Offshore Oil Platforms: Types, Anatomy, OT and Where AI Fits
An offshore oil platform is a permanent structure that produces oil and gas from wells under the sea. We built one for our conference booth: a typical four-leg fixed platform in about 300 ft of Gulf of Mexico water, assembled from the seabed up and then pulled apart so you can see what each deck does. It runs 39 seconds with no sound.
Take it apart yourself.
The same model runs in your browser. Drag to turn it, pull every system apart, and open any part for what it does and what controls it. It works on a phone.
We also built a jack-up rig and a semisubmersible the same way. See all the exhibits.
Platform or rig: which one moves?
People say "oil rig" for both, but the industry separates them. A rig drills wells and then moves on: jack-ups, semisubmersible drilling units and drillships are all mobile. A platform produces from the wells for the life of the field, often decades, and stays where it was installed. Some fixed platforms, like our model, carry their own drilling package as well, so the same structure drills and produces.
What holds a platform in place depends on the water depth. These are the main types, with depth figures from the US offshore regulator's deepwater reference1. That reference dates from 2000 and gives economic ranges, not hard limits, so treat the numbers as rough.
| Type | What holds it in place | Water depth | Examples |
|---|---|---|---|
| Fixed (jacket) | A welded steel frame pinned to the seabed by driven piles, with the decks on top | Economic up to about 1,500 ft by the 2000 reference; Offshore magazine puts it nearer 2,000 ft3 | Our model; Bullwinkle |
| Compliant tower | A narrow piled tower that flexes with wind and waves instead of resisting them | Up to about 3,000 ft | Petronius, Baldpate |
| Tension leg platform | A floating hull held down by vertical tendons anchored to the seabed | Examples only: Jolliet at 1,720 ft (1989), Auger at 2,860 ft (1994)2 | Jolliet, Auger |
| Spar | A deep floating cylinder, about 90% under water, moored to the seabed | Up to about 10,000 ft | |
| Semisubmersible | A floating hull on columns and pontoons; used to drill, or moored to produce | Not given in the reference | Our semisubmersible |
| FPSO | A ship that produces, stores and offloads oil to shuttle tankers | Relatively insensitive to depth; nearly all installed in under 3,000 ft as of 2000 | Our next exhibit |
For comparison, a jack-up is a drilling rig that stands on the seabed on legs it lowers itself, rated by its owners to about 350 to 400 ft of water. Our jack-up anatomy covers it system by system.
Twelve systems on a fixed platform
Each system in the interactive platform has its own link that opens the model on that part. The right hand column is the control layer: the operational technology (OT), meaning the controllers, sensors and safety systems that run the equipment, as opposed to the IT that runs the office.
| System | What it is | What controls or watches it |
|---|---|---|
| Pile-to-leg connection | Steel piles driven through the legs and grouted in place | Structure. Inspected, not controlled |
| Battered legs and bracing | Four legs angled outward, cross-braced | Structure. Inspected for fatigue cracking |
| Mudline | Where the jacket meets the seabed | Divers and remotely operated vehicles do the inspection |
| Export riser | The pipeline coming up a leg to the deck | Covered by the platform safety analysis, so it is part of what a shutdown isolates |
| Wellheads and christmas trees | Valve stacks on each well | Surface and subsurface safety valves that close on a sensor trip or an emergency shutdown |
| Separation vessels | Split the well stream into oil, gas and water | Pressure and level sensors feeding the safety system |
| Gas compression | Driver, compressor and coolers on one skid | Vibration and temperature monitoring |
| Process piping | The runs that tie the process together | Fire and gas detection feeding emergency shutdown |
| Drill floor | Where the drill string is made up and broken out | Blowout preventer control from the floor and from a second station |
| Derrick and monkeyboard | The tower carrying the travelling block | Drilling controls, inside limits the driller sets |
| Stairs between decks | The corridor between three stacked decks | None. Slips and falls are a people and housekeeping problem |
| Accommodation and helideck | Cabins, galley, control room, helicopter access | The control room, and the link to shore |
How a fixed platform is built
The jacket and the decks are built on land and taken out in pieces. The sequence below is the one described by the 2000 MMS reference, the Texas Section of the American Society of Civil Engineers and Offshore magazine143.
- Fabricate the jacket on shore: four, six or eight large steel tubes, braced together into a frame as tall as the water is deep.
- Tow it out on a barge. In shallow water a crane barge lifts it off. Larger jackets are slid off the barge into the sea, then upended and lowered into position.
- Drive the piles. A pile and hammer barge drives steel piles, about 7 ft across in the MMS example, through guides in the legs and several hundred feet below the mudline.
- Set the topsides. Deck modules for drilling, production and crew quarters arrive on crane barges, are lifted onto the jacket, and are connected by workers on the deck. Lifts of several thousand tons are now routine.
- Connect the pipeline to the base of the jacket and bring it up the riser to the process deck.
The biggest platforms in the Gulf
Bullwinkle, Shell's fixed platform in Green Canyon block 65, stands in 1,353 ft of water and rises 1,736 ft from the seabed to the tip of its flare boom. The jacket was installed in May 198852. When it went in it set the Gulf record for production platform water depth, beating the 1,025 ft that Shell's Cognac platform had held since 1976.
Two famous Gulf structures are often called fixed platforms but are a different type. Petronius stands in 1,754 ft of water6 and Baldpate in about 1,650 ft7, and both are compliant towers, designed to sway rather than stand rigid. Baldpate, installed by Amerada Hess in 1998, was described by its operator as the first free-standing compliant tower.
How many platforms are in the Gulf, and what happens when they stop
Industry has installed more than 7,000 platforms in US federal waters since the 1940s, nearly all in the Gulf of Mexico (now officially the Gulf of America). About 1,600 remained offshore as of June 2023, according to the Government Accountability Office citing the Interior Department, and nearly half of them are approaching or past the end of their useful life9. An earlier GAO count put Gulf structures installed from 1947 to 2014 at 7,0388. More than 600 retired jackets, 634 by the GAO count, have been turned into artificial reefs129.
The rules on removal are specific. A platform has to come out within one year after its lease ends11. On a live lease, BSEE's Gulf guidance (NTL 2018-G03) treats a platform as no longer useful once it has sat unused for five years. It then expects removal as soon as possible and within five years after that, though BSEE can vary the schedule10. In practice deadlines slip: for leases that ended between 2010 and 2022, operators missed the one-year deadline on about half of their platforms, roughly 1,300 of 2,300, by GAO's count9.
The Gulf still matters to US supply. In June 2025 the Energy Information Administration expected the Gulf to supply about 13% of US crude production in 202513. Its January 2026 outlook put Gulf output at about 1.9 million barrels a day in 2025, with 2.0 million forecast for 202614. Much of that oil now comes from deepwater floating platforms rather than fixed ones.
How many people work on an offshore platform?
It ranges from over a hundred to none. The jack-up drilling rigs we documented have beds for 108 to 160 people. Around 70 people worked on Aker BP's Ivar Aasen platform in Norway in 201829. In 2019 its control room moved onshore to Trondheim, while the rest of the crew stayed aboard3536. At the other end, Equinor's Oseberg H wellhead platform was built unmanned and is operated remotely from the Oseberg field centre3429. On a staffed platform, crews typically live aboard for a rotation and travel by helicopter.
The control layer on a platform
A survey of offshore SCADA systems done for the regulator in 2000 found two common designs: a separate programmable controller for each major unit, or one central controller on smaller and unmanned platforms. Either way the platform was monitored from shore over microwave, radio or satellite, and the local controllers kept running if that link dropped, then shut the unit down if it stayed down too long15. Newer platforms use an integrated control and safety system. Solan, west of Shetland, was designed with a separate safety system for emergency shutdown and fire and gas detection, alongside the system that runs the process, and to be controlled by satellite link from Aberdeen, 250 miles away16.
The safety logic itself is standardized. US rules incorporate API Recommended Practice 14C17, which sets out a method for analysing every piece of process equipment, deciding which safety devices protect it, and testing them18. It describes protection that acts automatically on a sensor, protection a person triggers by hand, and continuous protection from support systems such as fire detection and the emergency shutdown system. Its own explanation of why shutdown matters even on platforms that are not continuously manned is blunt: "most accidents and failures are caused by personnel." The valves down the well are covered by a companion practice, API RP 14B. Above the equipment sits the management system: the Interior Department's SEMS rule, first issued in October 2010 and strengthened by BSEE in 2013, made API RP 75 mandatory and added stop work authority for anyone on the platform1917.
Three disasters, and what they say about control
Piper Alpha, 1988. A fixed production platform in the UK North Sea exploded on July 6, 1988, and 167 people died, 165 of the 226 aboard and two rescuers; 61 survived2021. A pump was restarted with its relief valve removed for maintenance; the shift that restarted it did not know the valve was gone. The fire pumps had been switched to manual while divers were in the water, and smoke kept anyone from starting them. Neighbouring platforms kept pumping oil into the shared line for about an hour after the first explosion. The Cullen inquiry made 106 recommendations, all accepted. Almost none of it was a hardware failure. It was decisions, permissions and handoffs.
Deepwater Horizon, 2010. Often called a platform, it was a semisubmersible drilling rig. Eleven people died on April 20, 2010. The Chemical Safety Board found that the drill pipe most likely buckled inside the blowout preventer, which stopped the blind shear ram from sealing the well22. It is a drilling story, governed by different rules from the production equipment above, and we cover it with the rigs.
Taylor Energy MC-20, 2004. A fixed platform was toppled when Hurricane Ivan set off an underwater mudslide, with 28 wells connected to it24. Oil leaked for more than 14 years. Estimates of the rate disagree: BSEE put it at about 1 to 55 barrels a day in 2015, and NOAA researchers at 9 to 1082423. The lesson is the one the removal rules above try to enforce: a structure that stops producing still has wells under it.
Where AI is running on platforms today
The best documented example is BP's Plant Operations Advisor, built with Baker Hughes and live on all four of BP's operated Gulf platforms by September 2018. It watches more than 1,200 pieces of equipment and analyses about 155 million data points a day2526. It is advisory by design. It raises flags for engineers, possibly days ahead, and its stated aim was to move analysis from offshore to onshore offices, not to automate the equipment. C3 AI reported in March 2022 that Shell's predictive maintenance program covered more than 10,000 pieces of equipment worldwide with nearly 11,000 machine learning models, though the figures are not specific to platforms27. Occidental said in 2023 that it wants to add AI to its inspection cameras to detect and predict corrosion on offshore assets; we found no report that it is deployed28.
Every published case we found follows the same pattern: analytics advise, remote operators control, and the safety system stays on the platform, hardwired. We found no published account of AI running a production process on an offshore platform in closed loop. That is the gap the next wave of tools will try to cross, and it is where the governance questions start.
Ten OT devices where AI fits, and where it has to stop
The table is our read of where analytics would add most on a fixed platform, and who should own each decision. It is a map of opportunity, not a list of what any operator runs today.
| Device | Already measures | What AI could add | Who should decide |
|---|---|---|---|
| Wellhead safety valve panel | Tubing and casing pressure, valve position, test results | Spot a valve that is getting slow to close across tests, and a well whose pressure is changing | Production operator. Closing the well stays in the safety system |
| Separator level and pressure control | Levels, pressures, flows | Tune control loops and warn of slugging or foaming before it trips the train | Control room operator |
| Compressor and driver monitoring | Vibration, temperature, pressure ratio | Predict a fault days ahead, which BP says its advisor does across the equipment it watches | Rotating equipment engineer onshore, with the offshore supervisor |
| Fire and gas detectors | Gas, flame, smoke, detector health | Separate nuisance alarms from real ones and catch detectors drifting out of calibration | Offshore installation manager. Shutdown logic stays in the certified safety system |
| Corrosion probes and inspection cameras | Wall thickness, corrosion rate, images | Rank which lines to inspect first | Integrity engineer |
| Riser and pipeline instruments | Pressure, flow, cathodic protection readings | Flag a leak signature or an integrity change early | Pipeline controller and integrity engineer |
| Subsea inspection video | Diver and ROV footage of joints and the seabed | Classify footage and rank welded joints for close inspection | Structural integrity engineer |
| BOP control system and accumulators | Pressures, function times, test results | Track wear and test trends to plan maintenance | Well control engineers. AI stays out of the actuation path |
| Control system historian | Every tag the control room sees | Cut alarm floods and draft shift handover summaries | Control room operator |
| Network link to shore | Traffic between platform controls and the outside | Flag unusual traffic on the control network, the IEC 62443 view of industrial security | OT security team onshore, with the installation manager |
The higher the consequence, the further AI should sit from the actuator. We would hold any of these systems to three rules:
- Advise, then decide. The model recommends, a named person decides, and the record keeps both: what the model saw, what it advised, and what was done.
- Stay out of the safety path. Emergency shutdown, fire and gas trips and well safety valves stay in certified, independent systems. AI can watch them and help plan their maintenance. It should not be the thing that fires them or holds them off.
- Know where the model learned. A model trained on another field, a floating platform or onshore equipment is not evidence for this jacket. Validate it on the asset, and say so in writing before anyone relies on it.
The same map across the whole value chain, from well pads to refineries, with what CISA and the standards bodies say, is in AI in oil and gas.
Those rules are what ModalPoint works on. AI decision governance is about the decision, not the database: who signs off, what gets logged, and how you prove it later. The standards are moving the same way. DNV's RP-G108 applies the IEC 62443 industrial control security standard to oil and gas30. The more of a platform that is connected, the more decisions get made from its data, and the harder it is to leave unanswered who owns each one.
Where the model comes from
The geometry was traced from figures in three public domain US patents: US 4,669,918 (piles, jacket and deck in one elevation), US 6,644,893 (the four-leg jacket and its braced bays) and US 3,852,969 (battered legs and cross-bracing)313233. It is a typical mid-size Gulf platform, not a depiction of any specific platform or operator. The video is rendered frame by frame from the interactive model, so what you take apart is what you watched.
Why a decision intelligence firm built a platform
The expensive decisions in this industry get made about physical assets like this one: which vendor to trust with its data, which AI system to let near its controls, when to take it out of service. The people making those calls are rarely on the deck. We think they decide better when they can see the whole thing. An FPSO and an LNG plant are next. Heading to a show this year? Our 2026 oil and gas conference calendar has the dates.
Selling to operators? If you make the automation, controls or software that runs on structures like this, the questions above are the ones your buyers are working through. ModalPoint helps OT and automation vendors take that conversation to market: positioning, the rooms that matter at the energy conferences, and the visibility that gets you onto the shortlist. See what we do.
Sources
- MMS, Deepwater Development: A Reference Document (OCS Report 2000-015)
- MMS, Deepwater in the Gulf of Mexico: America's New Frontier (97-0004)
- Offshore, Fixed platforms remain important production facilities after more than 60 years
- Texas Section ASCE, Historic overview of US fixed offshore platforms, part III
- Offshore, Bullwinkle leading generation of platforms in US Gulf
- Offshore Technology, Petronius
- OSTI, Baldpate compliant tower installation (SPE abstract)
- GAO-16-40, offshore oil and gas decommissioning (December 2015; Gulf structures installed and removed, 1947 to 2014)
- GAO-24-106229, offshore oil and gas decommissioning (January 2024)
- BSEE, NTL 2018-G03, idle iron decommissioning guidance
- 30 CFR 250.1725, when facilities must be removed
- BSEE, Rigs to Reefs
- EIA, Today in Energy, Gulf of America crude production (June 2025)
- EIA, Today in Energy, production forecast (January 2026)
- MMS TAP 356, Survey of SCADA system technology and reliability in the offshore oil and gas industry (2000)
- Offshore, Integrated system enables oil platform to be remotely controlled (Solan, 2014)
- 30 CFR 250.198, documents incorporated by reference (API RP 14C, 14B, 75)
- API RP 14C, seventh edition (2001), as incorporated by reference
- BSEE, SEMS II fact sheet
- The Chemical Engineer, Piper Alpha: the disaster in detail
- IChemE, the Cullen report
- CSB, Deepwater Horizon blowout preventer final report
- NOAA NCCOS, MC20 oil release report
- gCaptain, Coast Guard to tackle MC20 containment
- JPT, BP and Baker Hughes go live with analytics on all Gulf platforms
- Offshore, BP deploys asset management technology on Gulf of Mexico platforms
- JPT, Shell scales predictive maintenance to 10,000 pieces of equipment
- JPT, AI is here, and it is helping with predictive maintenance in the oil field
- OE Digital, offshore platforms controlled from land
- DNV RP-G108, cyber security in the oil and gas industry based on IEC 62443
- US 4,669,918
- US 6,644,893
- US 3,852,969
- Equinor, Oseberg Vestflanken 2 and the unmanned Oseberg H platform (October 2018)
- Aker BP, Ivar Aasen now operated from Trondheim
- World Oil, Aker BP operates Ivar Aasen from Trondheim, onshore (January 2019)