We are collaborating on the development of acoustic techniques to detect leaks from subsea storage sites for CO2, mainly exploiting depleted hydrocarbon fields in the North Sea. A significant challenge for such sites is ensuring their integrity once in use, requiring demonstration that the CO2 remains within the facility.
In the event of a leak, detection and quantification is vital. CO2 entering the water column is expected to do so partly in gas phase.The gas component of such a leak can be efficiently detected remotely (>100 m) using active acoustic techniques (sonar), because gas bubbles are strong scatterers of sound. CO2 dissolves comparatively rapidly in water, so the plumes will not extend far into the water column, with a characteristic acoustic signature.
Whilst active methods are well suited to detecting CO2 leakage, they are not effective at quantification of leak rates. For this, passive acoustic methods provide a complementary alternative facilitating the estimation of gas fluxes at short ranges.