Discrete Fracture Network Analyses and Modelling

Michael Munro

Discrete Fracture Network (DFN) modelling opens possibilities for more true-to-reality representations of fractured geological conditions in simulations of deformation, offering more informed design assessments for mining and civil engineering applications. The accuracy of these assessments however remains dependent on the realism of models they are based, where the fracture network topology plays a pivotal role in determining the geometry, connectivity, size distribution, and spatial arrangement of the fractures.

An overview is provided for the development of DFN technology over the years, in addition to a summary of the main modelling approaches and their respective limitations in terms of mimicking the complexities we are presented with in nature. Stochastic DFN examples are also compared with natural analogues to reinforce the importance of integrating key geological drivers in simulating geomechanical behaviour.

A new data-model driven protocol ‘DMX’ is presented for 3D DFN modelling, incorporating specific associations of discontinuities observed in nature using a specific set of dependencies and relationships. These mimic the controlling processes which have resulted in the observed pattern to make a geologically feasible model for more realistic fracture network representation in space. Example applications of the protocol are presented to illustrate a few of the unlimited combinations that can be generated in 3D space. Furthermore, an example of the complete workflow is provided based on the analyses of common borehole imaging and mapping sources, including calibration to real observed cases.

The presented methodology constitutes a major leap forward in data integration and model realism for simulating fractured rock behaviour. This opens a range of exciting technological challenges and opportunities which are also discussed.

About the speaker

Michael Munro Technical Director, GMEK

Michael has over 17 years’ experience in mining, geological, and geotechnical investigations. He has a strong passion for structural mapping and interpretation and applying this knowledge in 3D modelling for engineering assessments. Later in his career Michael managed Geological and Geotechnical Services, then Strategic Mine Planning and Survey functions for one of Australia’s largest open-cut mining operations. In 2021 Michael founded GMEK, and immediately began delivering the first of several breakthrough modelling solutions for ground characterisation. Michael is currently involved in presenting these new technologies to several technical forums and has recently co-authored his first paper on fracture modelling for a Geological Society of London – Special Publication. Michael continues to develop and provide these solutions to valued partners, helping them unlock a new world of possibilities in rock mechanics assessment with more true-to-life 3D modelling.

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