Assembling one of the deepest offshore hubs

Perdido’s hull and platform weigh around 55,000 tonnes — the decks alone are as big as two football fields — and it is moored in about 2,450 metres (8,000 feet) of water. The scale of the project demanded international expertise, with equipment brought in from around the world.

Take a pre-construction tour of the Perdido spar

Read the transcript

Title: Perdido spar – Take a pre-construction tour – from YouTube

Duration: 4:05 minutes

Description:

Animated video with narration of a pre-construction tour of the Perdido spar in the Gulf of Mexico

Perdido spar – Take a pre-construction tour – from YouTube Transcript

[Animated sequence]

Fly-around of the Perdido platform in the Gulf of Mexico.

[Narration]

The Perdido spar is more than a mile and a half above the Alaminos Canyon seabed in the Gulf of Mexico. It is challenged by rugged seafloor terrain, highly faulted, low pressure reservoirs. It will be the deepest spar in the world – 7,817 feet, 2,382 meters – with production from the deepest subsea well in the world, Tobago – 9,627 feet, 2,934 meters.

[Animated sequence]

Shot of the earth’s surface. There are red lines rising up from the seabed indicating the well paths.

[Narration]

As we move beneath the earth’s surface, below we see the well paths in red at the South West cluster site. In addition to these locations, there are two more remote sites six to nine miles away, Silvertip and Tobago.

[Animated sequence]

Underwater shot showing the Silvertip and Tobago cluster sites.

[Narration]

The flowline sleds, shown with a green or blue line, connect the South West cluster Silvertip and Tobago sites to a manifold. The manifolds then tie into the subsea boosting system and case-on risers that will carry the hydrocarbons up to the spar.

[Animated sequence]

Shot of the cluster site. The flowline sleds are shown in yellow and circled in white. Then the subsea boosting system is shown circled in white.

[Narration]

This is the top of the subsea boosting system.

[Animated sequence]

A more detailed shot is shown of the subsea boosting system, including the manifolds and case-on risers.

[Narration]

We’re flying by the soft tank now. The bottom of the soft tank is 500 feet below the surface of the water. This is the area where the ballast is loaded. It provides the low center of gravity necessary to keep the spar upright.

[Animated sequence]

Shot of the subsea soft tank. The bottom of the soft tank is circled in white.

[Narration]

This is the west side of the platform, where you can see the turbine generators and waste heat recovery units, as well as two of the 86-man life craft.

[Animated sequence]

At the sea surface, zooming in on the Perdido platform, in the bottom right the turbine generators and waste heat recovery units are shown circled in white. Then, in the bottom left, the life craft are shown circled in white.

[Narration]

Let’s rotate around to the south side. In the lower right is one of the major safety advances that is incorporated in the platform, the 24-man fast recovery craft. This size was chosen to be able to pick up the entire complement of an S-92 helicopter, which will be used to crew change the platform.

[Animated sequence]

Rotating around to the south side of the Perdido platform, in the bottom right, the fast recovery craft is shown circled in white.

[Narration]

As we come to the right, we are at the east side of the platform. The crimped metal building is the workshop and just to the right of there is another important safety feature of the Perdido platform. This is the edge of the blast wall. This feature, combined with blast-resistant quarters, protects all the production buildings, quarters and temporary refuge.

[Animated sequence]

Rotating around to the east side of the Perdido platform, on the left the workshop is shown circled in white, followed by the blast wall, also circled in white.

[Narration]

Here is an end view of the two booster gas compressors. They are necessary to take the very low pressure gas and get it to export pipeline pressure necessary to make the long distance tieback to existing pipeline infrastructure.

[Animated sequence]

Rotating around the Perdido platform, the two booster gas compressors are shown circled in white.

[Narration]

This is the spar deck, 50 feet off of the water. The man is six feet tall and holding a two-meter stick.

[Animated sequence]

Zooming out from the spar deck. On the deck, a man in blue is shown holding a white stick, circled in white.

[Narration]

We are now flying down the center well of the hard tank. The six blue risers in the center include the drilling riser and five production risers.

[Animated sequence]

Zooming into the well of the hard tank, we can see an opening with red pipes on the sides. Once inside the tank, there are several blue risers.

[Narration]

We are back up to the helicopter fly-around. This is what the pilots will see on approach to the platform, where they will be welcomed by the largest helideck in the Gulf of Mexico. This specially designed, aluminum deck is large enough for two S-92 helicopters.

[Animated sequence]

Fly-around of the Perdido platform. The yellow helideck on the platform is shown and circled in white. Fly-around of the platform continues. Static overhead shot of the Perdido platform.

[Narration]

The Perdido platform is the first commercial production from the Paleogene. It will be the deepest spar in the world, with production from the deepest subsea well in the world.

[Text displays]

Black background with very small white text – disclaimer.

The hull, or spar, was built in Pori, Finland, using steel from a mill 500 kilometres (310 miles) away. It is nearly as tall as the Eiffel Tower and took more than two million working hours to build with no time lost due to injury, a record for such a construction project.

A giant barge shipped the 22,000-tonne spar on a 13,200-kilometre (8,200-mile) journey from the Baltic Sea to Ingelside, Texas, in the Gulf of Mexico. Here the barge was flooded to partially submerge it, allowing the spar to float on the water. Two tugboats towed it to its final home in the Alaminos Canyon area of the Gulf of Mexico, 320 kilometres (199 miles) from the nearest supply port at Galveston, Texas.

Working through hurricane season, a team raced to secure the giant floating spar to the seabed. To rotate it from a horizontal to a vertical floating position, they pumped water through hoses attached to the top of the spar, gradually filling tanks near the bottom. It took more than 20 hours to finally get it upright. They attached nine mooring lines and anchored the spar to piles in the seafloor, then evacuated before hurricane Gustav hit in early September, 2008.

Hurricane resistance

Buster Stewart was the drilling foreman on Noble Clyde Boudreaux

Read the transcript

Title: Shell Perdido - Buster Stewart, Noble Clyde Boudreaux drilling foreman

Duration: 2:37 minutes

Description:

Buster Stewart, drilling foreman on the Noble Clyde Boudreaux oil rig talking about working at Shell and the people.

Shell Perdido - Buster Stewart, Noble Clyde Boudreaux drilling foreman Transcript.

[Background music plays]

Upbeat guitar music.

[Animated sequence]

Shell oil tanker driving by and then a flashing montage of people who work at shell which multiplies until the whole screen is made up of tiny shots of different workers.

[Text displays]

Shell People.

[Buster Stewart]

Drilling Foreman, Shell Upstream Americas

[Buster Stewart]

My job is a drilling foreman, I work for Shell and we’re on the Clyde Boudreaux. This rig is kind of unique, it has some super large mud pumps, has a lot of deck space, tremendous deck load. It has two derricks so we run a concurrent activity. We can do simultaneous operations. We’re able to actually run casing with our aft one while we’re drilling the whole with the forward one. So we’re drilling a hole over here that we’re running casing for over here, we run it and we seam [?] in it, and that’s done, then we start over again. It’s pretty impressive, the dual activity that cuts our time in half. We’re never in a hurry, we work safe. If we have to stop we stop, that’s not a big deal but we want to keep moving, make every second count. And everybody wants to see the ROV when they come that’s probably the neatest thing on the rig.

[Video Footage]

Buster Stewart wearing protective clothing and headgear with Shell logo talking face on to camera in interior of oil rig. Various shots of interior of oil rig. Shots of derricks at night. Shots of lots of pipes stacked up. Pipes moving along. Men sitting in office seen from outside. Shots of dials and monitors. Worker checking monitors and dials. Buster talking face on to camera. Shots of different parts of oil rig. Men in hard hats walking towards and examining some machinery.

[Buster Stewart]

And you’ve seen it on Discovery Channel and History channel, you know they go look at the Titanic and all, we use them every day. We’re drilling in about you know 9/10,000 foot of water. We can’t see what’s going on down there so the ROV does it for us. It has manipulator arms that can retrieve tools and adjust things for us; it’s really a wonderful piece of equipment. And the guys that operate it are phenomenal, overgrown Nintendo players. It has a 200 man living quarter which is probably right up there with the largest. There may be some bigger, I’ve never been on one bigger. We have an 82 person cinema, 82 person galley, there’s a weight room, a gym, it’s really nice. It’s got all the comforts of a hotel I guess you could say.

[Video Footage]

Underwater shot of ROV in use. Buster in protective clothing and hard hat talking face on to camera. Various views of different machinery. Computer generated view of ROV showing how the arms can be manipulated and adjustments can be made. Man sitting in front of monitor operating the ROV. Aerial view showing scope of rig. Shot of scaffolding with Noble sign on it. Different shots of rig. Shot of men standing on high platform against night sky.

[Buster Stewart]

I’ve actually rode a hurricane out, rode it out on a rig one time. It really wasn’t that bad, believe it or not, and I’ve been involved in two rigs that blew and that’s kind of a scary feeling. There was so much destruction with Katrina they actually went back to the drawing board after this rig had started being built and added eight more mooring lines, so there’s 16 winches on here so we should be able to withstand anything out there. It will be interesting to see out it fares, so I think it will do real good. The most important thing about any drilling rig and I guess any company, any organization is the people and you’ll never, ever find a closer knit group of people than you will on a drilling rig; it’s 24 hours a day you’re right here with these people. And that’s what’s makes… the earn is wonderful but it’s nothing without the people.

[Video Footage]

Computer monitor showing weather conditions. Man points to the screen where hurricane took place. Exterior shot of oil rig. Buster in protective clothing and headgear with Shell logo talking face on to camera. Misty faraway shot of rig, zooming in to much closer shot. Buster in protective clothing and headgear with Shell logo talking face on to camera. Workers, some in protective clothing and headgear sit in front of monitors and dials. One point to something. Exterior shot of group of workers in protective clothing and headgear. Derricks in background. Buster talking face on to camera. Fades to illegible writing on black background.

Iron ore ballast at the bottom of the spar helps keep it upright and stable. As a precaution ahead of hurricanes the spar can increase ballast by adding water to internal tanks. That means it won’t move up and down much more than a few metres with the waves, reducing the tug on the tubes that bring oil and gas to the surface from the seabed.

Perdido’s 22,000-tonne hull was designed to withstand the most powerful storms, the type expected to occur only once in 1,000 years. To prevent damage to mooring lines from scraping on the seafloor and against the spar, the 25-centimetre-thick (10-inch) polyester lines have a 300-metre (984-foot) section of chain at the top and bottom. Winches on the platform make it possible to move the spar into the most secure position before a hurricane hits.

Assembling a perfect puzzle

The platform’s three decks — or topsides — support oil and gas processing units, living quarters for about 170 people and a drilling rig. Yet all that equipment had to be light enough so that special floating cranes could lift the assembled topsides onto the upright spar. “The deck had to go on a diet,” said Kurt Shallenberger, who led the topsides project. By weighing all materials and every piece of equipment — including more than 21 kilometres (13 miles) of pipes — the team achieved a topsides weight just one tonne over the exact target.

“The Perdido facility is like a gigantic jigsaw puzzle,” said Shallenberger. “There’s lots of pieces and parts that all have to work, that all have to be safe, and everyone’s got to agree how they fit together.”

Laser-aided measurements

Temperature differences between Finland and Texas posed another challenge to assembly, as the steel components built in the cold of northern Europe expand in the heat of the Gulf of Mexico.

A team of experts calculated dimensions for components on the deck and hull using advanced computer modelling. This allowed for potential expansion, as well as flexing of steel when cranes lifted the topsides. Computer-guided lasers marked out the measurements during construction to ensure everything fit perfectly. In March 2009, cranes lowered the 9,500-tonne topsides onto four posts on the spar, slotting it into position exactly and setting a record for the heaviest topside lift in the USA.