One of the objectives of the Aquistore project – which has seen over 393 kilotonnes of CO2 injected 3.2 km underground into a deep saline formation – has been to track the growth of the CO2 plume over time. To date, this has been accomplished by surface-based 4D seismic imaging (4 time-lapse images have been produced since injection began) and PND logging in the observation well. 4D…