North Sea Decommissioning

The Operation

While carrying out decommissioning operations on a North Sea field, the operator reported a lack of accurate and up-to-date information of some subsea hardware, mainly the result of years of intervention following its installation in the 1970s.

With our customer – a marine contractor – already scheduled to be infield conducting decom operations, it was the perfect platform for us to carry out adhoc 3D scanning while on site.

The Challenge

Simply put, the main challenge involved co-ordinating a 3D scanning operation which would meet the client’s required accuracy statement, to be completed during vessel down-time, during breaks in other operations.

The Solution

Viewport3 mobilised equipment and personnel to an anchor handling vessel which had been selected for the operation.

The 3D scanning targets were pre-planned, and the items to be scanned were acknowledged and understood by all parties.  While infield, the operations had to be timed to permit the 3D scanning to take place during the available windows. During the scanning process, an additional site was added to the survey list on client request, in order to assist in the removal campaign.

Verification was done onboard, in the presence of the client, ensuring that the coverage was indeed complete, and the efficiency of the operation onsite was undoubtedly aided by our extensive experience in subsea projects.

The Result

During the allocated windows of opportunity, Viewport3 3D scanned 16 separate targets. All results were verified onboard, and were within the parameters required by the customer.

This project proved extremely valuable for Viewport3. Our experience of subsea operations and inspection works allowed us to merge seamlessly with the vessel operations, while delivering high quality data for the customer which provided a platform to make smart decisions leading up to the removal campaign.

The delivery of accurate, up-to-date information on current subsea structures eliminated ambiguities and so reduced the risk posed by delays to removal of the structures and components during future decom operations.

In Numbers

Due to the seamless integration of our work into the vessel programme, no additional work was required beyond the timescale of the planned decom operations, saving costs associated with extra vessel days.