A viscoplastic model of creep in shale
© 2020 Society of Exploration Geophysicists. We have developed a viscoplastic model that reproduces creep behavior and inelastic deformation of rock during loading-unloading cycles. We use a Perzyna-type description of viscous deformation that derives from a maximization of dissipated energy during...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Society of Exploration Geophysicists
2021
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| Online Access: | https://hdl.handle.net/1721.1/132990 |
| _version_ | 1811080082911920128 |
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| author | Haghighat, Ehsan Rassouli, Fatemeh S Zoback, Mark D Juanes, Ruben |
| author2 | Massachusetts Institute of Technology. Department of Civil and Environmental Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Civil and Environmental Engineering Haghighat, Ehsan Rassouli, Fatemeh S Zoback, Mark D Juanes, Ruben |
| author_sort | Haghighat, Ehsan |
| collection | MIT |
| description | © 2020 Society of Exploration Geophysicists. We have developed a viscoplastic model that reproduces creep behavior and inelastic deformation of rock during loading-unloading cycles. We use a Perzyna-type description of viscous deformation that derives from a maximization of dissipated energy during plastic flow, in combination with a modified Cam-clay model of plastic deformation. The plastic flow model is of the associative type, and the viscous deformation is proportional to the ratio of driving stress and a material viscosity. Our model does not rely on any explicit time parameters; therefore, it is well-suited for standard and cyclic loading of materials. We validate the model with recent triaxial experiments of time-dependent deformation in clay-rich (Haynesville Formation) and carbonate-rich (Eagle Ford Formation) shale samples, and we find that the deformation during complex, multiscale loading-unloading paths can be reproduced accurately. We elucidate the role and physical meaning of each model parameter, and we infer their value from a gradient-descent minimization of the error between simulation and experimental data. This inference points to the large, and often unrecognized, uncertainty in the preconsolidation stress, which is key to reproducing the observed hysteresis in material deformation. |
| first_indexed | 2024-09-23T11:25:32Z |
| format | Article |
| id | mit-1721.1/132990 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T11:25:32Z |
| publishDate | 2021 |
| publisher | Society of Exploration Geophysicists |
| record_format | dspace |
| spelling | mit-1721.1/1329902024-06-05T23:28:54Z A viscoplastic model of creep in shale Haghighat, Ehsan Rassouli, Fatemeh S Zoback, Mark D Juanes, Ruben Massachusetts Institute of Technology. Department of Civil and Environmental Engineering Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences © 2020 Society of Exploration Geophysicists. We have developed a viscoplastic model that reproduces creep behavior and inelastic deformation of rock during loading-unloading cycles. We use a Perzyna-type description of viscous deformation that derives from a maximization of dissipated energy during plastic flow, in combination with a modified Cam-clay model of plastic deformation. The plastic flow model is of the associative type, and the viscous deformation is proportional to the ratio of driving stress and a material viscosity. Our model does not rely on any explicit time parameters; therefore, it is well-suited for standard and cyclic loading of materials. We validate the model with recent triaxial experiments of time-dependent deformation in clay-rich (Haynesville Formation) and carbonate-rich (Eagle Ford Formation) shale samples, and we find that the deformation during complex, multiscale loading-unloading paths can be reproduced accurately. We elucidate the role and physical meaning of each model parameter, and we infer their value from a gradient-descent minimization of the error between simulation and experimental data. This inference points to the large, and often unrecognized, uncertainty in the preconsolidation stress, which is key to reproducing the observed hysteresis in material deformation. 2021-10-15T17:36:54Z 2021-10-15T17:36:54Z 2020-04 2018-10 2021-10-15T14:51:40Z Article http://purl.org/eprint/type/JournalArticle 0016-8033 1942-2156 https://hdl.handle.net/1721.1/132990 Ehsan Haghighat, Fatemeh S. Rassouli, Mark D. Zoback, and Ruben Juanes, A viscoplastic model of creep in shale, GEOPHYSICS 2020 85:3 en 10.1190/GEO2018-0700.1 GEOPHYSICS Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Society of Exploration Geophysicists other univ website |
| spellingShingle | Haghighat, Ehsan Rassouli, Fatemeh S Zoback, Mark D Juanes, Ruben A viscoplastic model of creep in shale |
| title | A viscoplastic model of creep in shale |
| title_full | A viscoplastic model of creep in shale |
| title_fullStr | A viscoplastic model of creep in shale |
| title_full_unstemmed | A viscoplastic model of creep in shale |
| title_short | A viscoplastic model of creep in shale |
| title_sort | viscoplastic model of creep in shale |
| url | https://hdl.handle.net/1721.1/132990 |
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