Characterization of fracture corridors from digital outcrop by combining automatic detection approaches with field analysis

Abstract

Numerical outcrops are key data for modeling the 3D spatial organization of fractures. Many studies were devoted to model diffuse fractures in 3D but few ones were focused on modelling the spatial organization of 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: 1) the fracture density may vary within the fracture corridors; 2) other geological structures such as breccia are also encountered. Fractures have major impacts on fluid flow in carbonate. Geostatistical approaches were proposed to generate 3D fracture networks for reservoir characterization. They require information about fracture size, orientation and density. As only 1D data are available in subsurface studies, 3D fracture models obtained from outcrop studies are then of paramount importance for reservoir analog characterization. In this study, 3D Digital Outcrop Models (DOM) were acquired from outcrops in the South-East of France. They were used as a support for interpreting and modelling fracture networks to study the fracture patterns in fracture corridors. Semi-automated techniques were proposed to extract fracture planes and traces from DOM. This dataset was used to constrain 3D models of fractures.