Cutting Underwater Technologies Ltd., based in Aberdeen, Scotland, is proud to have been active in helping Aker Solutions to reach their targets for this project.
Use was made of CUT UK’s innovative, patented, diamond wire cutting technology to sever the jacket legs prior to re-floating the complete jacket.

In addition to the advanced technology that CUT were able to offer there was the absolute guarantee that, once the diamond wire had emerged from the target being cut, there could be no doubt that the target pile had been severed completely.        The work in 2008 was the culmination of four years of co-operation between CUT UK and Aker Solutions following the successful completion of a trial cut in 2005.

Frigg DP2 jacket structure shown with attached Buoyancy Tank Assembly (BTA) structures just prior to being re-floated

         The trial cut, carried out under a compressive load of 400tonnes, demonstrated the ability of the Diamond Wire to pass through the target without either breaking or getting ‘jammed’ because of the ‘cut-gap’ closing. Later in that year (2005) three initial cuts were carried out on the DP2 jacket legs and piles, all of which were completed without problems.

Returning to the field in 2007 two separate campaigns resulted in a further 15 cuts being performed.        Deployed from the NSV Botnica over two final campaigns in the summer of 2008 CUT UK again utilised one of their specialist 64 inch Diamond Wire Cutting Machines (DWCM’s) to carry out a combined total of 17 cuts which, when completed, allowed the jacket structure to be re-floated and subsequently towed to Stord.      The majority of the cuts were made on double walled (56” x 2 ¾”w/t and 42” x 2 2/3”w/t) concrete filled piles around which, to comply with current legislation, dredging operations had been carried out thus allowing the cut to take place below the level of the seabed.   DWCM and Guide Ring shown clamped to test piece set up for trial cut under 400t compression loading.

Deployed to the seabed in its own basket the 64 inch Diamond Wire Cutting Machine (DWCM) was then ‘picked up’ and ‘flown’ to the cutting site by a Workclass ROV (Remotely Operated Vehicle). Once at the correct location the DWCM uses its own integral clamping system to grip and hold itself in position on the pile. Then, using hydraulic power supplied from the surface the Patented, 4th Generation, Diamond Wire is ‘driven’ through the target by the CUT UK representative through use of a specially designed Control Panel. This ensures that the correct tension is maintained in the wire feed to ensure optimum cutting conditions continue throughout the cutting operation.        A ROV is used throughout the cutting operation to provide video feedback to the operators on the surface allowing them to monitor all stages of the cutting procedure from start to finish.

Jan Rødseth Aker Solution’s Project Manager for this project stated, “The Frigg DP2 Jacket removal project was a success. No less. For the first time, a complete 12.000 tonne jacket was brought to shore for decommissioning. CUT UK Ltd was entrusted to cut all piles, below the seabed. It is my pleasure to conclude that these tasks were conducted to our full satisfaction, within the schedules and budgets. CUT UK Ltd has, through highly competent operators and well functioning equipment contributed greatly to our mutual success.

Screen shot showing the diamond wire that has passed through the target material following a successful cutting operation

Furthermore, Dino Vallarino, CUT UK’s General Manager commented, “We at CUT are very proud to have been involved in such an innovative and successful project as this. Throughout the whole time of this venture CUT and Aker have maintained a good and open working relationship which has, without doubt, contributed to the accomplishment of all project goals. We are especially pleased that each campaign was completed on time, in budget and, especially, with no safety incidents.”      As a follow on to their work in assisting with the removal of the DP 2 Jacket CUT UK have recently been awarded a contract by Aker Solutions for the demolition cutting of the jacket in Stord Harbour.