Integration of Fracture Data into {3D} Geomechanical Modeling to Enhance Fractured Reservoirs Characterization

in: SPE 95827 Presented at the SPE ATCE, Dallas, Texas, U.S.A., October 9-12, pages 9

Abstract

Natural fractures have a dramatic impact on reservoirs in terms of oil recovery because they often control the hydraulic flow as conductors (open fractures) or barriers (sealed fractures). However, fracture parameters are poorly constrained by reservoir data, due to the low seismic resolution and to the clustering of 1D data along wells. To enhance flow prediction, we suggest improving the characterization of Naturally Fractured Reservoirs by integrating well data with the history of stresses obtained by three-dimensional structural restoration (3D balanced unfolding). When unfolding a layer, boundary conditions are applied to mesh displacements to unfold the upper horizon and remove the latest brittle and ductile deformation increment. A linear isotropic elastic model governs restoration behavior, accounting for mechanical contrasts in the reservoir. Threedimensional strains and stresses are derived from these displacements. Orientation of theoretical tectonic fractures is then geomechanically deduced from the principal strain directions. Moreover, the orientations of fractures observed at wells (cores or image logs) provide implicit information on the principal directions of paleo-stress. Considering a given failure criterion, the observed fracture orientation is used to constrain the relative directions of paleo-stress components. Through this original approach, the 3D deformation is calibrated by observed geological data. Therefore, the hybrid geometrical and geomechanical restoration that has been developed accounts for reservoir heterogeneities and is globally constrained by paleo-stresses deduced from fractures observed along wells. This methodology is applied to a real reservoir located in North America and the strains predicted are used to generate 3D Discrete Fracture Networks. The key benefit of this approach, as compared to conventional methods, is to enhance fracture characterization by directly integrating observed fracture data into the geomechanical process.

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    BibTeX Reference

    @INPROCEEDINGS{Mace:05,
        author = { Mace, Laetitia and Muron, Pierre and Mallet, Jean-Laurent },
         title = { Integration of Fracture Data into {3D} Geomechanical Modeling to Enhance Fractured Reservoirs Characterization },
         month = { 9-12 October 2005 },
     booktitle = { SPE 95827 Presented at the SPE ATCE, Dallas, Texas, U.S.A., October 9-12 },
          year = { 2005 },
         pages = { 9 },
       address = { Dallas, Texas, U.S.A. },
      abstract = { Natural fractures have a dramatic impact on reservoirs in terms of oil recovery because they often control the hydraulic flow as conductors (open fractures) or barriers (sealed fractures). However, fracture parameters are poorly constrained by reservoir data, due to the low seismic resolution and to the clustering of 1D data along wells. To enhance flow prediction, we suggest improving the characterization of Naturally Fractured Reservoirs by integrating well data with the history of stresses obtained by three-dimensional structural restoration (3D balanced unfolding). When unfolding a layer, boundary conditions are applied to mesh displacements to unfold the upper horizon and remove the latest brittle and ductile deformation increment. A linear isotropic elastic model governs restoration behavior, accounting for mechanical contrasts in the reservoir. Threedimensional strains and stresses are derived from these displacements. Orientation of theoretical tectonic fractures is then geomechanically deduced from the principal strain directions. Moreover, the orientations of fractures observed at wells (cores or image logs) provide implicit information on the principal directions of paleo-stress. Considering a given failure criterion, the observed fracture orientation is used to constrain the relative directions of paleo-stress components. Through this original approach, the 3D deformation is calibrated by observed geological data. Therefore, the hybrid geometrical and geomechanical restoration that has been developed accounts for reservoir heterogeneities and is globally constrained by paleo-stresses deduced from fractures observed along wells. This methodology is applied to a real reservoir located in North America and the strains predicted are used to generate 3D Discrete Fracture Networks. The key benefit of this approach, as compared to conventional methods, is to enhance fracture characterization by directly integrating observed fracture data into the geomechanical process. }
    }