Modelling by homogenization of the long term rock dissolution and geomechanical effects

The geological storage of CO2 coming from large industrial facilities has been studied in detail for the last several years as a solution against the greenhouse effect and climate change in a number of countries. It is considered as a complementary solution together with the research for the non pollutant or/and renewable energy sources. One of the available options is the injection of the supercritical CO2 in the saline aquifers. The idea of geological storage resides in various mechanisms of trapping coming into play progressively over time. In the short term the migration of CO2 is principally blocked by the impervious rock lying on the top of the aquifer. As time goes on, other mechanisms appear, in particular of geochemical nature, like the dissolution of CO2 in pore water, and finally the chemical reactions resulting in dissolution and /or precipitation of rock minerals. These reactions can generate important and irreversible modifications of the hydrodynamical as well as geomechanical properties of the reservoir.