VaultDoorGeological carbon sequestration involves the separation and capture of carbon dioxide (CO2) at the point of emissions followed by storage in deep underground geologic formations. This is also referred to as carbon (or CO2) capture and storage (CCS).

On this page, you will learn about the two ways to sequester CO2 in geological media: (1)


You will also learn about

suitable geological formations
concerns about geological sequestration


Physical mechanisms usually involve trapping CO2 within a cavity in the rock underground. These cavities are either large man-made cavities, such as caverns and mines or the pore space present within rock formations such as the structural traps in depleted oil and gas reservoirs and in aquifers.

Enhanced oil recovery

CO2 injection into oil and gas reservoirs is sometimes used to help push out the product and extend the amount of oil and gas that can be recovered from the site. This is called enhanced oil recovery. The United States is the world leader in enhanced oil recovery technology, using about 32 million tons of CO2 per year for this purpose. (2) In this way, there is an economic benefit to CO2 capture and storage for the oil and gas industry.


Chemical mechanisms of trapping CO2 involve transforming the CO2 or binding it chemically to another substance in the ground. This can be done in the following ways:

dissolving CO2 in underground water or reservoir oil
decomposing CO2 into its ionic components
locking CO2 into a stable mineral precipitate
adsorption trapping