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Thinking ahead to decommissioning

As anyone with experience of running a vintage car will know, the maintenance required to keep such a vehicle on the road will be different for daily use compared to a machine that is only brought out the garage sporadically.

There are many similarities with the running of offshore cranes, particularly those on older platforms in the North Sea and Gulf of Mexico.

It isn’t always easy to take a long term view when budgets are being scrutinised. Going with a holistic approach and looking at the bigger picture can, however, be particularly cost effective when it comes to the life of platform cranes.

The need for an appropriate and effective maintenance strategy during the operation and maintenance phase of a platform is, in the main, well understood. As the installation ages and moves nearer to the decommissioning phase other factors come into play and maintenance can often take a back seat in the priority of operators.

It is at this stage that we should consider how maintenance and inspection programmes impact on the future decommissioning strategy. Just as thoughts turn to cessation of production and plug and abandonment, thinking a step on to what the procedures will be for decommissioning could be particularly cost effective for the long run. As preparation for decommissioning starts, this is when the cranes will likely be taking on the most demanding phase of their lifecycles.

Establishing the limitation in performance capability of the existing crane(s) early, be it lifting capacity, reach or hoisting speeds is key. Understanding the likely types of lift, weights of load and size and frequency of lifting activities to be undertaken during a decommissioning project is essential in assessing the mechanical handling options available that will deliver the most efficient approach and bring most value to the project.

There are varying maintenance strategies – such as preventative or predictive maintenance or even a minimal maintenance strategy where we manage the risk of breakdowns – that support the different options for lifting when the decommissioning phase occurs.

Maintaining the existing cranes, utilising a rental crane or purchase of a brand new crane are three common strategies, each of these have merits and drawbacks. At first glance, maintaining the existing cranes seems like the obvious choice but if it is not going to be up to the required task you could run a minimal maintenance strategy then take on a new crane, rented or bought, when the heavy lifting starts. Buying a new crane could be the preferred option for firms decommissioning several platforms when it could subsequently be reused across each platform or it may be that rental is what brings most value to the project.

Knowing what you are aiming to achieve plays a crucial role in informing how you get there and it pays to think ahead.

At Sparrows, we have devised a five step plan:

  1. Understand your lifting needs
  2. Engage the experts for advice
  3. Establish a maintenance strategy that fits the decommissioning strategy
  4. Review crane options
  5. Review the lessons learned.

Following this approach enables clients to examine all their options before they commit to a strategy that doesn’t tie-in with their long-term aims.

Oil and Gas UK’s Decommissioning Insight 2015 Report estimates 79 platforms will be decommissioned on the UK Continental Shelf by 2024 with a further 24 in Norway. The cranes on these have each been through varying workloads and will have different demands placed on them with decommissioning. Thinking ahead will enable us to tailor our approach and provide the best value over the long-term.

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