CO2 storage in caverns and mines

In addition to the “conventional” geological storage options (depleted hydrocarbon reservoirs, saline aquifers and unminable coal seams), it has been suggested that CO2 may also be stored in large man-made cavities such as caverns and mines. It is noted that salt caverns, along with depleted gas reservoirs and aquifers, have been used to store natural gas to meet seasonal cyclic or daily demand increase for several decades. Examples of natural gas storage in abandoned mines can also be found. The proven track record of salt caverns and abandoned mines or natural gas storage suggest that they may offer alternative solutions for geological storage of CO2, particularly where the conventional storage options (saline aquifers, depleted oil and gas reservoirs and deep unminable coal seams) are limited or not available near a point CO2 source. In order to reduce the transport distance and thus overall storage cost, geological storage sites should be located as close to the CO2 emissions points as possible.