TY - JOUR
T1 - Relationships between fault characteristics and seismic responses in a large lab-scale tri-axial injection test conducted on a faulted Castlegate Sandstone
AU - Babarinde, Oladipupo
AU - Stanchits, Sergey
AU - Bauer, Robert
AU - Frailey, Scott
AU - Oye, Volker
AU - Sweet, Dustin
N1 - This work was supported as part of the Center for Geologic Storage, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under award number DE-SC0C12504. The authors would like to thank Pierre Cerasi and Nicholas Seprodi for their valuable contribution to the success of the large-scale block experiment. The authors would also like to thank Steve Whittaker and Hannes Leetaru for providing constructive reviews and comments, Ankit Verma for his contribution to the analysis of the laser-scanned data, and Sarah Grannis for her contribution in the grain-size analysis. We also acknowledge Schlumberger Carbon Services for donation of the Petrel E&P software platform.
This work was supported as part of the Center for Geologic Storage, an Energy Frontier Research Center funded by the U.S. Department of Energy , Office of Science , Basic Energy Sciences , under award number DE-SC0C12504 . The authors would like to thank Pierre Cerasi and Nicholas Seprodi for their valuable contribution to the success of the large-scale block experiment. The authors would also like to thank Steve Whittaker and Hannes Leetaru for providing constructive reviews and comments, Ankit Verma for his contribution to the analysis of the laser-scanned data, and Sarah Grannis for her contribution in the grain-size analysis. We also acknowledge Schlumberger Carbon Services for donation of the Petrel E&P software platform.
PY - 2022/9
Y1 - 2022/9
N2 - To investigate mechanisms causing microseismicity (Mw < 2) at a CO2 injection site, a large-scale triaxial block experiment was carried out on a faulted (saw-cut) cubic-meter of Castlegate Sandstone. The experiment consisted of injection tests at varying differential stresses, while monitoring and recording pore pressure and acoustic emissions (AEs). During the experiment, ∼33,000 AEs and ∼14 mm of horizontal displacement/slip, like a strike-slip fault movement, occurred. To understand the AE responses and ascertain fault characteristics near the located AEs, we modeled the topography of the fault surface, fault aperture, and fault-gouge thickness using pre- and post-experiment laser scans of the fault surface on each half of the block. Additionally, we characterized surface roughness parallel and perpendicular to slip. Models show crushing and flattening of the fault surfaces can be linked to the spatiotemporal distribution of AEs within 50 mm of the fault surface. Approximately 65% of AEs were in areas with small aperture (≤300 μm); thicker fault gouge was observed in adjacent areas with wider aperture and shows a two-fold reduction in grain size relative to unaltered Castlegate Sandstone. This work provides a conceptual understanding on fault surface evolution, which can be applied towards modeling of seismic slip.
AB - To investigate mechanisms causing microseismicity (Mw < 2) at a CO2 injection site, a large-scale triaxial block experiment was carried out on a faulted (saw-cut) cubic-meter of Castlegate Sandstone. The experiment consisted of injection tests at varying differential stresses, while monitoring and recording pore pressure and acoustic emissions (AEs). During the experiment, ∼33,000 AEs and ∼14 mm of horizontal displacement/slip, like a strike-slip fault movement, occurred. To understand the AE responses and ascertain fault characteristics near the located AEs, we modeled the topography of the fault surface, fault aperture, and fault-gouge thickness using pre- and post-experiment laser scans of the fault surface on each half of the block. Additionally, we characterized surface roughness parallel and perpendicular to slip. Models show crushing and flattening of the fault surfaces can be linked to the spatiotemporal distribution of AEs within 50 mm of the fault surface. Approximately 65% of AEs were in areas with small aperture (≤300 μm); thicker fault gouge was observed in adjacent areas with wider aperture and shows a two-fold reduction in grain size relative to unaltered Castlegate Sandstone. This work provides a conceptual understanding on fault surface evolution, which can be applied towards modeling of seismic slip.
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U2 - 10.1016/j.jsg.2022.104684
DO - 10.1016/j.jsg.2022.104684
M3 - Article
AN - SCOPUS:85135936270
SN - 0191-8141
VL - 162
JO - Journal of Structural Geology
JF - Journal of Structural Geology
M1 - 104684
ER -