30. How do you know CO2 storage is safe?

Twelve years of research into the WMP has illustrated that CO2 storage is safe. The CO2 has been extensively monitored in the oilfields using different technologies, revealing to researchers where the CO2 is in the reservoir and how it has moved. In addition, well water and soils have been sampled across various locations above the injection site, and there has been no evidence of CO2 moving into the groundwater or the topsoil.

At the Weyburn and Midale oilfields, the CO2 has been injected to a depth of 1.5 kilometres, the equivalent of 15 football (or soccer) fields stood end-on-end. In addition to this depth, there are several thick layers of impermeable rock above the injected CO2 to stop it from coming back to the surface. It is also important to remember that the CO2 is not being injected into a blank space or body of water below the surface, but rather into rock formations that hold the CO2 in billions of pores that are typically the size of a grain of sand, or smaller. Movement of CO2 within such a formation is usually slow and can be monitored.