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Field Well Integrity Assessment Onshore Australia

17 shut in or suspended wells in a depleted field onshore Australia were identified as potential candidates for conversion to CO2 injection or monitoring wells. The wells were drilled between 1966 and 2006, and have a range of architectures and technical issues. Zenith Energy Australia was engaged to perform a repurposing assessment to screen and rank the wells, and identify preferred candidates. This forms part of the field assessment for conversion of to carbon capture and underground storage use.


  • Identify the relevant design issues and technical criteria
  • Screen 17 wells and identify high-ranked candidates
  • List technical issues and make suitable recommendations


  • Reviewed available well data
  • Developed 12 technical criteria
  • Screened / ranked the wells and identified most attractive candidates
  • Generated conceptual designs for workover and sidetrack options
  • Assessed technical issues and made 41 technical recommendations


  • External carbonic acid corrosion of existing carbon steel production casing above the production packer – subsurface scenarios and load cases
  • Pressure tests on old production casings
  • Annulus / formation fluid freezing during CO2 injection transient events
  • Wellhead specification
  • External corrosion of surface casings and ongoing exposure to aquifer cross flow in sand-prone overburden
  • Well architectures and practical hole sizes
  • End of CO2 injection abandonment design


  • Identified preferred candidates
  • Screened out wells with technical walk-away issues
  • Framed the issues, risks and areas for further technical work and risk assessment
  • 133 page report