Fracture and mechanical characteristics of CO2-saturated sandstone at extreme loading conditions

H. Z. Xing, G. Wu, S. Dehkhoda, P. G. Ranjith, Q. B. Zhang

Research output: Contribution to journalArticleResearchpeer-review

1 Citation (Scopus)

Abstract

Dynamic compression and Brazilian disc tests were performed on dry, water- and brine-saturated sandstone with and without scCO 2 (supercritical carbon dioxide) injection. Split Hopkinson pressure bar (SHPB) tests were conducted under different strain rates. The full-field deformation and fracturing process were investigated by the high-speed 3D digital image correlation (DIC) technique with a resolution of 256 × 256 pixels at 200,000 frames per second (fps). The presence of CO 2 attenuated the dynamic compressive strength for dry and water-saturated sandstone. The dry sandstone has a greater brittleness with the saturation of CO 2 , but there was an opposite trend for water-saturated sandstone saturated by CO 2 . The presence of CO 2 had less effect on the dynamic mechanical properties on the brine-saturated sandstone. The normalised stress threshold for crack initiation became lower for the dry and water treated specimen but was less effective in brine-saturated sandstone. The injection of CO 2 intensified the fracturing degree, branching and altered the crack initiation position under dynamic loading. The mechanism of CO 2 effect was studied from mineralogical structure alteration based on the observation by scanning electron microscope (SEM).

Original languageEnglish
Pages (from-to)132-141
Number of pages10
JournalInternational Journal of Rock Mechanics and Mining Sciences
Volume117
DOIs
Publication statusPublished - 1 May 2019

Keywords

  • CO saturation
  • Digital image correlation
  • dynamic fracture
  • Microstructure
  • Split Hopkinson pressure bar

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