Characterization of meso-scale mechanical properties of Longmaxi shale using grid microindentation experiments
© 2021 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences Mechanical properties, such as the hardness H, Young's modulus E, creep modulus C, and fracture toughness Kc, are essential parameters in the design of hydraulic fracturing systems for prospective shale gas formations. In...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier BV
2021
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| Online Access: | https://hdl.handle.net/1721.1/133114 |
| _version_ | 1811073981209378816 |
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| author | Du, J Whittle, AJ Hu, L Divoux, T Meegoda, JN |
| author2 | Massachusetts Institute of Technology. Department of Civil and Environmental Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Civil and Environmental Engineering Du, J Whittle, AJ Hu, L Divoux, T Meegoda, JN |
| author_sort | Du, J |
| collection | MIT |
| description | © 2021 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences Mechanical properties, such as the hardness H, Young's modulus E, creep modulus C, and fracture toughness Kc, are essential parameters in the design of hydraulic fracturing systems for prospective shale gas formations. In this study, a practical methodology is presented for obtaining these properties through microindentation experiments combined with quantitative observations of the mineralogical phases using X-ray diffraction (XRD), scanning electron microscopy (SEM) with backscattered electron (BSE) imaging, and energy-dispersive X-ray spectroscopy (EDS) analyses. We apply this method in the case of three types of Longmaxi shales with different mineralogies (i.e. carbonate-, clay-, and quartz-rich, respectively), which allows us to determine the characteristic indentation depth, hc = 8–10 μm, beyond which the mechanical response of the carbonate-rich shale is homogeneous and independent of its complex heterogeneous microstructure. Moreover, exploiting the results of a large number of indentation tests, we demonstrate that the indentation modulus M of the shale increases as a power-law of hardness H, and its creep modulus C increases linearly with H. We also compute the fracture toughness Kc from the indentation data by assuming a perfectly plastic behavior of the sample. Our results are in good agreement with independent measurements of Kc determined by microscratch tests. Finally, further tests on quartz- and clay-rich samples of the Longmaxi shale suggest further variations in the samples’ mechanical properties depending on their burial conditions and the mechanical properties of their dominant mineral phases. |
| first_indexed | 2024-09-23T09:41:11Z |
| format | Article |
| id | mit-1721.1/133114 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T09:41:11Z |
| publishDate | 2021 |
| publisher | Elsevier BV |
| record_format | dspace |
| spelling | mit-1721.1/1331142024-06-06T14:13:56Z Characterization of meso-scale mechanical properties of Longmaxi shale using grid microindentation experiments Du, J Whittle, AJ Hu, L Divoux, T Meegoda, JN Massachusetts Institute of Technology. Department of Civil and Environmental Engineering © 2021 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences Mechanical properties, such as the hardness H, Young's modulus E, creep modulus C, and fracture toughness Kc, are essential parameters in the design of hydraulic fracturing systems for prospective shale gas formations. In this study, a practical methodology is presented for obtaining these properties through microindentation experiments combined with quantitative observations of the mineralogical phases using X-ray diffraction (XRD), scanning electron microscopy (SEM) with backscattered electron (BSE) imaging, and energy-dispersive X-ray spectroscopy (EDS) analyses. We apply this method in the case of three types of Longmaxi shales with different mineralogies (i.e. carbonate-, clay-, and quartz-rich, respectively), which allows us to determine the characteristic indentation depth, hc = 8–10 μm, beyond which the mechanical response of the carbonate-rich shale is homogeneous and independent of its complex heterogeneous microstructure. Moreover, exploiting the results of a large number of indentation tests, we demonstrate that the indentation modulus M of the shale increases as a power-law of hardness H, and its creep modulus C increases linearly with H. We also compute the fracture toughness Kc from the indentation data by assuming a perfectly plastic behavior of the sample. Our results are in good agreement with independent measurements of Kc determined by microscratch tests. Finally, further tests on quartz- and clay-rich samples of the Longmaxi shale suggest further variations in the samples’ mechanical properties depending on their burial conditions and the mechanical properties of their dominant mineral phases. 2021-10-25T19:02:35Z 2021-10-25T19:02:35Z 2020-12 2020-08 2021-10-22T15:11:29Z Article http://purl.org/eprint/type/JournalArticle 1674-7755 https://hdl.handle.net/1721.1/133114 Jianting Du, Andrew J. Whittle, Liming Hu, Thibaut Divoux, Jay N. Meegoda, Characterization of meso-scale mechanical properties of Longmaxi shale using grid microindentation experiments, Journal of Rock Mechanics and Geotechnical Engineering, Volume 13, Issue 3, 2021 en 10.1016/j.jrmge.2020.09.009 Journal of Rock Mechanics and Geotechnical Engineering Creative Commons Attribution-NonCommercial-NoDerivs License http://creativecommons.org/licenses/by-nc-nd/4.0/ application/pdf Elsevier BV Elsevier |
| spellingShingle | Du, J Whittle, AJ Hu, L Divoux, T Meegoda, JN Characterization of meso-scale mechanical properties of Longmaxi shale using grid microindentation experiments |
| title | Characterization of meso-scale mechanical properties of Longmaxi shale using grid microindentation experiments |
| title_full | Characterization of meso-scale mechanical properties of Longmaxi shale using grid microindentation experiments |
| title_fullStr | Characterization of meso-scale mechanical properties of Longmaxi shale using grid microindentation experiments |
| title_full_unstemmed | Characterization of meso-scale mechanical properties of Longmaxi shale using grid microindentation experiments |
| title_short | Characterization of meso-scale mechanical properties of Longmaxi shale using grid microindentation experiments |
| title_sort | characterization of meso scale mechanical properties of longmaxi shale using grid microindentation experiments |
| url | https://hdl.handle.net/1721.1/133114 |
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