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Numerical modelling of the hydro‐chemo‐mechanical behaviour of geomaterials in the context of CO 2 injection
Author(s) -
Vallin V.,
Pereira J.M.,
Fabbri A.,
Wong H.
Publication year - 2013
Publication title -
international journal for numerical and analytical methods in geomechanics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.419
H-Index - 91
eISSN - 1096-9853
pISSN - 0363-9061
DOI - 10.1002/nag.2192
Subject(s) - carbonation , caprock , porosity , dissolution , permeability (electromagnetism) , aquifer , geotechnical engineering , geomechanics , cement , materials science , context (archaeology) , petroleum engineering , geology , groundwater , composite material , engineering , chemistry , chemical engineering , biochemistry , membrane , paleontology
SUMMARY Safety assessment of geosequestration of CO 2 into deep saline aquifers requires a precise understanding of the study of hydro‐chemo‐mechanical couplings occurring in the rocks and the cement well. To this aim, a coupled chemo‐poromechanical model has been developed and implemented into a research code well‐suited to the resolution of fully coupled problems. This code is based on the finite volume methods. In a 1D axisymmetrical configuration, this study aims to simulate the chemo‐poromechanical behaviour of a system composed by the cement well and the caprock during CO 2 injection. Major chemical reactions of carbonation occurring into cement paste and rocks are considered in order to evaluate the consequences of the presence of CO 2 on the amount of dissolved matrix and precipitated calcium carbonates. The dissolution of the solid matrix is taken into account through the use of a chemical porosity. Matrix leaching and carbonation lead, as expected, to important variations of porosity, permeability and to alterations of transport properties and mechanical stiffness. These results justify the importance of considering a coupled analysis accounting for the main chemical reactions. It is worth noting that the modelling framework proposed in the present study could be extended to model the chemo‐poromechanical behaviour of the reservoir rock and the caprock when subjected to the presence of an acidic pore fluid (CO 2 ‐rich brine). Copyright © 2013 John Wiley & Sons, Ltd.