RotaBolts for Ground-Breaking Subsea System
RotaBolts are being used on a ground-breaking new subsea well intervention system designed to operate in up to 10,000 feet of water. Expro’s deepwater
AX-S (‘access’) system has been developed with innovative technology and features RotaBolts on all its key pressure containing flanges. The new system is designed to help increase the extraction of oil from deepwater wells by providing a safer, deeper and more cost effective alternative to conventional systems.
Expro first used RotaBolt® technology on its Open Water Lubricator Valves, used as a safety testing device in open water riser systems, back in 2007 but it was also the track record of RotaBolts in achieving bolted joint integrity in other subsea systems that attracted the AX-S engineers to the use of tension control technology again.
“Expro’s AX-S system extends the operating envelope for subsea well intervention far beyond the current limit,” commented Matthew Law, Engineering Manager for the project - “Applying the correct bolt pre-load to achieve joint integrity on the system’s pressure containment flanges was essential. We knew RotaBolt’s record on other subsea applications and they became an obvious choice for us.”
In total seven different sizes of RotaBolts are being used on AX-S, ranging in size from ¾ inch up to 3 inches. The fastener’s unique tension control technology not only achieves the correct tension across the bolted joint at installation, but it also continues to monitor and maintain the tension throughout the life of the bolted joint.
The ability to finger test each bolt’s RotaCap to check that no tension has been lost, continues to be a major maintenance and operational benefit in many different sectors.
DNV (Den Norske Veritas) has independently provided hazard assessment and technical qualification throughout the development and testing program and
AX-S is due to enter into field trials this year with Expro’s partner on the project – BP. It is being described as a “step change in well flow management of subsea wells.”
World’s First Integrated Bolted Joint Tension Control System
The two global leaders in tightening control and bolted joint technology, Hytorc and James Walker RotaBolt, have launched the world’s first fully integrated tension control system for assuring bolted joints – Integrity. Described as fool-proof, the new system quickly and easily installs its fasteners at the correct design tension without even having to remove the tool from the bolt during the process. Together the unique tool and fastener ensure that the correct tension is achieved every time and then fully maintained throughout the life of the bolted joint.
Failures of critical bolted joints can be disastrous and over 90% of all failures can be attributed to insufficient bolt tension at installation. The two companies have developed Integrity as an integrated system with the science of tension control at its heart. It features the world’s first tightening tool to incorporate the technology used during the production of RotaBolt tension control fasteners within its specially developed checking device. The tool automatically senses when the special cap has locked on top of the fastener and then immediately cuts off the hydraulic tightening power.
“Integrity is set to become the industry standard wherever reliability and safety are of paramount importance in bolted joints,” commented Rod Corbett from James Walker RotaBolt, “it is optimum bolt tightening - simple, accurate, fast and fool-proof.”
The new Hytorc tool with its accuracy and capability, coupled with RotaBolt’s tension control and 100% load test calibration, has resulted in the most advanced technology-led system in the world. It delivers the speed and flexibility of fully integrated hydraulic torque tightening, combined with tension control accuracy to +/- 5%.
As a complete system, it quickly and simply installs to the correct design tension and then monitors and maintains that tension throughout the life of the bolted joint through the control technology incorporated in each RotaBolt.
