Atmospheric concentrations of CO2, a major greenhouse gas, have risen primarily as a consequence of fossil fuel combustion for energy production. The developed world has committed to reduce by 2012 the release into the atmosphere of anthropogenic CO2 at levels on average lower by 5.2% than those of 1990. Mitigation of human-induced climate change involves basically three approaches. The first approach is to increase the efficiency of primary energy conversion and end use. The second approach is to substitute lower-carbon or carbon-free energy sources for the current sources. The third approach is carbon sequestration. Any viable system for sequestering carbon must be safe, environmentally benign, effective, economical and acceptable to the public. Sequestration of CO2 in geological media is likely to provide the first large-scale opportunity for concentrated sequestration of CO2, being immediately applicable as a result of the experience already gained in oil and gas production, and storage of natural gas. Given their inherent advantages, such as availability, competitive cost, and ease of transport and storage, fossil fuels will remain a major component of world’s energy supply in the foreseeable future. Fossil fuels are serendipitously linked with sedimentary basins in which CO2 can be sequestered1. CO2 can be sequestered in structural or stratigraphic traps, similarly to hydrocarbons trapped in natural reservoirs. Depleted gas reservoirs are primary candidates as geological traps for CO2. Carbon dioxide can be trapped by dissolution in oil or in deep brines. Solubility trapping in oil still requires a geological trap (the oil reservoir). The technology is commercially proven and applied in enhanced oil recovery operations. Up to 30 % of CO2 injected in deep saline aquifers dissolves over time in the formation water2. Injection and dissolution of CO2 in regional-scale flow systems leads to hydrodynamic trapping beneath competent, regional-scale sealing aquitards3. A considerable increase in permanently sequestered CO2 by injection in deep aquifers would be achieved through mineral trapping3. Preferential adsorption of gaseous CO2 into the coal matrix and methane release leads to adsorption trapping in coal beds4. Injection of CO2 into deep uneconomic coal beds has the added advantage that it releases methane that can be produced in enhanced coalbed methane recovery4. Cavity trapping refers to CO2 injection in mined caverns in salt beds and domes, similarly to the storage of natural gas. Although salt caverns theoretically have a large storage capacity, the associated costs are too high and the environmental problems related to brine disposal are significant. The selection of the method, strata and site for CO2 sequestration in geological media depends on a number of specific criteria being met. These criteria are scale dependent, some applying at the basin scale, other being site specific. The basin-scale criteria5 relate to: 1) tectonic setting, b) hydrodynamic and geothermal regimes, c) hydrocarbon potential and basin maturity; d) surface infrastructure; and e) socio-political conditions in the jurisdiction covering the basin. The sitespecific criteria fall into several categories: 1) surface; 2) in-situ conditions; 3) storage capacity; 4) injectivity and flow dynamics; and 5) sequestration efficiency (confinement safety). The surface infrastructure for CO2 separation, capture, transport and injection into the ground,
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