The need for higher capacity cranes that also meet strict new emission standards is leading to a rise in refurbishment and replacement projects on the west coast of the USA. As a result, construction and engineering management expertise at InterAct is in high demand.
The company recently managed a $15 million crane removal and replacement project on an oil platform in Alaska for a major international oil and gas client. The project involved completely replacing one crane pedestal and two ageing, pedestal mounted, diesel cranes. The new diesel powered, hydraulic cranes have 30 m booms with capacities at 23 m radius that are 56 and 140% higher: the north crane’s static capacity jumped from 7.3 to 11.3 t, and the south crane’s rose from 11.3 to 27.2 t.
“The client was looking to replace the cranes because of safety and capacity reasons. The old north crane had mechanical controls, not hydraulic, which have a history of dropped loads and damaged components because the mechanical clutches could not engage,” explains Jeff Hall, construction manager, InterAct.
“The original cranes’ limited capacity would also have required a lot of disassembly of wireline units or other drilling components to support drilling, well interventions or well workovers. Therefore, putting bigger cranes in meant a lot of possible cost savings, as the client could mobilise single units without disassembly and reassembly. This need to replace old cranes is occurring across the west coast as diesel-engine emission standards become stricter. Clients are choosing electric-powered hydraulic cranes as cost-effective solutions with lower maintenance requirements and zero emissions,” Hall concludes.
InterAct’s competitive rates, safety-conscious approach, previous experience and independence from other oil and gas projects in Alaska made it the ideal choice for the overall project management of the crane replacement work. The client awarded InterAct a significant contract to secure two construction managers to oversee the entire job and two crane-rigging specialists to help ensure adherence to a strict behaviour-based safety initiative.
InterAct’s lead construction manager, who had rotational back-up from a colleague, was charged with coordinating all the project activities and the other contractors, which included CH2M Hill, Hopper Engineering and Sparrows.
CH2M Hill worked closely with InterAct to maintain the schedule, while Hopper Engineering provided all the structural work for the project and Sparrows manufactured the cranes, supplied a temporary crane and provided the installation crew for the job.
The 32-t capacity, 36.5-m boom, temporary rental crane was transported from Louisiana to Alaska by truck, barge and boat, and then assembled on the drill deck of the platform so it could remove and install both new cranes and the new pedestal.
BMT Tank fabricated the new pedestal for the south crane in Elma, Washington, and shipped it by barge to Cook Inlet, where it was welded to the platform at the drill deck and production deck elevations. Deck reinforcement was completed beforehand so it could handle the new, higher-load-capacity crane. The original 18-t pedestal was removed in a single lift. The north crane installation involved removing the upper 2 m of the existing pedestal and welding a new transition pedestal with flange onto the remainder.
The client had originally planned to use a barge crane to carry out the work, but InterAct, in conjunction with the client and its marine adviser, devised an alternative solution using a temporary, platform-based crane, which meant substantial cost savings.
For this option to work, however, the team had to secure a dedicated work vessel for the project. Previously, the client was getting support twice a month from a workboat that was shared among all the platforms in the area.
After several months of reviews, the client agreed to the new plan and secured a work vessel from the Gulf. “It provided a major advance in their logistics, as they now have a dedicated workboat that they can use for their platform. It was also much safer and more flexible for this project, as we did not have to make dynamic lifts from the moving ocean to a fixed platform,” says Hall.
Safety was of paramount importance throughout the project, as the client would have considered the project a failure had there been just one lost-time injury. InterAct therefore enforced strict protocols to ensure safety and the whole project team managed to clock up 23,000 work-hours without an incident.
One mechanical engineer stopped work when he felt the bolts he was adjusting on the crane were not tightening properly. “Stopping a job costs money, but I backed the mechanic’s decision and the next day I was very glad I did,” says Hall. After taking the bolts apart, the team discovered that they had stretched and were not the bolts that had been ordered.
Working with such large pieces of equipment can present other challenges. One big technical challenge InterAct faced was how to move the old pedestal from vertical to horizontal safely, and likewise how to get the new pedestal from its horizontal position on the ship to the vertical.
InterAct’s rigging specialists came up with the idea of welding a padeye onto the pedestal and having two padeyes on the deck to form a clevis into which the team could put a pin to create a pivot point. Sparrows was then tasked with designing a jig rated to take the force of the pedestal.
“This was a good example of collaboration. We had InterAct guys developing the initial concept, a design by Sparrows, the pedestal fabricator installing the padeye on the new pedestal and a fabricator in Alaska making the jig that went on the deck,” says Hall. “It was a technical challenge that worked out really well.”
The offshore work for the replacement project was completed on schedule. InterAct’s performance has since led to further contracts from the client. The company has also been contracted by several offshore operators in California to assess crane removal and upgrading options.