Understanding the relationship between fracture initiation and propagation, induced seismicity and fluid flow is crucial for geothermal reservoir engineering, as these processes are closely linked to the production of the reservoir. Previous experiments at the 10-1,000 m scale have revealed key concepts for managing induced seismicity and enhancing permeability (Schill et al., 2017; Zang et al., 2017). RockBlockEx, a new laboratory half-meter scale experiment, allows hydraulic fracturing experiments at realistic differential stress. This setup allows 3D localization of fracture-related processes through a dense distribution of sensors. The apparatus consists of an exchangeable rock block integrated into a stainless-steel frame that applies differential confinement pressure from three directions through flat jacks. An injection well and up to four production wells can be drilled into the rock block. Sensors monitor pressure, temperature, acoustic emissions and self-potential (SP) signals. Additionally, fiber optic cables can be installed. Besides hydromechanical interaction, RockBlockEx is designed to investigate SP response to hydraulic fracturing. Previous studies have shown correlations of SP with pressure drop and SP during fracturing and circulation phases at lab scale (Hu et al., 2020), with induced seismicity during injection and during shut-in phases at reservoir scale (Marquis et al., 2002), as well as poroelastic response to hydraulic fracturing at underground laboratory scale (Haaf et al., subm.). RockBlockEx allows for investigating such effects under controlled laboratory conditions and repeatable.

Press the Back button in your browser, or search again.

Copyright 2025, Stanford Geothermal Program: Readers who download papers from this site should honor the copyright of the original authors and may not copy or distribute the work further without the permission of the original publisher.