Jee aided a client in the creation of a risk-based inspection plan for pipelines which had been left in-situ within a decommissioned field in the Southern North Sea.
The pipelines included in the scope of work were all buried and had been subject to pre and post decommissioning surveys. The client was now required to agree a legacy inspection plan with OPRED for the pipelines in question and engaged Jee to support them with this.
Jee was asked to perform a survey trending exercise for the pipelines to identify the presence of any features that could present a hazard to other users of the sea, and to determine how the adjacent seabed was changing over time. The results of the trending exercise provided crucial information on the risk the pipelines posed, and the likelihood of the buried pipelines becoming exposed in the future.
Jee were also asked to develop a risk-based assessment process that the client could use for risk assessing any other of their pipelines that were decommissioned in-situ within the UKCS. To meet this objective, Jee developed a risk matrix tailored specifically for assessing pipelines decommissioned in-situ. The likelihood and consequence definitions in the matrix were made specific to decommissioned pipelines, and suggested inspection intervals were correlated against risk matrix positions. Jee presented the proposed risk matrix to OPRED and other stakeholders, along with the rationale that was used to build it and ultimately arrived a position where OPRED approved the client to use the risk matrix going forward.
Jee then risk assessed the pipelines within the scope of work against the approved risk matrix and developed a proposed legacy inspection plan which was then submitted to OPRED for acceptance.
The success of Jee’s project meant that the client now has a regulator approved framework for risk assessing all their UKCS pipelines which are decommissioned in-situ. The benefit this provides is consistency in legacy pipeline inspection planning.
For more information, visit www.jee.co.uk/decommissioning
To contact Graham Wilson, email graham.wilson@jee.co.uk, or call +44 (0)1732 371 371.