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West Africa Deepwater Abandonment Campaign

Zenith were awarded a well intervention engineering contract by CNR to review the potential cause of two well failures (loss of sand control) in Baobab field, offshore Ivory Coast. Well intervention is planned to clean out and remediate. To maximise value from the intervention and future well planning it was key to identify the likely cause of failure whist remediating the wells; enabling them to be brought back on stream and reliably producing sand-free to drain what would otherwise become by-passed oil reserves.

Objectives

  • Complete intervention engineering study to identify the potential cause of the well failures.
  • Allow client to remediate wells successfully to be brought back on stream

Method

  • Review well histories, reports and production data
  • Support 3rd party studies and oversee all technical modelling (CT and hydrate modelling)
  • Project Risk Assessment
  • Identify intervention options
  • Perform market review of technology available
  • Prepare intervention "Basis of Design" document
  • Assist client with rig selection process


Challenges

  • Design to be conscience of hydrate risk
  • Clean out method with narrow PP / FG window in deepwater
  • Selection of logging tools to determine screen failure mode minimizing runs
  • Selection of remediation method to maximise well PI whilst minimizing erosion risk

Outcomes

  • Identified cause of well failures
  • Prepared project risk assessment
  • Identified preventative measures to avoid repeat of failures
  • Prepared basis of design document covering recommended intervention operational steps and methodology
  • Allowed client to make informed decision on rig selection to perform the works