Topology-Based Hydraulic Connectivity & Fracture Permeability by using Borehole Image Logs

Summary This study characterizes fracture networks in an exploration well in the Utsira High, northern North Sea, where fractures may provide fluid pathways in carbonates and granitic basement. Using high-resolution borehole images, fracture connectivity was quantitatively analyzed in different fracture zones. Fracture topological parameters were then integrated into hydraulic connectivity and fracture permeability calculations, applying a fuzzy-logic approach to account for uncertainties. Fifteen fracture zones were identified, with most surpassing the percolation threshold. Zones 2 and 3 had the highest hydraulic connectivity due to well-connected open fractures, while basement zones displayed increased fracture frequency and excellent connectivity, particularly in Zones 9 and 10. Permeability varied significantly across fracture zones, influenced by fracture geometry, mechanical rock properties, and alteration processes. The results highlight the importance of fracture topology in fluid flow prediction and reservoir characterization, improving permeability modeling and production strategies.