A detailed description and understanding of fluid reservoir rocks is of great economic, environmental, and scientific interest, for example for CO2-sequestration, hydrocarbon exploration, nuclear waste disposal, or groundwater aquifer remediation. Such fluid reservoirs are commonly probed using seismic investigation methods. Because a large part of the reservoir porosity and permeability can be due to fractures, understanding their effects on the seismic response of a rock is therefore essential for a reliable rock characterization.
The project UPseis investigates seismic phenomena in fractured rocks, with a special focus on the so-called Krauklis wave. This special wave mode is bound to fluid-filled fractures. When propagating back and forth along a fracture, a Krauklis wave can emit a seismic signal to the surrounding rock with a characteristic frequency. When picked up at the Earth’s surface, such seismic signals may contain information on the fracture density, fracture orientation, or fluid type in the subsurface reservoir.
The Krauklis wave phenomenon will be studied in detail on the scale of individual fractures both by applying numerical wave-propagation simulations and in the laboratory. The results will then be upscaled to the reservoir-scale to better understand the bulk seismic response of fractured fluid reservoirs.
The following publications resulted directly from the UPseis-project:
- Bakker R.R., Frehner M. and Lupi M., 2016: How temperature-dependent elasticity alters host rock/magmatic reservoir models: A case study on the effects of ice-cap unloading on shallow volcanic systems, Earth and Planetary Science Letters 456, 16–25. Go to article
- Shih P.-J.R. and Frehner M., 2016: Laboratory evidence for Krauklis wave resonance in fractures and implications for seismic coda wave analysis, Geophysics 81, T285–T293. Go to article
- Zhong X., Frehner M., Kunze K. and Zappone A.S., 2015: A numerical and experimental investigation on seismic anisotropy of Finero peridotite, Ivrea-Verbano Zone, Northern Italy, in Materials Science and Engineering, Volume 82 of IOP Conference Series, 012072. Go to article
- Frehner M., 2014: Krauklis wave initiation in fluid-filled fractures by seismic body waves, Geophysics 79, T27–T35. Go to article
- Tisato N., Quintal B., Chapman S., Madonna C., Subramaniyan S., Frehner M., Saenger E.H. and Grasselli G., 2014: Seismic attenuation in partially saturated rocks: recent advances and future directions, The Leading Edge 33, 640–646. Go to article
- Zhong X., Frehner M., Kunze K. and Zappone A., 2014: A novel EBSD-based finite-element wave propagation model for investigating seismic anisotropy: Application to Finero Peridotite, Ivrea-Verbano Zone, Northern Italy, Geophysical Research Letters 41, 7105–7114. Go to article