LEARN·CONNECT·GROW

Subsea knowledge for a deeper tomorrow.

Technical explainers built from our own animated diagrams — and a hub taking shape around them for the engineers, crews and companies who work below the waterline.

Technical explainers for the engineers, crews and companies who work below the waterline.

Join the course waitlist Start the descent

Scroll to descend · 0 m to −3,000 m

EP 06 −60 m

Everyone says SURF. Almost nobody defines it.

Before the descent, the map. Subsea Umbilicals, Risers and Flowlines — three families of line, one qualifier, and a boundary that decides which hardware belongs to the field and which belongs to the vessel above it. Start here if the rest of this page is new to you.

Animated diagram of a subsea field: umbilical, flowline and riser in three colours, running from a subsea tree to a floating host EP 06

What is SURF?

The three families the acronym names, where each one lives, and why dynamic and static are classes of service rather than kinds of pipe.

  • SURF
  • Umbilicals
  • Risers
  • Flowlines
Start here Watch →
EP 12 −90 m

Nothing arrives on its own.

Look back up at the hull you just left. An FPSO in deep water is a factory with a hotel on top, and everything it needs comes out on a schedule: materials by sea on a platform supply vessel, people by air. What comes back is decided before it goes — over the side within a limit, down a well, or back on the supply vessel’s deck as backload.

Diagram of an FPSO at the waterline with a helicopter above its deck and a platform supply vessel carrying containers, on a dashed route from the shore EP 12

Offshore Logistics

What the platform supply vessel (PSV) carries above and below deck, why people fly rather than sail, how much water forty to seventy people need, what MARPOL Annex V lets a platform discharge, what goes back to shore as backload, and the two streams that never ride the PSV at all.

  • Logistics
  • PSV
  • Helicopters
  • MARPOL
  • Backload
11:03 Watch on YouTube →
EP 02 −120 m

A pipeline that lost the seabed.

Scour, sand waves, an uneven bottom or a crossing: the support disappears and a length of pipe is left hanging. Then the current starts shedding vortices, the span vibrates at its own natural frequency, and a gap becomes a fatigue problem.

Animated cross-section of a pipeline in current, showing vortex shedding and the oscillating lift force EP 02

Free Spans in Subsea Pipelines

What a free span is, what causes one, why vortex-induced vibration matters, and how spans are assessed, inspected and corrected.

  • Pipelines
  • VIV
  • Integrity
On YouTube now Watch on YouTube →
Scene built from primitives · not to scale
THE HUB −300 m

One project, five territories.

Energy Academy Project starts as a technical channel. It is being built into a hub where subsea knowledge, the people who hold it and the companies that need it meet — one phase at a time, nothing promised before it exists.

  • SubseaSystems
  • EngineeringPractice
  • CareersPeople
  • SuppliersDirectory
  • ConsultingSpecialists
  • Now
    Free episodes

    Explainers on YouTube and LinkedIn, sources credited in every episode.

  • Next
    Newsletter & courses

    Structured learning built from the topics the audience asks for most.

  • Later
    Directory & introductions

    A curated place to find subsea suppliers, consultants and talent.

Diagram of two ladders standing on one shared first step labelled STEP 1, safety plus medical CAR 01

Subsea Careers: Two Ladders

No single offshore certificate: one first step (safety training and a medical), then two ladders — grades your employer gives you, and certificates an independent body issues after an exam. Pay figures shown are national figures, not a job offer.

  • Careers
  • BOSIET
  • ROV
  • NDT
8:47 Watch on YouTube →
Three stacked layers labelled LAW, INDUSTRY and YOUR JOB CAR 02

Offshore Safety Certificates Explained

Step one of an offshore career, country by country, in three layers: the law, the industry standard and the certificate for your job. How to renew in time and check a certificate is real. Rules change: check the official source before you pay.

  • Careers
  • BOSIET
  • GSK
  • CBSP
8:07 Watch on YouTube →
EP 01 & EP 03 −1,500 m

The column: risers and umbilicals.

Everything the field produces, and everything that controls it, travels this stretch of water. The riser on your right follows the catenary equation; the umbilical passing the camera carries the hydraulic, electrical and chemical lines that keep the wells alive.

Animated diagram of a steel lazy wave riser from an FPSO, with buoyancy modules along the arch EP 01

Deepwater Riser Configurations

Steel catenary, steel lazy wave and free-standing hybrid: how each riser is held up between the seabed and the host facility.

  • Risers
  • SCR
  • SLWR
On YouTube now Watch →
Animated cross-section of a subsea umbilical showing hydraulic steel tubes, chemical injection lines, electrical cables and fibre optics EP 03

Subsea Umbilicals & PLSV Installation

What an umbilical carries, what is inside it, the main types and accessories, and how it is installed from a pipe laying support vessel.

  • Umbilicals
  • PLSV
  • Installation
On YouTube now Watch →
Riser drawn from y = a(cosh u − 1) · horizontal run compressed for framing · not to scale
EP 04 −2,400 m

What holds a platform in place.

At this depth a fixed jacket is out of the question. The facility floats, and the lines running past you carry it back to suction pile anchors on the bottom. Which concept wins — semi-submersible, TLP, spar or FPSO — comes down to water depth, sea state, storage and the riser system it has to support.

Animated diagram of a fixed offshore platform: topsides, steel jacket and driven piles EP 04

Offshore Platforms

Fixed, jack-up, semi-submersible, TLP, spar and FPSO: how each one stays in place, and the criteria that point to one or another.

  • Platforms
  • Floaters
  • FPSO
On YouTube now Watch on YouTube →
Mooring lines and suction piles · horizontal scale compressed · not to scale
EP 11 −2,600 m

Follow one line down.

The floating facility above is held by lines like the one beside you. Follow one down: chain at the hull, polyester through most of the water column, chain again near the bottom, and an anchor that has to take the pull — dragged in, set by suction, or dropped to bury itself under its own weight. Spread or turret decides how the hull meets the weather; the risers decide how far it is allowed to move.

Diagram of an FPSO hull at the waterline held by four chain-polyester-chain mooring lines running down to torpedo piles driven into the seabed EP 11

FPSO Mooring

Spread mooring or a turret that lets the hull weathervane, the chain–polyester–chain line, catenary versus taut legs, the three anchor types (drag anchor, suction pile, torpedo pile), what the public failure records show, and why the risers set how far the vessel can move.

  • Mooring
  • FPSO
  • Turret
  • Polyester
  • Torpedo pile
11:21 Watch on YouTube →
EP 05 −2,800 m

A wall of layers, not a tube.

At the bottom of the column the line has to bend, spool onto a reel, hold hundreds of bar and live with carbon dioxide for twenty years. Steel alone does not do that, and neither does polymer. What does it is a wall of seven layers, each with a single job — and a vent path that has to stay open.

Animated cut of a flexible pipe wall in seven layers: carcass, polymer sheath, interlocked pressure armour and two counter-wound tensile armour layers EP 05

Flexible Pipe

Seven layers, each with one job; the factory that builds them; and the annulus, where a blocked vent — not fatigue — is what the Norwegian field records show behind loss of containment.

  • Flexible pipe
  • Annulus
  • SCC-CO₂
On YouTube now Watch →
EP 08 −2,900 m

One joint at a time.

A flexible line leaves the factory finished. Steel usually does not: it is welded joint by joint on deck and eased down in an S over a stinger, stood up in a near-vertical tower so it falls in a J, or welded ashore and bent plastically onto a reel. And the old rule — S-lay for shallow water, J-lay for deep — described a fleet more than a method.

Diagram of two pipelay profiles side by side: an S-lay vessel with the pipe over a stinger in an S curve, and a J-lay vessel with a near-vertical tower and the pipe falling in a J to the seabed EP 08

Rigid Pipeline Installation

The S-lay firing line, overbend, stinger and sagbend; the tensioner that straightens the pipe; J-lay and its tower; reel-lay and the welding moved ashore — and what really decides the method.

  • S-lay
  • J-lay
  • Reel-lay
  • Stinger
8:17 Watch on YouTube →
EP 09 −2,950 m

Connecting the ends.

The pipe is on the seabed, and one job is left: joining it into the system. Most subsea connections are mechanical connectors, made up by divers or, in deep water, by ROV. In shallow water the two ends can even be lifted and welded on the side of the vessel. To the US regulator, the result is an obstruction on the seabed.

Diagram of two pipeline ends lifted from the seabed to the side of a vessel and joined by a weld EP 09

Subsea Tie-ins

What the US pipeline rule asks of a tie-in, the five families of mechanical connector and how rarely they leak, and an above-water tie-in, planned at lay-down and welded on the side of the vessel.

  • Tie-in
  • Connectors
  • AWTI
  • ISO 21329
7:06 Watch on YouTube →
EP 10 −2,970 m

Pigs and traps.

Laid and tied in, the line now has to be kept clean and inspected from the inside. That is the pig’s job: a plug pushed by the flow, scraping wax or carrying sensors. The danger has always been at the trap, the pressurised door where the pig goes in and comes out. On the seabed there is no door to stand at, so there are three other ways in.

Diagram of a pig inside a pipeline, pushed by the flow, with a long plug of wax building up ahead of it EP 10

Subsea Pipeline Pigging

Why the hazard is the pig trap and not the pig, what the US offshore rule really asks of pigging, wax and the stuck pig, and the three ways a pig gets into a subsea line: a pigging loop, a downline from a vessel or a subsea launcher.

  • Pigging
  • Pig traps
  • Wax
  • Subsea launcher
10:37 Watch on YouTube →
EP 13 −2,980 m

The danger is a shutdown.

A hydrate looks like ice, but it can form well above freezing. The cold comes from the sea. The pressure does not come from the sea. It comes from inside the line: the pressure of the well and the process. When the wells are shut in, the fluid stops moving and cools towards the seabed temperature. Flow assurance keeps the fluid out of the hydrate zone with thermodynamic inhibitors, heat, lower pressure or gas dehydration. Or it slows the cooldown with insulation.

Pressure-temperature diagram with the hydrate zone shaded on the cold, high-pressure side of a curve, a warm fluid point moving towards the curve, and a thermometer marked 0 °C and at most 30 °C, under the words Above freezing EP 13

Flow Assurance

What a hydrate is and why a subsea line meets it during a shutdown, the pressure-temperature envelope, methanol versus MEG and the MEG loop, low-dosage hydrate inhibitors, insulation and heating, wax and restart, hydrates in pressure safety valves, the Deepwater Horizon cofferdam, and how Petrobras retrieved a riser with a hydrate plug estimated at more than 500 metres.

  • Flow assurance
  • Hydrates
  • Wax
  • MEG
  • Insulation
11:25 Watch on YouTube →
EP 07 −3,000 m

The box the map left grey.

Everything above this line was a line. Here is what the lines connect to: the wellhead, the tree that controls it, the rigid jumper built with bends, the manifold that gathers the wells, and the flowline that leaves — ended by a PLET, which is not a PLEM. Bought as one package, SPS, next to the SURF package the descent has followed all the way down.

Animated diagram of the seabed hardware: subsea tree, rigid jumper in an M shape, manifold, flowline and PLET, with the host greyed out above EP 07

Subsea Production System

From the wellhead through the tree, the jumper and the manifold to the flowline and the PLET that ends it — and why PLET is not PLEM.

  • SPS
  • Tree
  • Manifold
  • Jumper
  • PLET
5:08 Watch on YouTube →

−3,000 m · Seabed

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About

Precision before polish.

Energy Academy Project is a subsea and offshore education initiative run by working practitioners. Our audience works in the industry and spots a technical mistake immediately, so accuracy comes first.

Behind it are inspection, welding and installation professionals with decades of field experience on offshore and EPCI projects. We keep them unnamed while current employment ties stand — the work is signed by the project, not by individuals.

Energy education today. A stronger tomorrow.

  • The screen shows what we nameIf the narration names a component, you see that component — in real footage or in our own diagram.
  • Our own illustrationsTechnical figures from books and standards are never copied; we redraw from scratch and cite the source.
  • AI only for atmosphereGenerated imagery is limited to sea, sky and scale shots, never to close-ups of subsea hardware.
  • Sources in every episodeEach episode ends with a sources card, and we check the current edition before citing a standard.

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