Nanomechanics of organic-rich shales: the role of thermal maturity and organic matter content on texture
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Nano-MechanicsofOrganicRichShales-TheRoleofThermalMaturityand..._Final.pdf
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Author(s)
Abedi, Sara
Slim, Mirna I.
Ulm, Franz-Josef
Date Issued
June 2016
Journal
Acta Geotechnica
Publisher
Springer-Verlag
Citation
Abedi, Sara et al. “Nanomechanics of Organic-Rich Shales: The Role of Thermal Maturity and Organic Matter Content on Texture.” Acta Geotechnica 11, 4 (June 2016): 775–787 © 2016 Springer-Verlag Berlin Heidelberg
Version
Author's final manuscript
Abstract
Despite the importance of organic-rich shales, microstructural characterization and theoretical modeling of these rocks are limited due to their highly heterogeneous microstructure, complex chemistry, and multiscale mechanical properties. One of the sources of complexity in organic-rich shales is the intricate interplay between microtextural evolution and kerogen maturity. In this study, a suite of experimental and theoretical microporomechanics methods are developed to associate the mechanical properties of organic-rich shales both to their maturity level and to the organic content at micrometer and sub-micrometer length scales. Recent results from chemomechanical characterization experiments involving grid nanoindentation and energy-dispersive X-ray spectroscopy (EDX) are used in new micromechanical models to isolate the effects of maturity levels and organic content from the inorganic solids. These models enable attribution of the role of organic maturity to the texture of the indented material, with immature systems exhibiting a matrix-inclusion morphology, while mature systems exhibit a polycrystal morphology. Application of these models to the interpretation of nanoindentation results on organic-rich shales allows us to identify unique clay mechanical properties that are consistent with molecular simulation results for illite and independent of the maturity of shale formation and total organic content. The results of this investigation contribute to the design of a multiscale model of the fundamental building blocks of organic-rich shales, which can be used for the design and validation of multiscale predictive poromechanics models. Keywords: Maturity; Microporomechanics; Nanoindentation; Organic content; Organic-rich shale; Texture
MIT Department
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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DOI of Published Version
https://doi.org/10.1007/S11440-016-0476-2
