Geological Storage as a Carbon Mitigation Option
Abstract
One of the most promising approaches for carbon mitigation involves essentially-zero-emission power plants based on carbon capture and storage (CCS) technology. The key to any CCS strategy is a suitable choice for large-scale storage of the captured CO2. While a variety of storage options are being studied, geological storage appears to be most viable. Injection of captured CO2 into deep geological formations leads to a fairly complex flow system involving multiple fluid phases, a range of potential geochemical reactions, and mass transfer across phase interfaces. General models of this system are computationally demanding, with the problem made more difficult by the large range of spatial scales involved as well as the importance of local features for both fluid flow and geochemical reactions. An especially important local feature involves leakage pathways, with one example being abandoned wells associated with the century-long legacy of oil and gas exploration and production. Such pathways also have large uncertainties associated with their properties. Therefore, inclusion of leakage in the storage analysis requires resolution of multiple scales and incorporation of large uncertainties. Furthermore, when implemented at full scale, geological storage will induce subsurface perturbations that extend across entire basins. Taken together, these requirements render standard numerical simulators ineffective due to their excessive computational demands. A series of physically-motivated simplifications to the governing equations can ultimately render the system solvable by analytical or semi-analytical methods. These solutions, while restrictive in their assumptions, allow for large-scale analysis of leakage in a probabilistic framework and can provide a basis for regulatory policies.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFM.U42A..01C
- Keywords:
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- 1622 Earth system modeling (1225);
- 1832 Groundwater transport;
- 1847 Modeling;
- 1849 Numerical approximations and analysis;
- 1859 Rocks: physical properties