Dragan Grgic

THM modeling of the CO2 injection in coal: influence of Biot's coefficient and Langmuir's adsorption parameters

CO2 injection in coal can modify the petro-physical properties. Indeed, the coal matrix swelling reduces the porosity and the permeability of coal on the one hand. On the other hand, the increase in gas pressure induces the decrease in the effective stresses and therefore the increase in the spacing between the matrix blocks. We used a theoretical model for the variation of the Eulerian porosity which takes into account the adsorption process. This process is classically modeled with the Langmuir’s isotherm. After implementation in Code_Aster (EDF), we investigated through numerical simulations (1D and 2D axisymmetric) the influence of the Biot’s coefficient and the Langmuir’s adsorption parameters during CO2 injection in coal. This simulations showed that the increase in Langmuir’s parameters, as well as the increase in the Biot’s coefficient, promotes the reduction of the porosity when the gas pressure increases.

Influence du vieillissement et de l'eau sur le comportement mécanique des mines de fer abandonnées de Lorraine

ABSTRACT In order to better explain mining collapses that occur in Lorraine, a hydro-mechanical constitutive law is proposed for the iron ore after performing laboratory tests. This law takes account of the active physical phenomena during a short-term loading and its simulation is compared with experimental results. The ageing and mine flooding influence on iron ore mechanical behaviour is discussed. The iron ore ageing is of anthropogenic origin and its characteristics are shown.