High-Strength Synthetic Mooring Lines Weathered Hurricane Katrina Undamaged
BY KEN NORBERG, EDITOR
Synthetic mooring lines, like these being loaded for installation, are increasingly being used in offshore mooring .The Red Hawk oil platform in the Gulf of Mexico was designed to survive the worst storm imaginable. And that’s exactly what this first-of-its kind floating oil production facility faced when hurricane Katrina hit.
With winds exceeding 150 mph, Katrina ripped other platforms from their rigs, snapped anchor lines, destroyed nearly 200 platforms, and halted almost half of the Gulf’s oil and gas production in the summer of 2005.
But south of Louisiana in 5,300 feet of water, mooring lines made of high-strength polyester kept the Red Hawk platform secure to the seabed as it was slammed by the ferocious winds during the nation’s most destructive hurricane.
Just a half day after being evacuated, the crew returned to the platform to find little damage – and all systems a go.
RED HAWK TESTED
Robert Guldi, product manager for Whitehill Manufacturing, the supplier of synthetic mooring ropes used on Red Hawk, was confident the system would work as specified because of successful extensive pre-installa-tion testing.
“This was the first time we were designing a mooring system to these specifications – it was built to withstand the worst conditions and maintain its strength in a 100-year storm event,” he said. “Little did we realize, it would be put to the test.”
A tremendous amount of engineering goes into an oil platform mooring system, said Alan Giangregorio, vice president, global marketing of Performance Fibers, a leading supplier of polyester fibers and other advanced materials. Companies like Performance Fibers and Whitehill work together closely to develop fiber properties that match each oil mooring platform’s unique demands.
“Oil mooring platforms have to maintain their exact position over the course of several years and under a variety of environmental conditions,” said Giangregorio. “Performance Fibers’ 1W81 polyester fibers with SeaGard® marine overlay finish are designed with the correct balance of strength, modulus, and creep properties to meet these stringent long-term design requirements.”
WORLD’S FIRST CELL SPAR
Unlike the traditional semi-sub-mersible oil platform, Red Hawk was designed with the world’s first cell spar, a floating platform tethered to the ocean floor that must maintain proper tension so it stays over the drilling area.
The Red Hawk cell spar’s hull is formed of seven hollow tubes, each 20 feet in diameter, which provide both stability and buoyancy. The spar is secured by a taut catenary mooring system that uses anchors, chains, and mooring lines made with polyester
Reprinted with permission of International Fiber Journal
MARINE with SeaGard marine overlay finish.
“If we didn’t use such a flexible system, we would have had more damage,” Guldi said. “The storm conditions would have put a lot of strain on rigid wire, while mooring lines stretch and are meant to have dynamic movement. So this type of system was in a good position to face Katrina.”
POLYESTER ABSORB STRAIN
When it began production in 2004, Red Hawk was the second platform ever in the Gulf of Mexico to use permanent synthetic moorings with SeaGard finish as a cost-effective, high performance alternative to steel cable traditionally used in shallower waters.
“The synthetic mooring consists of high-strength polyester fiber, which provides a level of protection equiva
lent to or greater than that of steel wire rope systems, while reducing the vertical loads on the spar hull in deepwater projects,” said the federal Minerals Management Service (MMS) in approving the use of the cell spars in deepwater oil and gas projects.
And these advanced fibers made the difference against the fury of Katrina.
“The high-strength polyester fibers absorbed the strain during Hurricane Katrina,” said Whitehill’s Guldi. “The performance and quality of SeaGard finish is superior.”
In production platform applications, long-term fiber strength is critical. Performance Fibers’ polyester with SeaGard marine overlay finish plays a key role in the Red Hawk mooring system. SeaGard finish minimizes the wet yarn-to-yarn abrasion while under tension, allowing the fibers to retain maximum strength over an extended period of time.
DEEPER WATER SOLUTIONS
Increasingly, fibers with SeaGard finish are setting the industry standard as being the preferred alternative to heavy-weight steel wire in deeper water. And as oil producers delve deeper and deeper, more creative mooring designs will be required.
Polyester provides a number of benefits, including its high-strength,Mooring lines made with high-strength polyester survived the 2005 hurricanes in the U.S.
Crews move mooring lines onto specially designed reels to install them in deep waters. (All photos courtesy of Whitehill Manufacturing)
lightweight, long-term durability, and excellent product uniformity, according to Performance Fibers.
“Our portfolio of marine-grade polyester and PEN products provides solutions to mooring line engineers,” said Giangregorio. “We are constantly working to develop new fiber solutions to meet the changing offshore industry needs.”
Prior to Katrina, Red Hawk battled nature when Rita hit the Gulf Coast.
Even with a direct hit from the hurricane, it survived without damage.
Recently, a 35-foot section of the rope was removed for testing. According to Guldi, “It’s just as strong as it was before the hurricanes.”
For more information please contact Whitehill Manufacturing Tel: 1 610 494 2378 Email: rsg@whitehillmfg.com Performance Fibers Tel: 1 804 622 4078 Email: Christopher.Phillips@performancefibers.com