Focus on offshore decommissioning

Published 18 December 2019

Read the interview and learn more about offshore decommissioning with our prominent course director Ian Prince.


Ian Prince_400x400

Ian Prince
Decommissioning Consultant

Principle Decommissioning Services, United Kingdom

1. You were the implementation manager for the decommissioning of Brent Spar in Norway. Tell us about your role

Initially, I was the project manager for an Anglo/Norwegian Consortium leading a competitive FEED to come up with the winning solution for the decommissioning and disposal of Brent Spar. Following success in winning the Contract from Shell, I led a Norway based team through design. During the execution phase, I was responsible for the implementation. I was based in Vats, the Norwegian Fjord where the decommissioning took place. My main duties were ensuring that all necessary resources and equipment were available to meet the program and ensuring we had effective solutions for all problems.

I followed the project through to close-out and all in all I was involved for 3.5 years.

2. What were the biggest challenges?

There were many challenges considering this was a unique decommissioning project with high media visibility.

The biggest challenges related to safety and environment i.e. H2S was present in the Brent Spar storage tanks at levels of circa 500pp creating a major safety hazard. The solution itself was a significant project.

Another challenge was disposing of the 50000t of storage tank water once it had been cleaned, this also was a significant challenge requiring liaison with Norwegian regulators.

Disposal of LSA was also a significant issue which required involvement of both UK and Norwegian regulators and actually took circa 2 years to resolve.

3. Many installations in the North Sea are approaching the end of their lives. What do you think is the best solution?

It’s often said, OSPAR legislation requires that platforms should be removed with some exception for the very large structures, via derogation.

Decommissioning and removal gives no value, consequently the driver must be low cost without prejudice to safety and environment.

There is no one single solution and each structure should be viewed on its own characteristics.

Consideration should be given in the late life of a platform to decommissioning rather than leave it to the end as a separate project.

Looking at the ‘bigger picture’; carrying out decommissioning in campaigns, also giving maximum flexibility to contractors, could result in lower cost.

4. Do you see rigs-to-reefs as an option?

Prior to Brent Spar, rigs to reefs in the North Sea were being seriously considered but OSPAR decision 98/3 effectively killed that off.

Rigs to reefs have been successful in many parts of the World but one needs to consider the following for the North Sea.

  • Rigs to reefs must not be an excuse for ‘dumping’ and just leaving platforms where they are
  • In the UK an Operator has liability for any remains in perpetuity, consequently, a mechanism would be needed to transfer liability from Operator to reef owner
  • The cost of removing a jacket and transporting to a reef site may be greater than transporting to onshore for recycling
  • Topsides, unless cleaned and non-ferrous materials removed, will have to be removed to onshore for recycling
  • IMO require 55-meter clear water depth

5. You were the trainer at our preceding events. In your opinion, what are the key benefits of attending Fleming. training?

  • The course covers all aspects of decommissioning from strategy and planning, through engineering, execution and closes out
  • Delegates take part in exercises which are typical of a decommissioning project
  • An opportunity to discuss with other interested delegates what their issues and concerns are
  • To hear lessons learn from real projects with case studies


Decommissioning of Offshore Oil and Gas Installations
10 - 12 March 2020 Amsterdam, Netherlands