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Title: Effects of CO 2 on mechanical variability and constitutive behavior of the Lower Tuscaloosa formation, Cranfield Injection Site, USA

We characterize geomechanical constitutive behavior of reservoir sandstones at conditions simulating the “Cranfield” Southeast Regional Carbon Sequestration Partnership injection program. From two cores of Lower Tuscaloosa Formation, three sandstone lithofacies were identified for mechanical testing based on permeability and lithology. These include: chlorite-cemented conglomeratic sandstone (Facies A); quartz-cemented fine sandstone (Facies B); and quartz- and calcite-cemented very fine sandstone (Facies C). We performed a suite of compression tests for each lithofacies at 100 °C and pore pressure of 30 MPa, including hydrostatic compression and triaxial tests at several confining pressures. Plugs were saturated with supercritical CO 2-saturated brine. Chemical environment affected the mechanical response of all three lithofacies, which experience initial plastic yielding at stresses far below estimated in situ stress. Measured elastic moduli degradation defines a secondary yield surface coinciding with in situ stress for Facies B and C. Facies A shows measurable volumetric creep strain and a failure envelope below estimates of in situ stress, linked to damage of chlorite cements by acidic pore solutions. Furthermore, the substantial weakening of a particular lithofacies by CO 2 demonstrates a possible chemical-mechanical coupling during injection at Cranfield with implications for CO 2 injection, reservoir permeability stimulation, and enhanced oil recovery.
 [1] ;  [2] ;  [2] ;  [3]
  1. New Mexico Tech, Socorro, NM (United States)
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  3. Texas Bureau of Economic Geology, Austin, TX (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 1750-5836; PII: S1750583616304947
Grant/Contract Number:
Published Article
Journal Name:
International Journal of Greenhouse Gas Control
Additional Journal Information:
Journal Volume: 53; Journal Issue: C; Journal ID: ISSN 1750-5836
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
54 ENVIRONMENTAL SCIENCES; chemo-mechanical coupling; Lower Tuscaloosa formation; Cranfield injection test; experimental rock mechanics; elastic moduli degradation; chlorite cement
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1338303