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Title: On sorption and swelling of CO 2 in clays

One well-studied technology is the geological storage of carbon dioxide (CO 2), and a number of demonstration projects around the world have proven its feasibility and challenges. Storage conformance and seal integrity are among the most important aspects, as they determine risk of leakage as well as limits for storage capacity and injectivity. By providing evidence for safe storage is critical for improving public acceptance. Most caprocks are composed of clays as dominant mineral type which can typically be illite, kaolinite, chlorite or smectite. A number of recent studies addressed the interaction between CO 2 and these different clays and it was shown that clay minerals adsorb considerable quantities of CO 2. For smectite this uptake can lead to volumetric expansion followed by the generation of swelling pressures. On the one hand CO 2 adsorption traps CO 2, on the other hand swelling pressures can potentially change local stress regimes and in unfavourable situations shear-type failure is assumed to occur. Moreover, for storage in a reservoir having high clay contents the CO 2 uptake can add to storage capacity which is widely underestimated so far. Smectite-rich seals in direct contact with a dry CO 2 plume at the interface tomore » the reservoir might dehydrate leading to dehydration cracks. Such dehydration cracks can provide pathways for CO 2 ingress and further accelerate dewatering and penetration of the seal by supercritical CO 2. At the same time, swelling may also lead to the closure of fractures or the reduction of fracture apertures, thereby improving seal integrity. Finally, the goal of this communication is to theoretically evaluate and discuss these scenarios in greater detail in terms of phenomenological mechanisms, but also in terms of potential risks or benefits for carbon storage.« less
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [5] ;  [1]
  1. Shell Global Solutions International, Rijswijk (Netherlands)
  2. RWTH Aachen Univ. (Germany)
  3. Stanford Univ., CA (United States)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  5. Univ. of Utrecht (Netherlands)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Geomechanics and Geophysics for Geo-Energy and Geo-Resources
Additional Journal Information:
Journal Volume: 2; Journal Issue: 2; Journal ID: ISSN 2363-8419
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
58 GEOSCIENCES; geologic carbon storage; CO2 sorption and wetting; clay swelling; shale mechanics
OSTI Identifier: