Decommissioning Engineering

Our expertise in structural analysis and risk based engineering assessments will help you optimise your decommissioning activities for subsea wells, platform wells, and other subsea infrastructure nearing the end of its design life.

Decommissioning ageing infrastructure poses significant challenges, often as a result of incomplete asset data or changes in design approach from installation to present day. Our structural analysis experts will perform accurate risk based assessments of your asset to help bridge this gap and allow you to identify and mitigate potential concerns early to ensure decommissioning operations are conducted as safely and efficiently as possible.

Our engineers have a thorough understanding of the safety philosophy of industry design codes and a practical knowledge of decommissioning operations gained from projects in the Gulf of Mexico, North Sea, Irish Sea and offshore Malaysia. Our long track in equipment detailed design, installation engineering and integrity management can also provide a valuable insight into requirements for reverse engineering and removal from experience gained in the original design and maintenance of the systems to be decommissioned.

We will work closely with you and your equipment vendors to help solve common decommissioning challenges such as the operation of modern, high specification vessels on obsolete wellhead designs, and time-dependent degradation including corrosion and subsidence.

Our decommissioning engineering services can be complemented by capabilities offered by other companies within the Acteon group, including casing cutting and retrieval tools and engineering, marine procedure management, lifting and retrieval services, and design of abandonment programmes.

Key Services

Subsea & Platform Well Abandonment

  • Strength, fatigue and stability analysis of riser, wellhead and conductor systems
  • Tensioning requirements of the conductor and casing during plugging and abandonment
  • Vertical well loading assessment
  • Identification of maximum tubing pull loads
  • Engineering criticality assessment
  • Corroded and displaced well integrity assessment
  • Original well build simulation for in situ loads
  • Definition of allowable pressures for abandonment operations
  • Vessel drift-off limits and watch circle assessment
  • Jack-up rig modelling
  • Jack-up barge cantilever assessment
  • Component analysis of crossover tools and existing connectors
  • Design of conductor strengthening systems

Lifting Analysis

  • Assessment of platforms, manifolds and flowlines
  • Design and analysis of lifting members and tools
  • Removal of concrete in piles
  • Procedure generation

Reverse Engineering

  • Reverse installation analysis of risers, flowlines and moorings
  • Riserless abandonment system design
  • Cutting sequences
  • Selection of cutting tools
  • Operational procedures and storyboards
  • Execution of turnkey platform removal

Planning & Supervision Services

  • Data gathering and review of historic records
  • Cost comparisons and concept selection
  • Vessel selection and feasibility studies
  • Scrap yard selection
  • Offshore supervision

Project Experience

  • Petrofac – Cendor MOPU decommissioning & conductor preparation
  • Centrica Energy – F3-8 well plug and abandonment from a jack-up
  • Interact – HRL Morecambe Bay abandonment riser
  • PCPPOC – DANA freestanding conductor platform analysis
  • Shell – Draugen well plug and abandonment wellhead system fatigue analysis
  • Chevron – Alder suspended well plug and abandonment fatigue analysis
  • BG – Everest subsea exploration well plug and abandonment fatigue analysis
  • TAQA – Cormorant UMC 13-5/8” wellhead system plug and abandonment fatigue analysis
  • BP – Na Kika F3 well plug and abandonment analysis with Ensco DS3 rig
  • BP – Thunder Horse 777-5 well plug and abandonment analysis with West Capricorn
  • BP – MC217-1 well plug and abandonment analysis with West Vela
  • Shell – Macaroni and Europa plug and abandonment analysis with Q4000
  • Shell – Popeye upper abandonment analysis with Atwood Condor