Automatic extraction of natural fracture traces from borehole images

Natural fractures may greatly affect wellbore stability and fluid flow in oil reservoirs. The detection of fracture heterogeneities-also named fracture traces-on electrical image logs is not yet efficiently automated and consequently requires long and tedious work from geologists. In this article, we propose an efficient fracture trace extraction algorithm that produces fast, efficient and repeatable results. Morphology operations are first applied to detect high contrast traces while controlling their geometry. A priori information about the geometry of sedimentary surfaces is then used to compute the main fracture orientation. Finally, a clustering algorithm is performed for grouping the extracted traces and identifying those that correspond to natural fractures.