CO2 SequestrationCarbon Dioxide Mitigation:
Geologic Carbon Dioxide Sequestration

Fossil fuels will continue to dominate the world’s energy supply for several decades. It will be necessary to find ways to capture and sequester a significant amount of the carbon dioxide emissions from these fuels in the near term in order to seriously address global warming related to these emissions. Geologic sequestration in underground reservoir is one technically viable method to do this.

Geologic sequestration of carbon dioxide is generally divided into two categories:

  • Injection into hydrocarbon reservoirs as a means of recovering additional hydrocarbons
  • Injection into deep saline aquifers simply for long term storage

Injection into hydrocarbon reservoirs can include the following cases:

  • Injection into depleted natural gas reservoirs. These reservoirs have the advantage of having demonstrated that the gas will remain in place over geologic time because they had stored natural gas over geologic time.
  • Injection into coal seams. CO2 has a natural affinity for adsorption within the coal matrix and has the added benefit of displacing methane which can then be used as cleaner burning hydrocarbon.
  • Injection into partially depleted oil reservoirs to increase the recovery of oil. This injected CO2 displaces the oil to the producing wells. Some of the CO2 is produced with the oil but is separated and re-injected into the oil field. Ultimately the oil field will be abandoned with the CO2 remaining underground.

Injection into deep saline aquifers is a viable option for sequestration because at the temperature and pressures desired for storage the CO2 is in a dense (almost liquid) form and there is a very large geographic distribution of accessible formations. This allows the injection of CO2 near the source of capture reducing the need for expensive transmission pipelines.

Bryant, Steven; 2007, Geologic CO2 Storage—Can the Oil and Gas Industry Help Save the Planet?, Society of Petroleum Engineers Journal of Petroleum Technology, September 2007, SPE Paper #103474