TY - JOUR
T1 - Experimental Poroviscoelasticity of Common Sedimentary Rocks
AU - Makhnenko, Roman Y.
AU - Podladchikov, Yury Y.
N1 - Funding Information:
We thank Joe Labuz for permission to publish the results of plane strain compression tests. Christophe Nussbaum and Swisstopo are acknowledged for providing Opalinus clay cores. Research by R.Y. Makhnenko was supported as part of the Center for Geologic Storage of CO2, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under award DE-SC0C12504. Susan Krusemark edited the manuscript. Data displayed or used to generate figures and plots are available as supporting information.
PY - 2018/9
Y1 - 2018/9
N2 - The success of geoenergy applications such as petroleum recovery or geological storage of CO2 depends on properly addressing the physical coupling between the pore fluid diffusion and mechanical deformation of the subsurface rock. Constitutive models should include short-term hydromechanical interactions and long-term behavior and should incorporate the principles behind the mathematical models for poroelastic and poroviscoelastic responses. However, the viscous parameters in constitutive relationships still need to be validated and estimated. In this work, we experimentally quantify the time-dependent response of fluid-filled sedimentary rocks at room temperature and isotropic stress states. Drained, undrained, and unjacketed geomechanical tests are performed to measure the poroelastic parameters for Berea sandstone, Apulian limestone, clay-rich material, and Opalinus clay (shale). A poroviscous model parameter, the bulk viscosity, is included in the constitutive relationships. The bulk viscosity is estimated under constant isotropic stress conditions from time-dependent deformation of rock in the drained regime for timescales ~105 s and from observations of the pore pressure growth under undrained conditions at timescales of ~104 s. The bulk viscosity is on the order of 1015–1016 Pa s for sandstone, limestone, and shale and ~1013 Pa s for clay-rich material, and it decreases with an increase in pore pressure despite a corresponding decrease in the effective stress. In the long term, fluid pressure can asymptotically approach minimum principal stress, which in natural reservoirs may lead to liquefaction or rock embrittlement, causing slip instabilities and earthquakes and creating high-permeability channels in low-permeable rock.
AB - The success of geoenergy applications such as petroleum recovery or geological storage of CO2 depends on properly addressing the physical coupling between the pore fluid diffusion and mechanical deformation of the subsurface rock. Constitutive models should include short-term hydromechanical interactions and long-term behavior and should incorporate the principles behind the mathematical models for poroelastic and poroviscoelastic responses. However, the viscous parameters in constitutive relationships still need to be validated and estimated. In this work, we experimentally quantify the time-dependent response of fluid-filled sedimentary rocks at room temperature and isotropic stress states. Drained, undrained, and unjacketed geomechanical tests are performed to measure the poroelastic parameters for Berea sandstone, Apulian limestone, clay-rich material, and Opalinus clay (shale). A poroviscous model parameter, the bulk viscosity, is included in the constitutive relationships. The bulk viscosity is estimated under constant isotropic stress conditions from time-dependent deformation of rock in the drained regime for timescales ~105 s and from observations of the pore pressure growth under undrained conditions at timescales of ~104 s. The bulk viscosity is on the order of 1015–1016 Pa s for sandstone, limestone, and shale and ~1013 Pa s for clay-rich material, and it decreases with an increase in pore pressure despite a corresponding decrease in the effective stress. In the long term, fluid pressure can asymptotically approach minimum principal stress, which in natural reservoirs may lead to liquefaction or rock embrittlement, causing slip instabilities and earthquakes and creating high-permeability channels in low-permeable rock.
KW - Opalinus clay
KW - bulk viscosity
KW - creep
KW - poroelasticity
KW - shale
KW - undrained response
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U2 - 10.1029/2018JB015685
DO - 10.1029/2018JB015685
M3 - Article
AN - SCOPUS:85053801739
VL - 123
SP - 7586
EP - 7603
JO - Journal of Geophysical Research D: Atmospheres
JF - Journal of Geophysical Research D: Atmospheres
SN - 0148-0227
IS - 9
ER -