Modelling the Evolution of Natural Fracture Networks

Since completing his PhD at Birmingham University in 1997, Michael Welch has worked as an applied structural geologist in various consultancies and academic positions. His focus has always been on applied research in structural geology, developing new tools and techniques to solve specific problems, and working with industry to apply those techniques. This work has aimed to understanding and predicting the occurrence and effects of fractures and faults in the subsurface, mostly, but not exclusively, in the hydrocarbon industry. He has presented much of this work in publications and international conference presentations. Mikael Lthje did his PhD in geophysics and applied mathematics at Cambridge University, Technical University of Denmark and UCL in 2005. He has since then worked within academia, R&D and in the industry mostly with fractured reservoirs. He has also worked extensively with climate research, CO2 sequestration and fluid flow modelling. Simon Oldfield is a structural geologist with a background in geological modelling and model validation. Having previously worked in the mining and hydrocarbon industries, he undertook his PhD at the University of Leeds investigating the uncertainty of how seismic imaging represents different structural geometries observed in the field. Since 2019, he has worked with DHRTC calibrating and validating fracture modelling outputs against natural outcrops and considering the implications for subsurface fluid flow. The Danish Hydrocarbon Research and Technology Centre, based at the Technical University of Denmark, was set up in 2015 with funding from the hydrocarbon industry with a remit to carry out research to benefit the Danish offshore hydrocarbon industry. For the past 3 years, Michael and Mikael have been working on this project to develop new techniques to simulate natural fracture networks, for use in building improved fluid flow models of hydrocarbon fields. They have been working closely with Total E&P Denmark to apply these techniques to Danish offshore oil and gas fields, and have also applied them to several outcrops and a geothermal prospect. The techniques have potential applications in all fractured reservoirs and aquifers across industries including hydrocarbon extraction, geothermal energy, CO2 sequestration and underground storage.

Introduction.- Conceptual Model.- Modelling Microfractures.- Modelling Macrofractures.- Active and Static Fractures.- Elastic Moduli and Stress.- Controls on Fracture Evolution.- Some Outcrop Examples.- Application to the Subsurface.- Conclusions and Further Work.