3.2 Storage in depleted oil and gas fields

Depleted oil and gas reservoirs are good candidates for CO2 storage because their ability to trap fluids over millions of years has already been demonstrated. In addition, the geological structure and reservoir properties have usually been studied extensively. Injecting CO2 into such reservoirs can also be aided by the fact that some of the infrastructure is already in place. However, the integrity of existing abandoned wells will need to be demonstrated with the wells repaired, if necessary.

The pressure regime of depleted oil and gas fields is likely to be very different to that of saline formations and this could significantly affect the design of the transport and injection system.