Mechanisms for mechanical trapping of geologically sequestered carbon dioxide
Carbon dioxide (CO[subscript 2]) sequestration in subsurface reservoirs is important for limiting atmospheric CO[subscript 2] concentrations. However, a complete physical picture able to predict the structure developing within the porous medium is lacking. We investigate theoretically reactive trans...
| Principais autores: | , |
|---|---|
| Outros Autores: | |
| Formato: | Artigo |
| Idioma: | en_US |
| Publicado em: |
Royal Society
2015
|
| Acesso em linha: | http://hdl.handle.net/1721.1/93870 https://orcid.org/0000-0003-4006-7771 https://orcid.org/0000-0002-7997-0119 |
| Resumo: | Carbon dioxide (CO[subscript 2]) sequestration in subsurface reservoirs is important for limiting atmospheric CO[subscript 2] concentrations. However, a complete physical picture able to predict the structure developing within the porous medium is lacking. We investigate theoretically reactive transport in the long-time evolution of carbon in the brine–rock environment. As CO[subscript 2] is injected into a brine–rock environment, a carbonate-rich region is created amid brine. Within the carbonate-rich region minerals dissolve and migrate from regions of high-to-low concentration, along with other dissolved carbonate species. This causes mineral precipitation at the interface between the two regions. We argue that precipitation in a small layer reduces diffusivity, and eventually causes mechanical trapping of the CO[subscript 2]. Consequently, only a small fraction of the CO[subscript 2] is converted to solid mineral; the remainder either dissolves in water or is trapped in its original form. We also study the case of a pure CO[subscript 2] bubble surrounded by brine and suggest a mechanism that may lead to a carbonate-encrusted bubble owing to structural diffusion. |
|---|