Cutting Underwater Technologies Ltd. (CUT UK) has recently completed a major project on behalf of Subsea 7, Offshore Angola. The project, which required a number of cuts at a water depth of around 1235m, was unusual due to the shape of the target that had to be cut. In four of the 15 cuts that were to be carried out the Diamond Wire Cutting Machine (DWCM) had to cut through both the 970mm diameter Sleeper Pipe and the 2390mm width of the Sleeper Support Feet in one operation.

CUT UK, were able to call upon the expertise of their Parent Company, Tecnospamec who designed, built and tested a one-off, special build DWCM. The DWCM was so configured that it would allow this dual cut requirement to be carried out whilst retaining the flexibility to perform a standard cut through just the pipe section. A test cut was carried out, onshore, in Aberdeen, by CUT, within six weeks of the order for the machine being placed.

Following the successful trial the DWCM was shipped (along with a second unit) to Angola and loaded aboard the project support vessel. The DWCM was deployed using the vessel’s crane to the target depth with final positioning being carried out using a Workclass ROV. All control and operational functions (clamping, wire speed, drive and feed) of the DWCM were powered by the WROV. This flexibility allows CUT’s diamond wire machines to work without limitation in water depths outwith the operating parameters of other cutting technology. Each Sleeper Pipe cut took around 1.8 hours whilst the combination Pipe and Feet cuts required some 3.4 hours to complete.

Special Build DWCM Shown in CUT UK’s Aberdeen Facility Prior to Shipment to West Africa

With this phase of the work now complete, Matteo Mosca (Head of Engineering CUT UK) commented, “This venture has been extremely challenging in relation to both timescale and the technical challenge that it presented. The initial design, build and test of the DWCM within such a short time frame pushed all concerned to the limit to ensure that all parties, both internal and external, co-ordinated their efforts to maximum efficiency. The trial cuts and WROV interface tests, always a time of concern with a new design machine, were successfully carried out at the Client’s facility in Aberdeen. Then, once deployed to site, the DWCM interfaced seamlessly with the WROV thereby allowing all the required cuts to be carried out successfully.” He continued, “Overall I believe that everyone concerned with this project can be pleased with their contribution to what has been a most successful undertaking.” John Rhodes, the Subsea 7 Project Manager was equally pleased with the results achieved to date. “CUT UK have,” he said, “demonstrated their ability to meet tight deadlines and perform what has been asked of them in a most exemplary manner. Their site personnel integrated well with both the vessels staff and other contractors whilst performing their tasks efficiently and, most importantly, safely. We look forward to working with them again in completing the project in the near future.”

Photograph taken at 1233m showing the Diamond Wire Cutting Machine clamped in position on the Sleeper Pipe with the WROV in position supplying the necessary hydraulic power. Cutting is just about to commence and will continue until both the Sleeper Pipe & Feet are severed.