Exploring the impact of fracture interaction on connectivity and flow channelling using grown fracture networks

Abstract

Quantitative assessment of the flow properties and mechanical stability of naturally fractured rock is frequently practiced across the mining, petroleum, geothermal, geological disposal, construction, and environmental remediation industries. These fluid and mechanical behaviours are strongly influenced by the connectivity of the fracture system and the size of the intact rock blocks. However, these are amongst the more difficult fracture system properties to characterise and honour in numerical simulations. Nonetheless, they are still the product of interactions between fractures that can be conceptualised as a series of deformation events following geomechanical principles. Generating numerical models of fracture networks by simulating this deformation with a coupled and evolving rock mass and stress field is a significant undertaking. Instead, large scale fracture network models can be ‘grown’ dynamically according to rules that mimic the underlying mechanical processes and deformation history. This paper explores a computationally efficient rules-based method to generate fracture networks, demonstrates how different types of fracture patterns can be simulated, and illustrates how inclusion of fracture interactions can affect flow and mechanical properties. Relative to methods without fracture interaction and in contrast to some other rules-based approaches, the method described here regularises and increases fracture connectivity and decreases flow channelling.