Claxton’s NT-2 Drilling Riser Handling Tool saves $2.9 million on a single campaign

Fast, effective and safe handling of drilling riser systems is essential for the success of many offshore operations. The industry’s shift towards projects in deeper water locations and more challenging environments has brought the challenges associated with riser handling into sharp focus. These challenges have prompted significant developments in the systems and methods that the industry applies to handling drilling risers. Claxton has been at the forefront of these developments and has rethought a number of solutions.

Rethinking drilling riser handling…

An impressive example of rethinking is Claxton’s new multipurpose, hydraulically actuated NT-2 riser running/handling tool. In its first field application, the tool was used to install and pressure test a 6,300-psi riser for a project in the Norwegian Continental Shelf. The new approach enabled the field operators to cut four and a half hours from each run, thereby delivering a $2.9 million saving over the five-well drilling campaign.

Claxton NT-2 Drilling Riser Handling Tool
Claxton’s NT-2 Drilling Riser Handling tool, shown here running a riser offshore Norway. 

DNV-approved and meeting all the relevant Norwegian petroleum industry NORSOK standards, the tool is designed to handle the riser top tension joint by making-up to a GE Oil and Gas NT-2 (commonly used to interface with the blowout preventer – BOP). Using a dedicated, ATEX-approved hydraulic power unit with its own umbilical, the tool can be automatically locked onto the connector in just a few seconds. Following completion of the connection make-up the connector seal can be tested by means of a low pressure interface test. The system also features indicator rods that provide visual confirmation of when the tool is firmly attached and a manual override device to unlock the tool if necessary.

Engineers who use the system can pressure test the top tension joint to 7000 psi while holding a tension in excess of 300 t.

The tool, which Claxton developed over nine months of designing, prototyping, testing and certification, makes it easier to pressure test a complete riser system while holding the string under tension. Engineers who use the system can pressure test the top tension joint to 7000 psi while holding a tension in excess of 300 t. The tool also provides a contingency for applying 400 t of tension to the riser system once it is landed on the wellhead/ subsea Xmas Tree but before installation of the BOP, though, in this case without internal bore pressure.


Claxton drilling riser handling tool
The NT-2 Drilling Riser Handling Tool was the result of extensive testing and riser running experience.

Claxton developed the tool with the ability to handle riser tension joints fitted with a Claxton slimline riser tension ring. This helps to save rig time, reduces the exposure of personnel on the Texas deck and can eliminate the need for scaffolding, which is often required for operator access when using a manual tool to handle the riser tension joint with its BOP connector. The result is significant time savings and a major reduction in the risks associated with handling operations.

Following its successful introduction to the North Sea, Claxton offers the hydraulic tool to all of its riser clients as part of a company-wide drive for better efficiency and safety. Its value is underlined by the fact that two leading operators have purchased tools for their own inventories.

Learn more about Drilling Risers from Claxton here.

High pressure drilling riser animation

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