OSVs & CABLE INSTALLATIONS
FLEXIBLE SOLUTIONS FOR SURF & CABLE INSTALLATION ACTIVITIES IN CHALLENGING ENVIRONMENTS
BY MIKE MORRISON, HEAD OF CABLE AND PIPE LAY SOLUTIONS, AT SPARROWS GROUP
In the offshore industry, while standardisation has become a key theme in recent years there are many areas where there is not a one-size-fits-all solution. When planning a project, different regions have varying complexities with weather, water depth and equipment availability all to be considered.
As the industry discovers and explores fields in more challenging environments, demand is growing for umbilicals, risers and flowlines that are longer in length, larger in diameter and more robust than the traditionally used product. For the SURF and cable installation sectors the capability and functionality of the equipment being used is changing and there is a drive for innovative solutions.
Being able to safely handle such a product and ensuring it is deployed within its design limitations can be a complex task. Having the best equipment available for the job is crucial but meeting project specifications can also be a costly process.
When it comes to tensioners and reel-drive systems (RDS), there are a variety of different sizes available for sale and rental. Instead of purchasing a new tensioner or building a bespoke RDS to suit the job, an increasingly attractive option is customising an existing system to meet the needs of the project.
Whether for use on a rental or pre-purchased tensioner, engineers can modify and upgrade existing equipment to increase the handling and control capabilities, allowing them to manage larger products and more complex spooling or installation methods. A further benefit of this approach is the option to return the tensioner to its original state, meaning the client receives a diverse system capable of operating in different setups.
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www.sosmagazine.biz | July 2017
www.sparrowsgroup.com
Above: Tensioner installed on spooling tower. Bottom right: Tensioner before modifications.
Challenging environments As an example, Sparrows Group was recently contracted to modify a tensioner for spooling of an umbilical to a vessel carousel for a deepwater project in the Atlantic. Due to the product being tied back to an FPSO in potentially rough waters, the umbilical will suffer extreme fatigue cycles in its lifetime meaning a larger product is required than typically laid in shallower waters.
The client rented a 10Tonne tensioner to be mounted on the vessel 2000Te carousel’s vertical spooling tower for the spooling and installation of the umbilical.
The challenge for our client was in spooling from a carousel to a lay system. The umbilical had an outer diameter ranging between 287mm and 453mm with a very large potted clamp on the FPSO side that was also required to pass through the tensioner at 610mm.
The tensioner initially had a product range capability for track opening of 40mm to
400mm, therefore the track opening needed to be increased. The tensioner was still required to be able to fully close tracks for a smaller product as an initiation line of around 100mm was to be spooled onto the carousel.
To achieve this, the tensioner was engineered to accommodate a larger track opening. This involved cutting the mainframe supports, inserting a bolted connection and puck piece to increase the opening range of the tensioner. The guide bars were mounted on a new support piece to facilitate the larger top track opening.
An additional mounting position for the tensioner bottom track was manufactured and
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