Carbon dioxide sequestration: Modeling the diffusive and convective transport under a CO2 cap
Type
Conference PaperAuthors
Allen, RebeccaSun, Shuyu

KAUST Department
Computational Transport Phenomena LabEarth Science and Engineering Program
Environmental Science and Engineering Program
Physical Science and Engineering (PSE) Division
Date
2013-04-04Online Publication Date
2013-04-04Print Publication Date
2012Permanent link to this record
http://hdl.handle.net/10754/564511
Metadata
Show full item recordAbstract
A rise in carbon dioxide levels from industrial emissions is contributing to the greenhouse effect and global warming. CO2 sequestration in saline aquifers is a strategy to reduce atmospheric CO2 levels. Scientists and researchers rely on numerical simulators to predict CO2 storage by modeling the fluid transport behaviour. Studies have shown that after CO2 is injected into a saline aquifer, undissolved CO2 rises due to buoyant forces and will spread laterally away from the injection site under an area of low permeability. CO2 from this ‘capped' region diffuses into the fluid underlying it, and the resulting CO2-fluid mixture increases in density. This increase in density leads to gravity-driven convection. Accordingly, diffusive-convective transport is important to model since it predicts an enhanced storage capacity of the saline aquifer. This work incorporates the diffusive and convective transport processes into the transport modeling equation, and uses a self-generated code. Discretization of the domain is done with a cell-centered finite difference method. Cases are set up using similar parameters from published literature in order to compare results. Enhanced storage capacity is predicted in this work, similar to work done by others. A difference in the onset of convective transport between this work and published results is noticed and discussed in this paper. A sensitivity analysis is performed on the density model used in this work, and on the diffusivity value assumed. The analysis shows that the density model and diffusivity value is a key component on simulation results. Also, perturbations are added to porosity and permeability in order to see the effect of perturbations on the onset of convection, and results agree with similar findings by others. This work provides a basis for studying other cases, such as the impact of heterogeneity on the diffusion-convective transport. An extension of this work may involve the use of an equation of state to predict CO2 solubility at thermodynamic conditions, and studying the impact of salinity on CO2 solubility.Citation
Allen, R., & Sun, S. (2012). Carbon Dioxide Sequestration: Modeling the Diffusive and Convective Transport under a CO2 Cap. SPE Saudi Arabia Section Technical Symposium and Exhibition. doi:10.2118/160881-msPublisher
Society of Petroleum Engineers (SPE)Conference/Event name
SPE Saudi Arabia Section Technical Symposium and Exhibition 2012ISBN
9781632667113ae974a485f413a2113503eed53cd6c53
10.2118/160881-ms