The Potential for Carbon Dioxide Sequestration in Subsurface Geological Formations

• Main Authors: Nomeli, Mohammad A., Riaz, Amir
• Format: Other/Unknown Material
• Language: English
• Published: Wiley 2015
• Subjects: Carbonic acid
• Online Access: http://dx.doi.org/10.1002/9781118991978.hces161; https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781118991978.hces161

Abstract Fossil fuels are projected to serve as the major source of energy worldwide in the decades to come. Emissions to the atmosphere of green house gases such as carbon dioxide (CO 2 ) produced by the consumption of energy derived from fossil fuels are now comparable to the natural carbon cycle. Such emissions are already beginning to exert an observable influence on climate change, perturbing natural climate stability. Carbon sequestration has been proposed to gradually reduce and eventually eliminate anthropogenic emissions of CO 2 into the atmosphere. The success of sequestration depends on the identification and manipulation of appropriate storage sites where CO 2 can be sequestrated over long periods of time. Deep saline aquifers are the preferred storage sites because of their potential for secure sequestration over long periods of time as well as their abundance and large capacity. The primary mechanism for long‐term sequestration in saline aquifers is solubility trapping associated with the dissolution of CO 2 into brine. The solution of saline water and dissolved CO 2 is negatively buoyant within the subsurface environment. The positively buoyant‐free CO 2 is thus trapped and loses its ability to escape from the aquifer. The key aspect of solubility trapping is gravitational convection associated with the unstable density stratification of dissolved CO 2 . The rate of mixing of free CO 2 with brine is enhanced significantly as a result of gravitational convection compared with the extremely slow process of diffusion limited mixing. The strength of convection depends on solubility, which is a function of temperature and pressure and brine salinity. Dissolution of CO 2 into brine leads further to the formation of carbonic acid that provides carbonate ions needed for the formation of mineral precipitates. This process of mineral trapping of CO 2 is considered to be the most permanent form of sequestration. The objective of this study is to provide a perspective on the progress made thus far toward the ...