Evolutions in the Elastic Constants of Ca-Montmorillonites with H2O/CO2 Mixture under Supercritical Carbon Dioxide Conditions

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• 作者：Wei N. Zhang ; Hai X. Hu ; Xiao C. LiZhi M. Fang
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：February 9, 2017
• 年：2017
• 卷：121
• 期：5
• 页码：2702-2710
• 全文大小：769K
• ISSN：1932-7455

文摘

Clay mineral plays a crucial role in determining permeability and affecting mechanical properties of caprock formations in geologic carbon sequestration (GCS) and enhanced oil recovery (EOR) engineering. In the corresponding environment, CO<sub>2sub>–H<sub>2sub>O intercalation not only causes swelling or shrinkage of clay mineral but also results in affecting mechanical properties of mineral. However, influence of quantitative CO<sub>2sub>/H<sub>2sub>O adsorption on mechanical properties of clay still remains unknown. This work investigated evolutions of elastic properties of Ca-MMT with variable CO<sub>2sub>–H<sub>2sub>O component using molecular dynamic method. Elastic coefficients C<sub>ijsub>, bulk modulus K, shear modulus G, Young’s modulus E<sub>iisub>, and Poisson’s ratio E<sub>ijsub> were correlated to qualified adsorption of CO<sub>2sub>–H<sub>2sub>O mixture. We obtained the following conclusions: (1) in-plane elastic constants, bulk modulus, shear modulus, and Young’s modulus E<sub>33sub> had distinct correlation with the profile of d<sub>001sub> spacing as a function of H<sub>2sub>O content at fixed CO<sub>2sub> content; (2) no distinct evolution profile was found in Poisson’s ratio as a function of CO<sub>2sub> or H<sub>2sub>O content; (3) we revealed that the mixture of CO<sub>2sub>/H<sub>2sub>O caused decrease in strength of clay mineral; and (4) varying ranges of all elastic constant were summarized for clay-CO<sub>2sub>–H<sub>2sub>O considered in this work.