new tool we have developed, allows the geologist to locate these zones of potential problems on the horizons, and then to locally correct the geometry to obtain a unfoldable horizon. If the geologist thinks the nonunfoldablility is due to a picking artefact, an automatic correction can be performed, producing a closer, smooth and unfoldable geometry. If the geologist estimates that this non-unfoldable geometry is, in reality, a zone of strong internal deformation, he may use the algorithm to isolate this part and restore it by another method than the flexural slip.

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    BibTeX Reference

    @inproceedings{Galera2001a,
     abstract = { The construction of a 3D structural model is often based on seismic images more or less precise. In order to
    validate the model, the geologist usually restores it to check if it looks coherent in its initial state. The first
    interpretation may be directly unfoldable but also shows areas of incoherence. The geologist often has doubt
    about the non-unfoldability which could either be a real structural problem or an artefact. Indeed, if parts of the
    horizons are poorly imaged, the picking uncertainty leads to a geometry of the horizon containing many little
    bumps. These local features make the horizons not unfoldable. The current software packages are able to unfold
    a horizon or a layer preserving the area or volume, even if the horizon is not unfoldable. They overcome the
    unfolding creating distortions which are meaningless from a geological point of view.
    The new tool we have developed, allows the geologist to locate these zones of potential problems on the
    horizons, and then to locally correct the geometry to obtain a unfoldable horizon. If the geologist thinks the nonunfoldablility
    is due to a picking artefact, an automatic correction can be performed, producing a closer, smooth
    and unfoldable geometry. If the geologist estimates that this non-unfoldable geometry is, in reality, a zone of
    strong internal deformation, he may use the algorithm to isolate this part and restore it by another method than
    the flexural slip. },
     author = { Galéra, Cyril AND Bennis, Chakib AND Moretti, Isabelle AND Mallet, Jean-Laurent AND Lecomte, C-C. },
     booktitle = { $21^st$ Gocad Meeting Proceedings },
     title = { Unfoldability versus incoherences },
     year = { 2001 }
    }