Experimental investigations on the temperature and strain-rate dependence of failure and friction criteria for a porous sandstone
- 1Fraunhofer Research Institution for Energy and Geothermal Systems – IEG, Bochum, Germany (benedikt.ahrens@hs-bochum.de)
- 2Institute of Geology, Mineralogy, and Geophysics, Ruhr-Universität Bochum, Bochum, Germany
- 3Department of Civil and Environmental Engineering, Bochum University of Applied Sciences, Bochum, Germany
Understanding the deformation-related thermomechanical state of reservoir rocks under in-situ conditions is essential for modelling the stress distribution and stability of subsurface structures, for example associated with aftershock activity and induced seismicity. Commonly, reservoir modelling approaches make use of the generalized friction criterion according to Byerlee, which distinguishes between depths below and above approximately 6 km. However, numerous studies have shown that thermomechanical rock properties under elevated pressure and temperature conditions differ significantly from those at the surface and among rock types. The significant influence of the geothermal gradient on elastic and inelastic rock properties has already been demonstrated for temperature variations as low as 150 °C. Studies on the effect of in-situ stress and temperature conditions on post-failure behaviour and frictional properties are completely lacking.
In our experimental study we determined the thermomechanical properties of porous Ruhr sandstone samples during conventional triaxial deformation tests to derive stress- and temperature-dependent failure and friction criteria. Effective confining pressures and temperatures applied in the tests cover the range of in-situ conditions equivalent to depths up to three kilometres. Simultaneously, ultrasonic P- and S-wave measurements were performed to determine properties of ultrasound wave propagation (i.e. dynamic elastic properties) as a function of in-situ conditions. Triaxial deformation experiments were conducted at various strain rates to investigate the deformation-rate dependence of the failure and friction criteria and the correlation between dynamic and static elastic properties.
How to cite: Ahrens, B., Duda, M., and Saenger, E. H.: Experimental investigations on the temperature and strain-rate dependence of failure and friction criteria for a porous sandstone, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-15134, https://doi.org/10.5194/egusphere-egu2020-15134, 2020
How to cite: Ahrens, B., Duda, M., and Saenger, E. H.: Experimental investigations on the temperature and strain-rate dependence of failure and friction criteria for a porous sandstone, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-15134, https://doi.org/10.5194/egusphere-egu2020-15134, 2020
This abstract will not be presented.