CO2 moves upwards to the top seal. Over time the CO2 dissolves into the formation water. This makes it denser and it moves downwards.
Carbon dioxide can be injected into oil reservoirs, making the oil easier to produce. Some of the carbon dioxide remains trapped in the rocks.
Carbon dioxide can be reacted with minerals to form stable carbonates. The mineral needs to be crushed and research is underway to increase the rate of reaction.
CO2 can be stored in mineral residues such as red muds produced by alumina refineries.
Sedimentary basins offer the best prospect for geological storage of carbon dioxide.
As more information about a potential storage site is obtained, uncertainty about the volume of carbon dioxide that can be stored is reduced.
As the carbon dioxide moves through the storage rock, the tail of the plume becomes less dense. Bubbles of carbon dioxide can be snapped off by surrounding formation water and remain trapped in the pore space.
Australia has many sedimentary basins suitable for storing carbon dioxide.
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