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All photos and illustrations by Jesper Berggreen

Fossil Fuels

The Last Job For A Drillling Rig Before It Can Become A Spaceport

To construct any meaningful title for this article was quite the challenge, because what I am about to describe to you has forced me to bend my mind in ways it has not been bent before, so in this context it was very convenient to be able mix the concept of oil drilling and space travel.

My good colleges Johnna Crider and Jennifer Sensiba here at CleanTechnica did a great job in following up on the news from Elon Musk last year that SpaceX would use decommissioned oil rigs to launch and land its heavy duty Starships: “SpaceX is building floating, superheavy-class spaceports for Mars, moon & hypersonic travel around Earth,” Elon wrote on Twitter.

Johnna provided a great overview in January, and Jennifer covered it in more detail shortly after. Recently I had the incredible good fortune to be invited on a tour of one of the world’s largest drilling rigs, and this is my chance to try to give you a sense of just how massive these structures are. It’s truly mind-boggling. All photos are down below.

Welcome On Board The Maersk Interceptor

The Maersk Interceptor is an ultra harsh environment jack-up drilling rig built in 2013 based on the prototype Maersk Innovator that happened to be in dock right beside the Interceptor at this time, which would prove very convenient for reasons I will explain below. Maersk has about a dozen of these jack-up type rigs, which are among the largest in the world.

The difference between an oil rig and a drilling rig is that the drilling rig just drills and leaves the site again when it’s done. Oil rigs can be just for pumping oil, but can often do both the drilling and pumping. Maersk had one of these dual-purpose rigs until recently, but this last piece of oil extraction equipment was recently sold just a few years after Maersk sold its oil division to Total for $7.45 billion. Offshore rigs don’t come cheap — their costs run up in the hundreds of millions dollar range, depending on size and functionality.

Maersk has now begun the work of decommissioning hundreds of oil wells around the world, a job of extracting equipment and capping bore holes that will keep them busy for at least a couple of decades. So in this sense, the drilling business is still highly lucrative and will be many years after the last drop of oil has been pumped up. Up until this tour on a drilling rig I had no idea how much work goes into removing the equipment below and on the sea bed. But first, the drilling machine has to be up for the job.

The World’s Largest Powertool

Walking around on, and in, this drilling rig can best be described as being like an ant inside a vending machine. Usually when you press a button to get your coffee or snack, you just stand there listening to the whirring noises of tiny levers and grabbers and pumps and push rods that eventually serves you something overpriced that you probably regret the instant you taste it. But imagine being an ant inside that machine with structures towering dizzying up above you, with motors and joint and pulleys all over the place so large that you can’t even make out that they are actual motors and joint and pulleys.

It surprised me how hard it was to get the proportions right and understand what I was looking at when being shown around. This is why it was so useful to have a nearly identical copy of the Maersk Interceptor in dock right next to it, the Maersk Innovator, built a few years prior. This way I could look at some very big structure right next to me and glance over at the copy next to us and see it in its context.

The Maersk Interceptor has the model name “MSC CJ70-X150 MD” and all I remember from this name is that the “70” stands for the distance between each of the 3 legs it stands on, in meters. Yes, so this is a triangular platform 70 meters (230 feet) on each side suspended within three 200-meter (656 feet) tall legs. Ok, so let’s break it down into concepts, not only to understand what is needed for this rig’s primary function, but also what you would have to refurbish should you have the desire to buy one and convert it into a spaceport. Spoiler alert: Don’t. Build a new one, it’s probably cheaper.

The Platform

The rig’s main platform is a giant 3-sided hollow structure measuring well over 70 meters (230 feet) along each side and 14 meters (46 feet) tall, with a “hole” in each corner in which the legs slide vertically. This main rig hull floats when the 3 legs are pulled up and is towed around the world, and it weighs 28,000 metric tonnes in empty transport mode. When in place and in operation, it can reach a total weight of 40,000 tonnes fully loaded with equipment.

It also has 3 separate ballast tanks at each corner that can take in 11,000 tonnes of sea water each. This is needed when the legs are to be lowered and placed firmly onto the sea bed. Our guide told us that the most difficult situation this platform had experienced was finding solid bedrock out of the Nile Delta in the Mediterranean sea, where the legs went through 30 meters (98 feet) of muddy seabed before getting a firm stand. It took 4 days of throbbing each leg a few feet one at a time.

The inside of the platform itself is so voluminous that it looks like a regular huge factory you would find on land, only, it floats — or stands on 3 legs — and has no windows. The amount of things going on inside the platform is impossible to summarize, so I will just mention a few.

The main power source of the rig is located in 2 separate locations and configured as 4 independent huge diesel engines directly connected to each of their own 3 MW electric generators. But there are many more diesel generators scattered all over the rig where heavy duty hydraulic power is needed. Less demanding hydraulics (less than 2,500 hp) is powered by electric motors.

A central function of the inside of the platform is a giant pump that is used in the special closed loop of slurry that is pumped down in the bore hole at up to 1,000 bar (14,500 psi) and through sleeved tubing returned back up and passed through enormous filters before being reused. The grain size in the drilling slurry is measured in microns. The whole system is named Zero Discharge meaning that the reflux of bore hole debris is treated on board, shipped to shore and thus not dumped on the seafloor. The fine grained slurry is recycled continuously in the closed loop.

As you can imagine, these systems take up a lot of space, but there is still room for giant warehouses with spare parts, tubing, tanks, every commodity you can imagine, and a myriad of workshops, ranging from big ones for welding and small ones for electronics.

The Legs

Each of the 3 legs that supports the platform are themselves constructed of 3 tubes with giant teeth that fit into giant gears that raise or lower the platform. The machinery that makes this all work is really heavy duty. I mean, you can’t really fathom the scope without standing right in front of it. Here are some numbers: 8 electric hydraulic motors are attached to each of these 3 tubes, so that’s 8 x 3 x 3 = 72 motors total for the whole rig. Each one of these 72 motors weigh 16 metric tonnes and has a power output of approximately 2,000 horsepower. In other words, when the platform is slowly rising on its legs, up to 144,000 horsepower is at work, although often only one leg moves a few feet at a time. By the way, these motors are the reason this platform is in dock. All 72 jack-up motors are being refurbished after 7 years of work. It will be another year before this task is completed.

The Drill

The drill assembly is an absolute engineering marvel. It’s mobile on the platform itself. When drilling is performed, the 70-meter tall drilling tower is moved up to 20 meters over the edge of the platform. The tower is attached to a giant box, some 15 meters tall in itself, that can move in a x-y coordinate, making it possible to drill up to 8 separate bore holes even though the rig itself is stationary. It’s like a giant 3D-printer! The box and tower combined weigh 11,000 metric tonnes, and it all moves along on unreal large bearings.

When you walk around inside the drilling assembly, it’s just like another huge factory filled with equipment and parts such as the tubes that are fitted in the bore hole. If you have ever wondered how these things can drill straight down a few miles and then turn and drill another few miles horizontally, it’s simple math: every tube piece is 7 meters long and can tilt 1 degree each at the joints, which in theory let’s you go full circle in 7 x 360 = 2520 meters (1.6 miles).

One crucial item in this drilling assembly box is the emergency top valve — you know, the one that failed on the Deepwater Horizon rig. Painted white, it is suspended from the ceiling of the box. It weighs 100 metric tonnes and consist of so many layers of valves and features that it is impossible to understand for the casual visitor (no photos allowed btw). It just hangs there, as light as a feather, ready to be deployed in minutes and dumped on a runaway bore hole. Luckily, this one has never been used.

The drill itself is suspended from the top of the drilling tower and is powered by an electric system with 2,300 horsepower. The single hook crane can carry 910 tonnes.

The Facilities

Located in the opposite corner from the drill, snugly angled around one of the rig’s legs, is what looks like a dual winged 5-story hotel with a giant helicopter pad attached on top to its side. One wing contains the bridge, control rooms, offices, meeting rooms, galley, and rooms for leisure activities like fitness, games, and movie theater. The other wing is accommodation for up 140 crew members at a time, most of which are single rooms. At full time operation this rig has a running cost of about $1 million a month.

Some Takeaways

Unfortunately, this topic of offshore extraction of fossil fuel just had a new disaster written on the list: “The ocean is on fire” in the Gulf of Mexico, tweeted by Brian Kahn, the managing editor at Earther on July 2nd. Johnna Crider has the story here. My goodness, let’s put a lid on these things already!

However, let’s not forget that civilization got to this point with the help of fossil fuels. Yes, we need to get off fossil fuels as fast as possible, and yes, there is a lot of doubt whether those who thrive from pumping up this stuff is all that eager to let go of their golden goose, but we don’t need global turmoil in this endeavor. It’s a transition, and everybody is needed to finish the job.

So, can rigs like the Maersk Interceptor really be used as spaceports in the future? It’s fun to think of SpaceX Starship for a size comparison: The booster is 70 meters (230 feet) tall and the Starship itself is 50 meters (164 feet) tall, so yes, it will fit nicely on there, and there are towers and cranes and stuff at hand.

However, from what I’ve now seen, using an old drilling rig as platform will need so much refurbishing that I can’t help thinking of the development of the original Tesla Roadster. Elon Musk has stated that using the Lotus Elise as a platform was a waste of money and time. Start from scratch and do it right. That said, there is a lot of cool engineering going on in the rig business, and the functionality of the hardware itself can prove very useful for a large scale offshore space industry.

But what about the fuel for the rockets? Well, SpaceX has now proven the methane-fueled Raptor engine is viable, and it is possible to produce methane from water, carbon dioxide, and electricity. Water is not a problem offshore, providing desalination can be achieved in needed amounts, and carbon dioxide is in the air, and at sea the surface area could maybe enable enough solar to produce methane right there at the spaceport itself. Imagine Starships taking off and landing at offshore spaceports fueled essentially by nothing but the sun.

Anyway, I have given you a rare glimpse of the inner mechanics of a traditional drilling rig, so what do you think? Are future spaceports going to be offshore, or is it easier to keep them on land?

My own rough schematics to better get an overview of the rig. A SpaceX Starship is exactly the same height as the drilling assembly at 70 meters. Left: seen from above. Right: seen from the side.

 

One set of 8 jack-up motors weighing 16 metric tonnes each. The rig is in dock to have these 72 total motors serviced

 

About to board the rig. The drilling tower 70 meters tall. The legs 200 meters tall. Here they are about 20 meters under water too. Total weight 28,000 metric tonnes dry and 40,000 tonnes maximum in operation

 

A closer look at the outside of the hull, 14 meters tall by itself. In the background the future of deep sea offshore energy: a floating wind turbine

 

Close up on the “hand brake” on one rod on one leg. Slides in place to ease the strain on the 72 jack-up motors

 

A look inside one leg. Up above the “hand brake” the back bearings of the huge jack-up motor gears is seen

 

View from the helipad onto the rig

 

View from the helipad onto the neighboring, almost identical, rig for a better perspective

 

“The box” onto which the drilling tower is mounted weighing a total of 10,000 metric tonnes. Note the giant cable guide underneath that, illustrating the freedom of movement

 

Storage area for pipes on top of the drilling assembly to easily grab and place into the tower

 

A look inside the drilling tower. No manual work here, everything is controlled from inside the cage on the right

 

All photos and illustrations by Jesper Berggreen

 
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Written By

Jesper had his perspective on the world expanded vastly after having attended primary school in rural Africa in the early 1980s. And while educated a computer programmer and laboratory technician, working with computers and lab-robots at the institute of forensic medicine in Aarhus, Denmark, he never forgets what life is like having nothing. Thus it became obvious for him that technological advancement is necessary for the prosperity of all humankind, sharing this one vessel we call planet earth. However, technology has to be smart, clean, sustainable, widely accessible, and democratic in order to change the world for the better. Writing about clean energy, electric transportation, energy poverty, and related issues, he gets the message through to anyone who wants to know better. Jesper is founder of Lifelike.dk and a long-term investor in Tesla, Ørsted, and Vestas.

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