Mammoet has been hired by shipbuilder and ship repair company Damen Shiprepair to assist with a jack-up leg repair for the Noble Corporation drilling rig Noble Regina Allen, reducing the downtime of the rig during retrofit process.
Initially planned to be completed using one of Mammoet’s PTC large ring cranes, the project was instead performed by jacking-up the 22,000t drilling rig. With time ticking, Mammoet resourcefully navigated the project and came up with a solution to get the vessel back in service as soon as possible.
As a trusted partner, Mammoet was invited by Damen Shiprepair to visit Noble’s offices in Houston and present three different methodologies for carrying out the repair work to the leg.
“The first option we presented was performing the lift using a Mammoet PTC210 crane. It would see the crane positioned on the quayside and lifting and lowering the leg into the vessel from above.
“The second approach was to bring a small crawler crane onto the deck of the vessel and have the repair carried out from above. The third solution was to lift the vessel using Mammoet’s Mega Jack 5200 system and carry out the repair from underneath,” said Ruud Jansen, Commercial Manager at Mammoet.
The Mega Jack 5200 has been used for jack-ups of great size and scale. The largest of these was a topside of 42,000t. It also offers quick mobilization and assembly, so this solution was chosen to fit the project schedule.
A configuration of six towers of the Mammoet Mega Jack 5200 were used, each with a capacity of 5,200t. Small mobile cranes and forklift trucks were used to assemble this equipment. Once all the jacks were in place, the rig was lifted to a height of 35 meters.
Because the leg section measured 70 meters tall, it was cut into two parts to fit underneath the rig. Each section was moved into position using Mammoet Self-Propelled Modular Transporters (SPMTs).
The first section was driven into position under the rig and then lifted by the rig’s jacking mechanism.
The process was then repeated for the second section, which was welded to the first by Damen Shiprepair, forming the complete jacking leg.
The operation was carried out the job in just three months and the downtime of the rig was significantly less than what it could have been, according to Mammoet.