Adsorption and strain: The CO2-induced swelling of coal

Matthieu Vandamme (1) , Laurent Brochard (2) , Brice Lecampion (3) , Olivier Coussy (4)

1 multi-échelle - Modélisation et expérimentation multi-échelle pour les solides hétérogènes
2 msa - Matériaux et Structures Architecturés
3 Schlumberger Carbon Services
4 navier umr 8205 - Laboratoire Navier

Enhanced coal bed methane recovery (ECBM) consists in injecting carbon dioxide in coal bed methane reservoirs in order to facilitate the recovery of the methane. The injected carbon dioxide gets adsorbed at the surface of the coal pores, which causes the coal to swell. This swelling in confined conditions leads to a closure of the coal reservoir cleat system, which hinders further injection. In this work we provide a comprehensive framework to calculate the macroscopic strains induced by adsorption in a porous medium from the molecular level. Using a thermodynamic approach we extend the realm of poromechanics to surface energy and surface stress. We then focus on how the surface stress is modified by adsorption and on how to estimate adsorption behavior with molecular simulations. The developed framework is here applied to the specific case of the swelling of CO2-injected coal, although it is relevant to any problem in which adsorption in a porous medium causes strains.

Mots clés: Porous material; Constitutive behavior; Geological material; Adsorption; Molecular simulations

Domaines: Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]

Matthieu Vandamme, Laurent Brochard, Brice Lecampion, Olivier Coussy. Adsorption and strain: The CO2-induced swelling of coal. Journal of the Mechanics and Physics of Solids, 2010, 58 (10), pp.1489-1505. ⟨10.1016/j.jmps.2010.07.014⟩. ⟨hal-00542308⟩