Perdido Spar: How a Platform Floats in 2,450 Metres of Water

How does an oil rig stand in water deeper than skyscrapers are tall? Offshore oil platforms use three different methods to stay in place: jack-up rigs with legs for shallow water, spars that float on mooring lines for deep water, and tension-leg platforms pulled down tight by tendons. The Perdido spar floats in 2,450 metres of water—deeper than three Burj Khalifas stacked end to end. We walk through how jack-ups work to about 150 metres depth, where the legs become too heavy and long to be practical. Past that point, platforms stop standing and start floating. Spars like Perdido ride on mooring lines anchored to the seabed miles below, held in place by their own weight and the lines' tension. Tension-leg platforms, which began with Conoco's Hutton field in 1984, work the opposite way—they're so buoyant they want to rise, and are pulled down and held tight by tethers called tension legs. What the public record doesn't say is whether these methods have a depth limit beyond where Perdido already sits. The mooring lines could in principle be made longer, the hull built for deeper water. Whether there's a practical ceiling where the lines themselves become too expensive or difficult to install remains an open question. Sources — Wikipedia: Jackup rig; Wikipedia: Perdido (oil platform); Offshore Magazine: Shell's Perdido Sets Mooring Record; Wikipedia: Tension-leg platform; ETHW: Tension-Leg Platform; Wikipedia: Burj Khalifa; American Oil & Gas Historical Society: Offshore petroleum history What question about offshore oil platforms would you like answered next? #OilRig #OffshoreOilRig #RigOilWork Chapters: 0:00 How does an oil rig stand in deep water? 0:18 What is the simplest kind of oil rig? 0:41 How deep can a jack-up actually go? 1:28 What happens where the water is thousands of metres deep? 2:15 What does a rig that floats instead of stands look like? 3:03 How deep is 2,450 metres, really? 3:44 If it floats, what stops it drifting away? 4:41 Is a spar the only way to float and stay still? 5:38 When was this idea first tried, and did it work? 6:35 How did offshore drilling get this far from shore? 7:45 Is there a depth even these designs can't reach? 8:34 Who actually works on these structures? 9:08 So how does an oil rig actually stand in deep water? Narrated by an AI voice. Pictures are AI-generated illustrations unless credited above.