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Project profile: Fast-track 16" OD subsea drilling riser system


We delivered the riser and equipment package on time despite having to manufacture 7x12m 14.3” ID riser joints with NORSOK flanges and a customised Torus-2 wellhead connector that would run through the rig’s rotary table. Claxton was able to deliver the riser at such short notice due to our fast-track (in-house) design engineering capability and an extensive supply chain that can call on multiple sources for manufacturing – just one example of how being independent of major riser suppliers and fabrication houses enables us to enhance our client service.

The tight supply-window meant we had to take a number of innovative approaches to ensure could meet the delivery date – just one example of this is the C-plate adaptor we developed to take the place of a more traditional riser-spider (which couldn’t be built or sourced within the condensed delivery schedule)

The C-plate interfaced with the rig’s Rotary Bushing and used a tiered-plate design to accommodate NORSOK and API flange profiles – allowing the riser to be held in place during running.

The modified C-Plate we supplied enabled running of NORSOK and API flanges through the same riser spider.

The four c-plate configurations shown above are as follows:

  1. Standard NORSOK C-Plate
  2. API Adaptor
  3. Standard NORSOK flange engaged with C-Plate
  4. API flange engaged with C-Plate

We also delivered a new bolt-torqueing spread to enable efficient running and make-up of the system.

Thinking about your riser requirements?

Claxton’s riser engineers have been supplying risers since the early 1990’s and we’ve been responsible for over 190 riser projects since 2005 alone.

Learn more about how we can make your next project happen by downloading our riser case study pack.

Risers & tensioning case study pack
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Drilling Riser and Tensioning Case Study Pack

Download the Claxton drilling riser and tensioning case study pack to discover how we have saved clients time and money through innovation.