A molecular informed poroelastic model for organic-rich, naturally occurring porous geocomposites

Disorder-induced stiffness degradation of highly disordered porous materials

“…Indeed, based primarily upon Eshelby's inclusion problem ( Eshelby, 1957 ) and the assumption of scale separation, the consideration of composite materials as an assembly of (interacting) monodisperse spherical inclusions exhibiting characteristic morphologies from matrix-inclusion ( Mori and Tanaka, 1973 ) to poly-crystals and granular ( Hill, 1965 ), fails to address explicitly mesoscale texture effects. Such texture effects originate often from the material manufacturing process (such as inhomogeneous precipitation in cement hydration Del Gado et al, 2014;Ioannidou et al, 2016;Masoero et al, 2012 ) or material maturation processes (such as biologically mediated inorganicorganic tissue growth ( Hellmich and Ulm, 2002 ) or the diagenesis of organic-rich, naturally occurring porous geocomposites ( Monfared and Ulm, 2016 )).…”

Nanomechanics of organic-rich shales: the role of thermal maturity and organic matter content on texture

“…Since kerogen density is not an input in our analysis, it hardly changes the model predictions (clay indentation modulus, hardness and predicted kerogen volume fraction). However, it changes the calculated volume fraction of kerogen at level I obtained from TOC measurements (equations [15][16]. Based on our analysis, a 10% increase in kerogen density results in a 6-9% reduction in calculated kerogen volume fraction at level I for both mature and immature samples.…”

“…The hypothesis consists of attributing the first-order contribution of organic maturity on composite response of immature and mature systems to a texture effect, by considering a matrix-inclusion morphology for immature systems and a polycrystal/granular morphology for mature systems -while recognizing that the reality of such highly heterogeneous material systems like source rocks is somewhat situated in between. The successful implementation of these models to interpret nanoindentation results from various organic-rich shales allows us to identify unique mechanical properties of clay that are insensitive to maturity and TOC of the organic matter in shale formation; as well as consistent with molecular simulation results of illite [13] and back-analysis results from acoustic measurements [15]. The information gathered at these fundamental scales are pivotal for designing and validating predictive upscaling models.…”

A methodology to calibrate and to validate effective solid potentials of heterogeneous porous media from computed tomography scans and laboratory-measured nanoindentation data

“…Maturity refers to the process of physical, chemical and structural evolution of organic content with geologic time due to exposure to high-pressure and high-temperature environments [47,53]. Such evolution results in microtextural changes that impact the effective poroelastic behavior of organic-rich shales as a geocomposite [41]. Utilizing an informed Otsu's method, Hubler et al [28] segmented the CT scans by grouping all their constituents into four phases-three solid phases (clay, inclusions, organics) and a pore phase.…”

“…To fully capture this behavior, five elastic constants are needed. To this end, the values obtained through the inversion of ultrasonic pulse velocity data through the multi-scale molecular informed micromechanics model of Monfared and Ulm [41] ;…”