CO2 Sequestration: Results, challenges and visions
Event details
| Date | 24.05.2011 |
| Hour | 09:15 |
| Speaker | Philipp Blum, Assistant Professor, Karlsruhe Institute of Technology, D |
| Location |
ELA 1
|
| Category | Conferences - Seminars |
Various trapping mechanisms exist to perform a long-term storage of CO2 in deep
geological formations such as fractured saline aquifers. Hence, the understanding of these small- and large-scale processes such as diffusion and regional multi-phase flow in fractured rocks is crucial for a secure and lasting storage of CO2. Using laboratory through-diffusion experiments it was possible to determine effective diffusion coefficients for sandstone samples ranging between 1.8 ~ 10-7 and 5.6 ~ 10-6 cm2/s mainly depending on porosity. Thus, it could be demonstrated that the Archiefs Law is also applicable for diffusion of free aqueous CO2 in sandstones. Furthermore, geochemical changes in pore water chemistry and geometry in reservoir rocks due to CO2 injection was studied using two different flow through autoclave systems. Total reflection X-ray fluorescence (TXRF), inductively coupled plasma optical emission spectrometry (ICP-OES) and isotope ratio mass spectrometer (CF-IRMS) were used for the fluid analysis. Laboratory studies using the Bentheimer Sandstone, which is mainly composed of quartz and feldspar, showed significant dissolution of feldspar, whereas quartz dissolution was less pronounced due to slow reaction kinetics. Additional laboratory and field studies with stable isotopes (ƒÂ13C and ƒÂ18O) indicate that ƒÂ13C is suitable monitoring parameter for the observation of critical geochemical
changes. The field studies were performed at the Ketzin site, the first on-shore CO2 injection pilot test site in Europe. The preliminary results showed that around 70% of the dissolved inorganic carbon (DIC) is from the CO2 injection and the remaining 30% orignates from the dissolution of carbonate minerals. Finally, a methodology for the upscaling of hydro-mechanical processes in fractured rocks is presented. The results of this large-scale study clearly demonstrate the importance of the spatial properties of discrete fracture networks (DFN) and the mechanical properties of reservoir rocks. In addition to the diverse results, research challenges are highlighted and interdisciplinary, collaborative, short- and long-term visions of the research group are provided.
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Practical information
- General public
- Free
Contact
- Christina Treier