Trapping mechanisms for carbon geosequestration
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Trapping mechanisms for carbon geosequestration prevent carbon dioxide stored in geological structures from leaking into the atmosphere. As a means to lower greenhouse gas emissions, carbon dioxide from carbon sequestration, especially in terms of carbon capture and storage, is able to be directed from power plants and other sources of greenhouse gas emissions, with carbon dioxide emissions being pumped into subterranean storage facilities. However, there is still the risk of the carbon dioxide leaking from the underground storage facilities. To address this, several trapping mechanisms have been proposed and researched.[1]
This is most likely the main solution for preventing leaks. Impermeable (or low permeability) rocks such as caprock or similar material blocks the gas flow. Mudrocks, anhydrite, halite, or tight carbonates are materials that can act as a barrier to the upward buoyant migration of carbon dioxide.[1][2]
Residual/capillary trapping
Higher capillary forces to buoyant forces cause carbon dioxide to appear as pore-scale bubbles in the formation. This is a process through which micrometer scale carbon dioxide bubbles are immobilized by capillary forces within the complex pore structure of the storage rock.[2]