Assessing the mechanical microstructure of shale by nanoindentation : the link between mineral composition and mechanical properties
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2009
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| Online Access: | http://hdl.handle.net/1721.1/47731 |
| _version_ | 1826216353981267968 |
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| author | Bobko, Christopher Philip, 1981- |
| author2 | Franz-Josef Ulm. |
| author_facet | Franz-Josef Ulm. Bobko, Christopher Philip, 1981- |
| author_sort | Bobko, Christopher Philip, 1981- |
| collection | MIT |
| description | Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008. |
| first_indexed | 2024-09-23T16:45:59Z |
| format | Thesis |
| id | mit-1721.1/47731 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T16:45:59Z |
| publishDate | 2009 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/477312019-04-12T10:23:50Z Assessing the mechanical microstructure of shale by nanoindentation : the link between mineral composition and mechanical properties Bobko, Christopher Philip, 1981- Franz-Josef Ulm. Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering. Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering. Civil and Environmental Engineering. Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008. Includes bibliographical references (leaves 335-351). Shale is a multi-phase, multi-scale sedimentary rock that makes up 75% of the earth's sedimentary basins and is especially critical in petroleum engineering applications. At macroscopic scales, shales possess a diverse set of possible compositions, resulting in a diverse set of mechanical properties. This thesis assesses microstructure and material invariant properties of shale as the link between engineering performance and composition. A comprehensive experimental microporomechanics approach, employing advanced experimental and analytical nanoindentation techniques, provides the basis for assessment of microstructure and material invariant properties. Nanoindentation experiments and analysis tools are designed to probe and infer the elastic and strength properties of the porous clay composite in shale. The results of this investigation show that properties of the porous clay composite scale with the clay packing density in the material, but otherwise do not depend on mineral composition. These scaling relationships are representative of a granular composite of spherical particles, and lead to identification of intrinsically anisotropic material invariant elastic properties and intrinsically isotropic material invariant hardness properties. The material invariant hardness represents a combination of cohesive and frictional behavior that is seen to scale with the average clay packing density in the sample. Nanoindentation results also provide evidence of packing density distributions that are analogous to pore size distributions. (cont.) These observations are combined to define a model of the elementary building block of shale. Exploring the physical origin of this building block suggests that it represents an agglomerated polycrystal group of individual clay minerals. Particles in the porous clay composite exhibit fractal packings, which suggest a quantitative link between contemporary theories about the origin of friction and the experimental scaling of friction in shale. The new understanding provided by this thesis represents a leap forward for predictive models of shale behavior. The model of the elementary building block can be used as a basis for micromechanical homogenization models which predict poroelastic properties and strength behavior of shale at the lab-bench scale based on only two volume fraction parameters. The success of these models validates the elementary building block model and illustrates its engineering significance. by Christoper P. Bobko. Ph.D. 2009-10-01T15:36:01Z 2009-10-01T15:36:01Z 2008 2008 Thesis http://hdl.handle.net/1721.1/47731 428430530 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 2 v. (351 leaves) application/pdf Massachusetts Institute of Technology |
| spellingShingle | Civil and Environmental Engineering. Bobko, Christopher Philip, 1981- Assessing the mechanical microstructure of shale by nanoindentation : the link between mineral composition and mechanical properties |
| title | Assessing the mechanical microstructure of shale by nanoindentation : the link between mineral composition and mechanical properties |
| title_full | Assessing the mechanical microstructure of shale by nanoindentation : the link between mineral composition and mechanical properties |
| title_fullStr | Assessing the mechanical microstructure of shale by nanoindentation : the link between mineral composition and mechanical properties |
| title_full_unstemmed | Assessing the mechanical microstructure of shale by nanoindentation : the link between mineral composition and mechanical properties |
| title_short | Assessing the mechanical microstructure of shale by nanoindentation : the link between mineral composition and mechanical properties |
| title_sort | assessing the mechanical microstructure of shale by nanoindentation the link between mineral composition and mechanical properties |
| topic | Civil and Environmental Engineering. |
| url | http://hdl.handle.net/1721.1/47731 |
| work_keys_str_mv | AT bobkochristopherphilip1981 assessingthemechanicalmicrostructureofshalebynanoindentationthelinkbetweenmineralcompositionandmechanicalproperties |