TY - GEN
T1 - Thermal effect on long-term shale behavior in nuclear waste storage
AU - Makhnenko, R. Y.
AU - Kim, H.
AU - Kim, K.
N1 - Publisher Copyright:
© 2023 57th US Rock Mechanics/Geomechanics Symposium. All Rights Reserved.
PY - 2023
Y1 - 2023
N2 - Shale-like formations can serve as barriers for geologic disposal of high-level nuclear waste. Adopting these tight materials has an advantage that any radionuclides emitted from the canisters would stay with hardly mobile pore water within the rock. However, there are a few issues associated with the sealing capacity of shales as high temperatures experienced in nuclear waste disposal can strongly affect their geomechanical and flow properties. In this study, we investigate how the continuous heating and hydromechanical loading are affecting the flow properties of a shale with the clay content above 50% and the dominant pore size on the order of tens of nanometers. Both intact and fractured specimens are considered, and parameters associated with a coupled hydromechanical model are measured in high-pressure laboratory experiments, including the time-dependent deformation introduced to the model through bulk viscosity. It appears that even a small increase in temperature from 24℃ to 40℃ significantly impacts long-term (viscoelastic) response of shale, while the effect on the short-term (poroelastic) behavior is less pronounced. At the same time, the thermal effect on the fluid flow is ambiguous: the permeability increases with temperature but is predicted to eventually decrease due to the accelerated rock compaction at elevated temperatures.
AB - Shale-like formations can serve as barriers for geologic disposal of high-level nuclear waste. Adopting these tight materials has an advantage that any radionuclides emitted from the canisters would stay with hardly mobile pore water within the rock. However, there are a few issues associated with the sealing capacity of shales as high temperatures experienced in nuclear waste disposal can strongly affect their geomechanical and flow properties. In this study, we investigate how the continuous heating and hydromechanical loading are affecting the flow properties of a shale with the clay content above 50% and the dominant pore size on the order of tens of nanometers. Both intact and fractured specimens are considered, and parameters associated with a coupled hydromechanical model are measured in high-pressure laboratory experiments, including the time-dependent deformation introduced to the model through bulk viscosity. It appears that even a small increase in temperature from 24℃ to 40℃ significantly impacts long-term (viscoelastic) response of shale, while the effect on the short-term (poroelastic) behavior is less pronounced. At the same time, the thermal effect on the fluid flow is ambiguous: the permeability increases with temperature but is predicted to eventually decrease due to the accelerated rock compaction at elevated temperatures.
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U2 - 10.56952/ARMA-2023-0908
DO - 10.56952/ARMA-2023-0908
M3 - Conference contribution
AN - SCOPUS:85177869926
T3 - 57th US Rock Mechanics/Geomechanics Symposium
BT - 57th US Rock Mechanics/Geomechanics Symposium
PB - American Rock Mechanics Association (ARMA)
T2 - 57th US Rock Mechanics/Geomechanics Symposium
Y2 - 25 June 2023 through 28 June 2023
ER -