Decommissioning & End of Life

Riser & Subsea Decommissioning

We help operators solve their decommissioning challenges holistically, bridging the gap between operations and decommissioning teams, resulting in significant cost savings and a more efficient transition of activities.

Discuss a project with us

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Discuss a project with us

Get in touch

Removing aged subsea architecture after years of service requires a multi-disciplinary team to carry out the many tasks involved. Our holistic planning approach allows operations to continue right up to cessation of production and results in significant cost savings. 

We help solve a range of common decommissioning challenges and do this by applying our thorough understanding of the safety philosophy of industry design codes and prior practical experience of decommissioning. We identify critical components and the key interactions between subsea disciplines and develop appropriate methods for removing obsolete infrastructure safely. Our long track record in equipment detailed design, installation engineering and integrity management can also provide a valuable insight into the requirements for reverse engineering, removal and potential re-use. This has helped clients overcome issues such as a lack of knowledge about equipment condition and time-dependent degradation safety while remaining compliant with the relevant legislation. 

For larger projects, we collaborate with other Acteon Group companies combining the specialist skills and technologies of Acteon’s individual service companies to provide innovative and flexible solutions to drive operational efficiency. Working together, particular consideration is made to the interfaces and interaction between activities such as well P&A, subsea recovery and facility removal as much as the challenges of each activity individually. 

After working with us, our clients have the tools to help overcome the divide between operational and decommissioning teams as pre-work to facilitate post-CoP activities can be scheduled into work programmes whilst the asset remains on-line. Not only does this generate cost savings but also provides an effective mechanism for managing the risks and challenges through late life operations and into decommissioning. 

Key Services 

Planning & Supervision Services 

  • Data gathering and review of historic records

  • Cost comparisons and concept selection

  • Holistic field-wide pre-planning studies

  • Vessel selection and feasibility studies

  • Feasibility of riser re-use

  • Scrap yard selection

  • Offshore supervision


  • Reverse installation analysis of risers, flowlines and moorings

  • Riserless abandonment system design

  • Cutting sequences

  • Selection of cutting tools

  • Operational procedures and storyboards

Lifting Assessments 

  • Assessment of platforms, manifolds and flowlines

  • Design and analysis of lifting members and tools

  • Removal of concrete in piles

  • Procedure generation

Project Experience 

  • Petrofac – Cendor MOPU decommissioning & conductor preparation

  • PCPPOC – DANA freestanding conductor platform analysis

  • BP – Foinaven decommissioning efficiencies study

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