Fast track Middle East drilling riser tension system supply

Claxton’s experience with drilling riser tension systems and rings  recently proved invaluable in the Middle East with the ultra-fast supply of two new riser tension systems. In meeting the short lead time, Claxton’s team ensured the operator’s campaign stayed on track.

Drilling riser tension system saves the day for Sharjah rig supply

A UAE-based rig builder tested Claxton’s flexibility when it asked the company to provide modified  drilling riser tension systems for two new jackup  rigs at very short notice.

Similar rigs had left the rig builder’s yard in Sharjah with 50-t tension systems built according to a standard specification, but the two latest rigs required systems capable of applying 150 t of tension to the drilling riser. The challenge was that the new systems had to be fitted within the existing rig layout. Claxton’s project manager Will Robinson describes the project as a retrofit into a newly built rig.

Robinson says, “We were asked to design and supply a drilling riser tension system that could be installed on the drive deck beneath the drill floor without any serious structural changes to the rig to withstand the higher loads.”

Drilling riser tension rings and systems have been pioneered by Claxton's riser team

Claxton’s riser tensioning solution

Claxon devised a system that uses four hydraulic jacks pushing upwards against one of the company’s proprietary slip-activated tension rings. This tension ring, which was of a larger diameter than usual and so required redesigning, was chosen over a standard positive-grip tension ring because of its ability to handle the asymmetrical loads that resulted from having to work within a prescribed jacking layout.

Claxton received the initial enquiry in 2010 and its engineers began to think about the design of the system. When the firm order came, however, the first system was needed very quickly.

Signed, sealed and delivered… 

Claxton carried out detailed design work and manufactured and delivered the first drilling riser tension system, comprising tension cylinders, tension ring, ATEX-approved hydraulic power unit and a pipe centralizer, in just six weeks, about half the normal time for such an order. The second system was not required within such a tight timescale, but it was still delivered in about nine weeks. Will Robinson summed up the team’s achieved in keeping to our client’s challenging schedule:

The project illustrates perfectly what Claxton is all about.

The rig builder came to us with an enquiry that required a tailored solution that had to be supplied against the sort of timescales more associated with an off-the-shelf order. We are proud of our ability to take these combined technical and schedule challenges in our stride.

You can learn more about our drilling riser tension rings, systems and overall drilling riser  and conductor tensioning supply capability here.

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