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The most famous oil platforms in the world

By Arthur More · professional saturation diver · 18 August 2026

Published 15 July 2026 · 12 min read · 2,344 words

In brief

The most famous oil platforms in the world are famous for their size, their depth or their history: Troll A, Thunder Horse, Perdido, Petronius, Hibernia, Prelude FLNG, Berkut and Piper Alpha. Each poses a different underwater maintenance challenge, split between commercial divers in shallow water and ROVs in the depths.

The offshore sector is full of enormous structures, but only a few have earned a name for themselves outside the trade. Some for their size, others for the depth at which they operate, and a few for what happened on them. For anyone in commercial diving, that fame also has a practical reading: each type of structure implies a different inspection and maintenance regime.

This roundup brings together eight recognisable installations, with verifiable data on operator, location and configuration, and explains what each one means from the point of view of underwater work. If you're after a broader view of the installation landscape, there's more context in the section on plataformas.

What makes a platform iconic

An offshore installation's fame is almost never a matter of production. The fields moving the most barrels are usually anonymous. What makes a platform memorable is that it breaks a technical limit, that it solves a problem no one had solved before, or that its history changed how the rest of the sector works.

In practice, the criteria that keep coming up are these:

Scale of construction: concrete or steel structures that break records for weight, height or displacement.
Water depth: installations that opened the way into deep and ultra-deep water.
Extreme environmental conditions: ice, icebergs, typhoons or seas with waves over fifteen metres.
Conceptual innovation: flexible towers, direct-access vertical spars, floating liquefaction plants.
Regulatory impact: accidents that forced a change in regulatory regime across the whole industry.

That last point deserves attention. A large share of the procedures any offshore diving team applies today (permits to work, energy isolation, management of change) came out of investigations into specific disasters. The sector's technical history is, to a large extent, a history of expensive lessons learned.

Troll A: Norwegian concrete resting on a 300-metre bottom

Troll A is the inevitable reference point when talking about gravity-based platforms. It's a Condeep-type reinforced concrete structure installed in the Troll field, off Norway's west coast, and operated by Equinor. Its four legs run down to the seabed, at 303 metres depth, and the installation's total height reaches 472 metres.

The leg walls are over a metre thick and were poured continuously, an operation that went on for months. The structure was towed to its site in 1995, in a manoeuvre broadcast live on television in Norway: it was, and still is, one of the largest objects ever moved by human beings.

Troll A isn't alone in that family. In the same North Sea, Gullfaks C is another concrete Condeep, in production since November 1989 in 216 metres of water, whose operating life has been extended by the Norwegian authority to mid-2036. That pattern — structures from the eighties and nineties still in service decades later — explains a large share of the current workload for saturation diving in the North Sea.

For underwater work, a gravity-based platform sets specific tasks: visual and ultrasonic inspection of the concrete, monitoring of cathodic protection, review of riser and conductor connections, cleaning of marine growth, and verification of seabed contact. Much of it is done with ROVs, but interventions needing fine manipulation still fall to saturation divers.

Thunder Horse: the Gulf of Mexico semi-submersible

Thunder Horse PDQ is a semi-submersible production, drilling and accommodation platform sitting over the field of the same name, in the Mississippi Canyon area of the Gulf of Mexico, about 240 kilometres south-east of New Orleans. It's operated by BP with a 75% stake, alongside ExxonMobil. It's moored in roughly 1,840 metres of water and its design processing capacity is around 250,000 barrels a day.

Its fame didn't come from size alone. In July 2005, after Hurricane Dennis passed, the platform was found alarmingly listed before it had even come on production. The cause was a ballast system failure made worse by a valve installed backwards. Welding problems in the subsea pipework followed on top of that. First production was delayed until June 2008.

That history turned Thunder Horse into a case study on subsea system integrity and manufacturing quality control. From a diving point of view, it's also an example of the operating limit: at almost two kilometres depth, no human intervention is possible. All maintenance on the subsea field is carried out with work-class ROVs deployed from support vessels.

Perdido: the frontier of ultra-deep water

Perdido, from Shell is a direct-access vertical spar installed in the Alaminos Canyon 857 block, at the western edge of the Gulf of Mexico. It's moored in about 2,438 metres of water and came on production in 2010, beating the production-installation depth record by a wide margin.

It works as a regional hub: it gathers production from the Great White, Silvertip and Tobago fields, spread across several blocks in the area. The spar configuration allows the drilling and completion equipment to sit directly over the wells, something unusual at those depths.

Perdido is a good illustration of a structural shift in the sector: the deeper you go, the fewer divers and the more robotics. In the ultra-deep band, saturation diving is out of the picture entirely and the work moves to ROVs, diverless intervention tools, and subsea connection systems designed to be operated remotely. If you want to see how that work is spread geographically, the section on where saturation diving work happens breaks it down region by region.

Petronius and Hibernia: two structural records of the Atlantic

Petronius, the compliant tower

Petronius is a compliant tower operated by Chevron in the Gulf of Mexico, about 210 kilometres east-south-east of New Orleans. It was built between 1997 and 2000 and stands about 640 metres from the seabed to the tip of the flare boom, which for years put it in the running for tallest freestanding structure in the world.

The compliant tower concept is the key to its technical interest: instead of rigidly resisting waves and current, the structure is designed to sway. That flexibility reduces loads and allows depths a conventional jacket couldn't handle, but it demands rigorous fatigue monitoring on the welded joints, with periodic underwater inspections.

Hibernia, the iceberg-resistant platform

Hibernia is a concrete gravity-based structure installed on the Grand Banks of Newfoundland, about 315 kilometres south-east of St. John's, in 80 metres of water. It was the first platform designed specifically to withstand the impact of drifting icebergs: its outer wall has sixteen concrete teeth built to absorb that energy.

The cylindrical caisson also includes crude storage capacity, on the order of 1.3 million barrels, for loading shuttle tankers. The area is known as Iceberg Alley for the passage of icebergs breaking off Greenland's glaciers. Working underwater there means short weather windows, very cold water and tightly planned inspection tasks.

Prelude FLNG and Berkut: floating gas and Pacific ice

Prelude FLNG

Prelude is Shell's floating liquefied natural gas installation, in the Browse Basin, off the coast of Western Australia. At 488 metres long and 74 metres wide, it's the largest floating structure built to date. It's moored in about 250 metres of water and started production in December 2018, with liquefaction capacity of around 3.6 million tonnes a year.

Its conceptual interest lies in bringing a complete process plant to the field instead of laying a pipeline ashore. The turret mooring system and its links to the subsea wells generate an ongoing inspection programme, with dives and ROV work on mooring lines, flexible risers and connection structures.

Berkut

Berkut, on the Sakhalin-1 project, is an ice-resistant fixed platform installed on the Arkutun-Dagi field, in the Sea of Okhotsk, developed by Rosneft alongside ExxonMobil. It was designed for severe subarctic conditions: waves up to 18 metres, pressure from ice floes up to two metres thick, and temperatures down to 44 degrees below zero. First production was reached in January 2015.

In environments like these, the diving window shrinks to the ice-free months and surface logistics dictate the whole operation. Planning a campaign looks more like a polar expedition than a conventional maintenance contract.

Piper Alpha: the platform that changed offshore safety

On 6 July 1988, a hydrocarbon leak caused an explosion and fire that destroyed the Piper Alpha platform, in the British sector of the North Sea. 167 people died and 61 survived. It remains the worst accident in the history of the offshore industry.

The subsequent investigation found that a condensate pump had been taken out of service for maintenance and that its safety valve had been replaced with a blank flange. The night shift, unaware of the situation, started the pump. The underlying failure wasn't mechanical but organisational: a permit-to-work system that was misunderstood and applied inconsistently by the operator.

The public inquiry led by Lord Cullen, whose report was published in November 1990, made 106 recommendations. Out of them came the British safety case regime, formalised in the Offshore Installations (Safety Case) Regulations of 1992, which requires every installation to demonstrate in writing that it has identified and controls its risks.

For a commercial diver, Piper Alpha's legacy is everyday and very concrete:

Formal permits to work and written handover of information between shifts.
Isolation and lockout of energy sources before any underwater intervention.
Clear authority to stop work in the face of an unsafe condition.
Auditable drills and evacuation plans on every installation.
Documented management of changes from the approved procedure.

What role divers and ROVs play on these structures

None of these installations maintains itself. Below the waterline there's structure, conductors, risers, mooring lines, anodes, cathodic protection systems and subsea equipment that need periodic inspection and occasional repair. The split between diver and machine mainly depends on depth.

In the shallow to medium band, up to around 150 metres and in some cases a bit more, saturation diving remains the most effective tool when it comes to welding, cutting, tightening flanges, fitting clamps, or carrying out inspections that need touch and judgement. The section on what a saturation diver is explains how that way of working functions.

Below that depth, the work passes entirely to work-class ROVs and tools designed to be operated remotely. Perdido and Thunder Horse are clear examples: there are no divers there, only ROV pilots, tooling technicians and subsea intervention supervisors.

The usual tasks on these structures fall into these groups:

Visual structural inspection and NDT on critical joints.
Measuring cathodic protection potentials and replacing anodes.
Cleaning marine fouling off legs, conductors and bracing members.
Inspecting mooring lines and anchoring components on floating installations.
Structural repairs: hyperbaric welding, clamps, reinforcement and patching.
Working on subsea equipment: swapping out modules, connecting control lines and operating valves.

The result is a job market with two clearly separate tracks. Commercial diving keeps a stable demand in shallow and medium water, while growth in ultra-deep water translates into ROV and remote intervention jobs. Anyone considering entering the sector does well to understand that split before choosing training; the section on how to become a commercial diver sets out the usual routes in.

These eight installations don't cover every case, but they span the range well: concrete, steel, floating, fixed, ice, ultra-deep water, and the memory of an accident that rewrote the rules. Knowing them is a quick way to understand why underwater work isn't the same in the North Sea, in the Gulf of Mexico, or in the Sea of Okhotsk.

Frequently asked questions

Which is the most famous oil platform in the world?

It depends on the criterion. For general recognition, Troll A usually tops the lists for its 472-metre height and its concrete base resting at 303 metres. For historical relevance, the most cited is Piper Alpha: the 1988 accident and Lord Cullen's inquiry transformed offshore safety regulation in the United Kingdom and, by extension, across the rest of the sector.

Do people dive on ultra-deep-water platforms?

No. On installations like Perdido or Thunder Horse, in water depths of between 1,800 and 2,400 metres, direct human intervention isn't feasible. All subsea maintenance is carried out with work-class ROVs and remotely operated tools from support vessels. Saturation diving is concentrated at much shallower depths, normally below 150 metres.

What did Piper Alpha change in offshore safety?

The public inquiry led by Lord Cullen, published in November 1990, issued 106 recommendations. The most influential gave rise to the British safety case regime, set out in the Offshore Installations (Safety Case) Regulations of 1992, which requires every installation to demonstrate in writing that it identifies and controls its risks. It also strengthened permit-to-work systems and the handover of information between shifts.

Which is the tallest oil platform?

Petronius, Chevron's compliant tower in the Gulf of Mexico, stands about 640 metres from the seabed to the tip of the flare boom, putting it among the tallest freestanding structures ever built. Troll A reaches 472 metres in total height. Comparisons vary depending on whether you measure from the seabed, from the water surface, or including the flare.

What underwater work is done on a concrete platform?

Concrete gravity-based structures, such as Troll A, Gullfaks C or Hibernia, need inspection of the concrete and its reinforcement, monitoring of the cathodic protection system, verification of seabed contact and the condition of the ballast cells, cleaning of marine growth, and review of conductors and risers. Inspection combines ROV work with diver work when fine manipulation is needed.

Published 18 August 2026 · By Arthur More, professional saturation diver

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