Fracture Population of Carbonate Geological Models Using Digital Outcrop Data

Bérengère Savary-Sismondini¹*, Erik Monsen¹, Aicha Bounaim¹, Anne Louise Larsen¹, Michael Nickel¹, Lars Sonneland¹, Dave Hunt², Paul Gillespie², and John Thurmond^2
1Schlumberger, Norway
²StatoilHydro
*[email protected]

The fluid-flow behaviour of carbonate reservoirs is, to a large degree, governed by the spatial configuration of discontinuities, particularly by the fracture network. The quantification of these discontinuities in subsurface data is highly challenging, in particular at an exploration stage when only seismic data might be available. We propose a novel methodology for populating fracture sets in carbonate geological models. The first step consists of extracting the stratigraphic and structural framework from the 3-D seismic. A 3-D stratigraphic method combined with ant-tracking allows the mapping of large-scale discontinuities and their associated attributes. This set of primitives is defined as a model repository. The second step is to populate the geological model with fracture sets by conditioning the discrete fracture network generation (DFN) on seismically observable features, such as horizon-folding (curvature) and fault displacement. The output fracture sets, generated by the DFN method, are tailored to the geomechanical history of the specific geological case by conditioning the DFN on characteristics of the fracture distributions extracted from analogues. A major challenge in the development of the new methodology was to extract and quantify the fracture distributions from the outcrops in an automated manner. The parameterization of the distributions was chosen to be the fracture length, orientation and density in relation to stratigraphy, lithology and fault characteristics. The integration of the simulated fractures into the geological model leads to the generation of a detailed mechanical stratigraphy model which is useful for further permeability tensor computation and flow simulation.

AAPG Search and Discovery Article #90077©2008 GEO 2008 Middle East Conference and Exhibition, Manama, Bahrain