Fracture Visualization and Quantification Using Helical CT Scan Technology*

Fracture characteristics—such as orientation, type, fluid storage capability, and permeability—are complex yet essential information for understanding fractured reservoirs. Fractures are often perceived as permeable pathways, although many fractures partially or completely inhibit permeability within a reservoir. For example, opening-mode fractures (joints) may be partially or entirely sealed hindering flow along and/or across the joint plane. Mineral-fill percentage can be modeled using aperture and mineral-fill threshold data obtained from surrounding fractures and matrix, yet this is difficult to model for calcite, a common fracture-fill material. Fracture data obtained from core and image logs provides a direct test to structural and geomechanical models and reduces prediction errors for fracture orientation, type, and aperture. The ability to visualize fractures and fracture networks on a variety of scales is essential for an interpreter to predict these properties. Advances in computerized tomography (CT) technology in the medical industry has made 3D core imaging possible, opening up new opportunities for visualizing and quantifying complex fracture systems. Helical CT scanning (HCT) technology allows a user to model fracture attributes while preserving the integrity of valuable core samples. The use of HCT for fracture quantification and visualization greatly improves the understanding of the characteristics and behavior of dominant fracture sets within a fractured reservoir.