Interplay of Montmorillonite–H₂O–scCO₂ System between Mechanical Behavior and Adsorption: Molecular Dynamics

Abstract

Montmorillonite (MMT) constitutes most of fine-grained sedimentary rock, such as shale, mudstone, and siltstone. It is also applied in underground storage of carbon dioxide, petroleum drilling engineering, and material engineering. Although adsorption and mechanical behavior in MMT−H 2 O−CO 2 is widely studied, little is known about interplay between them. In this work, we have investigated the interplay between mechanical behavior and adsorption in MMT with different proportion of H 2 O and CO 2 content under super critical condition by molecular dynamic (MD) method. With respect to the calculated results, adsorption of H 2 O and CO 2 can diminish stiffness of MMT. Meanwhile, diffusion of H 2 O and CO 2 weakens because of stronger constrains deriving from geometry structure and hydrogen bond as the system undergoing compression test. Moreover, motion of H 2 O is restrained by CO 2 molecules as self-diffusion coefficient decrease with the increase of CO 2 . Hydrated MMT is more sensitive to deformation vertical to clay sheet which is confirmed by comparing changing tend of potential energy and stress. Process of adsorption can yield the stiffness of MMT structures while compression loading can slow down diffusion motions of adsobates. This impact we have revealed here is meaningful to understand mechanical properties of swelling MMT.

Self-diffusivity, M–S and Fick diffusivity of CO2 in Na-clay: The influences of concentration and temperature

“…With the current high-performance computational resources, molecular simulations have become powerful tools for understanding the molecular-scale structural 18, 19 , thermodynamic 20 , mechanical 21 and dynamic 22–25 properties of clay. Grand-canonical Monte Carlo (GCMC) method was used to examine the adsorption of CO 2 with H 2 O 23 , CH 4 26–28 and organic molecules 25, 29 in clay.…”

A modified true triaxial apparatus for measuring mechanical properties of sandstone coupled with CO2‐H2O biphase fluid

“…Montmorillonite (MMT) interacting with CO 2 can result in changes of basal spacing, which has been verified by experimental method . Zhang et al . have investigated the interplay between mechanical behavior and adsorption in MMT with different proportions of H 2 O and CO 2 content under supercritical conditions by molecular dynamic (MD) method.…”

“…Zhang et al 36 have investigated the interplay between mechanical behavior and adsorption in MMT with different proportions of H 2 O and CO 2 content under supercritical conditions by molecular dynamic (MD) method. With respect to the calculated results, adsorption of H 2 O and CO 2 can diminish stiffness of MMT.…”

The impact of different clay minerals on the anisotropy of clay matrix in shale

“…; Zhang et al . ; Zheng and Zaoui ), using molecular dynamics (MD) simulations with the Clay force field (CLAYFF). CLAYFF (Cygan, Liang and Kalinichev ) was designed to simulate hydrated or multicomponent minerals and their interfaces with aqueous solutions.…”

“…Many additional estimates of elastic stiffness tensors for various layered silicates have also been published (e.g. Mazo et al 2008;Ebrahimi, Pellenq and Whittle 2012;Teich-McGoldrick, Greathouse and Cygan 2012;Carrier et al 2014;Hantal et al 2014;Zhang et al 2015;Zheng and Zaoui 2018), using molecular dynamics (MD) simulations with the Clay force field (CLAYFF). CLAYFF (Cygan, Liang and Kalinichev 2004) was designed to simulate hydrated or multicomponent minerals and their interfaces with aqueous solutions.…”