SPEcial GTTS May 2026 webinar: How dynamic fracture modelling can characterize geothermal reservoirs

Abstract: Understanding the natural fracture networks is essential for efficient development of many geothermal reservoirs. However fractures in the subsurface cannot be imaged directly on geophysical data, and traditional stochastic methods of fracture modelling are often time-consuming and unreliable. Therefore researchers at the Danish Offshore Technology Centre have developed a tool for forward modelling the growth of fracture networks, based on the geological history of the units. This tool uses Linear Elastic Fracture Mechanics and Subcritical Fracture Propagation Theory to simulate the growth of networks containing hundreds of thousands of fractures, around large geological structures such as diapirs, major faults and plutons. It can generate more realistic fracture models more easily than stochastic modelling techniques. It can generate multiple geologically consistent realisations for uncertainty analysis and can predict key parameters such as fracture size and connectivity that are required inputs in stochastic models. As part of the EU Horizon funded Go-FORWARD project, we are adapting the tool to model reservoirs of particular importance to geothermal energy production, such as tight carbonates or crystalline basement rocks. We are calibrating the tool with field and subsurface data from producing geothermal reservoirs. In this talk we will look at a case study from Eclépens, Switzerland, where SGE is currently in the well-design phase of a deep geothermal project targeting the data-poor Muschelkalk Formation. By calibrating the workflow first on data-rich Lower Cretaceous intervals, we demonstrate the robustness of this physics-based approach and its potential for application to deeper reservoir intervals where direct constraints are limited. We will then show how we can replicate the fracture patterns observed in granites, using examples from Cornwall, SW England. ________________________________________ Key Learning Objectives • Geomechanically-based simulation of fracture growth. • Key geological and geomechanical controls on fracture density, distribution, size and connectivity. • Calibration of fracture models against field and subsurface data at different scales. ________________________________________ Speakers Bios: Dr Michael Welch completed his PhD at the University of Birmingham, UK, on the development of Mesozoic extensional basins in the southern Irish Sea. He has worked for over 20 years in academia and industry, as a researcher and consultant in structural geology and geomechanics. He worked at Rock Deformation Research in Leeds, UK, and then Schlumberger for 10 years on fault seal analysis and modelling, before joining the Danish Technical University in 2015, where developed models for predicting fracture networks in the subsurface. He is currently working on projects applying these techniques to Carbon Capture and Storage and to geothermal energy production. Lucy Salmon is a geologist at Swiss Geo Energy SA, working at the intersection of sedimentary geology, numerical modelling, and geothermal energy. She holds a Master’s degree in geosciences from the École Lémanique des Sciences de la Terre et de l’Environnement (ELSTE, University of Geneva). Her work focuses on testing, extending, and developing open-source modelling approaches as transparent and robust alternatives to proprietary workflows. Through this work, she aims to improve, promote, and disseminate these methods in order to reduce pre-drilling uncertainties and support the development of geothermal energy. At Swiss Geo Energy SA, she also contributes to applying these approaches to real geothermal projects.