@article {323,
	title = {Nanochemo-mechanical signature of organic-rich shales: a coupled indentation{\textendash}EDX analysis},
	journal = {Acta Geotechnica},
	volume = {11},
	year = {2016},
	month = {Jun-2016},
	pages = {559 - 572},
	abstract = {<p>The organic\&ndash;inorganic nature of organic-rich source rocks poses several challenges for the development of functional relations that link mechanical properties with geochemical composition. With this focus in mind, we herein propose a method that enables chemo-mechanical characterization of this highly heterogeneous source rock at the micron and submicron length scale through a statistical analysis of a large array of energy-dispersive X-ray spectroscopy (EDX) data coupled with nanoindentation data. The ability to include elemental composition to the indentation probe via EDX is shown to provide a means to identify pure material phases, mixture phases, and interfaces between different phases. Employed over a large array, the statistical clustering of this set of chemo-mechanical data provides access to the properties of the fundamental building blocks of clay-dominated organic-rich source rocks. The versatility of the approach is illustrated through the application to a large number of source rocks of different origin, chemical composition, and organic content. We find that the identified properties exhibit a unique scaling relation between stiffness and hardness. This suggests that organic-rich shale properties can be reduced to their elementary constituents, with several implications for the development of predictive functional relations between chemical composition and mechanical properties of organic-rich source rocks such as the intimate interplay between clay-packing, organic maturity, and mechanical properties of porous clay/organic phase.</p>
},
	issn = {1861-1125},
	doi = {10.1007/s11440-015-0426-4},
	author = {Abedi, Sara and Slim, Mirna and Hofmann, Ronny and Bryndzia, Taras and Franz-Josef Ulm}
}
@article {322,
	title = {Nanomechanics of organic-rich shales: the role of thermal maturity and organic matter content on texture},
	journal = {Acta Geotechnica},
	volume = {11},
	year = {2016},
	month = {Aug-2016},
	pages = {775 - 787},
	abstract = {<p>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.</p>
},
	issn = {1861-1125},
	doi = {10.1007/s11440-016-0476-2},
	author = {Abedi, Sara and Slim, Mirna and Franz-Josef Ulm}
}
