Connectivity Index and Connectivity Field towards Fluid Flow in Fracture-based Geothermal Reservoirs

Abstract

Connectivity measures, such as the connectivity index and the connectivity field, are useful for determining preferential flow directions and flow pathways through fracture networks. However, the current implementation of these measures does not consider the hydraulic properties of the fracture network, which is the issue addressed in this work. We demonstrate that Darcy’s law can be incorporated into the evaluation of these measures using the persistence and aperture properties of fractures in the fracture network. We show that this incorporation can help determine more reliable and accurate flow pathways in the fracture network for three forms of aperture distributions: (i) constant aperture for each fracture cluster (pathway), (ii) variable aperture for each cluster and (iii) variable aperture for each fracture. We also introduce a new concept for the classification of pathways based on the reliability of their assessment, which enhances the understanding of the flow behaviour of fracture-based reservoirs as a result of fracture network expansion processes such as hydraulic stimulation.