3D modelling of fracture networks from DOM: variability of density in fracture corridors

Marien Kone and Sophie Viseur and Juliette Lamarche and Jules Fleury. ( 2018 )
in: 2018 Ring Meeting, ASGA

Abstract

Many studies were devoted to model diffuse fractures in 3D but few ones were focused on modelling the spatial organization of fractures in fracture corridors. Fracture corridors are particular geological structures within which the fracture density is particularly high. Recently, it was highlighted that the internal architecture of fracture corridors is more complex than expected. It is not only characterized by high fracture density, for instance: 1) the fracture density may vary within the fracture corridors, horizontally and vertically; 2) other geological structures such as breccia are also included in corridors; 3) lenticular zones of diffuse fractures may occur within the fracture corridor boundaries. Fracture corridors have major impacts on fluid flow in carbonate reservoirs. However, fractures are only observed along well data, i.e. 1D data. The 3D modelling of the fracture networks within fracture corridors is then of paramount importance to fill the gap between the 3D nature of these objects and the 1D available observations. In this study, 3D Digital Outcrop Models (DOM) were acquired from outcrops in the South-East of France. These numerical data were used as a support for interpreting and modelling fracture networks in order to study the fracture patterns in fracture corridors. Semi-automated techniques were used to extract fracture planes and traces Indeed, two cases exist: 1) the fracture planes belong to the outcrop surface geometry; 2) the fracture planes intersect the outcrop surface and draw a gutter or a line along the outcrop. In the first case, the objective is to extract the surface patch where the fracture plane is merged with the outcrop surface. In the second case, the aim is to extract the line corresponding to the fracture trace along the outcrop surface. This automatic procedure combined with field validation and common geomodelling approach allows accurate 3D models of fracture networks within a zone including diffuse fractures and fracture corridors. Then, it was possible to study the variability of the fracture density and other parameters of the fracture network. Synthetic scanlines were built from the 3D models and compared to the field scanlines according to the P10 (1D density). The objectives are both to show the potential missing modeled fractures compared to field data and to evaluate differences between 1D data, such as wells, and 3D networks.

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BibTeX Reference

@INPROCEEDINGS{,
    author = { Kone, Marien and Viseur, Sophie and Lamarche, Juliette and Fleury, Jules },
     title = { 3D modelling of fracture networks from DOM: variability of density in fracture corridors },
 booktitle = { 2018 Ring Meeting },
      year = { 2018 },
 publisher = { ASGA },
  abstract = { Many studies were devoted to model diffuse fractures in 3D but few ones were focused on modelling the spatial
organization of fractures in fracture corridors. Fracture corridors are particular geological structures within which the
fracture density is particularly high. Recently, it was highlighted that the internal architecture of fracture corridors is more
complex than expected. It is not only characterized by high fracture density, for instance: 1) the fracture density may vary
within the fracture corridors, horizontally and vertically; 2) other geological structures such as breccia are also included
in corridors; 3) lenticular zones of diffuse fractures may occur within the fracture corridor boundaries. Fracture corridors
have major impacts on fluid flow in carbonate reservoirs. However, fractures are only observed along well data, i.e. 1D
data. The 3D modelling of the fracture networks within fracture corridors is then of paramount importance to fill the gap
between the 3D nature of these objects and the 1D available observations.
In this study, 3D Digital Outcrop Models (DOM) were acquired from outcrops in the South-East of France. These
numerical data were used as a support for interpreting and modelling fracture networks in order to study the fracture
patterns in fracture corridors. Semi-automated techniques were used to extract fracture planes and traces Indeed, two
cases exist: 1) the fracture planes belong to the outcrop surface geometry; 2) the fracture planes intersect the outcrop
surface and draw a gutter or a line along the outcrop. In the first case, the objective is to extract the surface patch where
the fracture plane is merged with the outcrop surface. In the second case, the aim is to extract the line corresponding to
the fracture trace along the outcrop surface.
This automatic procedure combined with field validation and common geomodelling approach allows accurate 3D models
of fracture networks within a zone including diffuse fractures and fracture corridors. Then, it was possible to study the
variability of the fracture density and other parameters of the fracture network. Synthetic scanlines were built from the
3D models and compared to the field scanlines according to the P10 (1D density). The objectives are both to show the
potential missing modeled fractures compared to field data and to evaluate differences between 1D data, such as wells,
and 3D networks. }
}