6. Geological storage of CO2

6.1 Selecting a storage site

Geological underground storage represents the main option available for storing large quantities of CO ₂ over the very long term. In fact, there are numerous natural underground CO ₂ deposits all over the world, which have performed such a storage function for millions of years. The general principle implemented for such storage is to make use of the fact that sedimentary rocks are generally porous. Sandstones, which consist of agglomerated sand particles, are a good example. The pore space contained in these rocks is most often occupied by salt water (saline aquifer). To store CO ₂ , we inject it into such a rock through...