What is a semi-submersible drilling rig?
What is a semi-submersible drilling rig?
2.2 Semi-Submersibles. Semi-submersibles are the choice for drilling from a floating position, due to the deep water depths. Semi-submersible (“semi”) rigs float like a ship while being towed into position, where their pontoons can then be flooded, partially submerging the rig.
What is a semi-submersible?
Semi-submersible may refer to a self-propelled vessel, such as: Heavy-lift ship, which partially submerge to allow their cargo (another ship) to float into place for transport. Narco-submarine, some of which remained partially on the surface. Semi-submarine, which cannot fully submerge.
What is the biggest rig size?
Here’s a whistle-stop tour of six of the biggest oil rigs.
- Berkut. This 200,000 ton rig is situated off the Russian Pacific coast.
- Perdido. Operated by Shell in the Gulf of Mexico, Perdido (see image above) is the world’s deepest oil rig at 2.450 metres.
- Petronius.
- Hibernia.
- Olympus.
- Baldplate.
How do semi-submersible ships work?
A semi-submersible obtains most of its buoyancy from ballasted, watertight pontoons located below the ocean surface and wave action. Structural columns connect the pontoons and operating deck. With its hull structure submerged at a deep draft, the semi-submersible is less affected by wave loadings than a normal ship.
Why is it called a semisubmersible rig?
Definition: “Semisubmersible” or “Semisub-” is referring to Offshore drilling rigs so called because they are combining the advantages of submersible rigs with the ability to drill in Semisubmersible drilling rig. Instead, the rig is partially submerged, but still floats above the drill site.
How is a semisubmersible rig kept above the hole at a drill site?
A more popular design for semisubmersible rigs is the column-stabilized semisub. Here, two horizontal hulls are connected via cylindrical or rectangular columns to the drilling deck above the water. Mooring lines anchor the rig above the well, and dynamic positioning can help to keep the semisub on location, as well.
What is the largest boat ever built?
Seawise Giant
Size record. Seawise Giant was the longest ship ever constructed, at 458.45 m (1,504.1 ft), longer than the height of many of the world’s tallest buildings, including the 451.9 m (1,483 ft) Petronas Towers.
Do oil rigs float?
Simple physics. As with oil tankers, heavy load barges and cruise ships, deep sea oil rigs float according to basic physics. As the weight of the rig pushes downwards displaced water pushes upwards, thus keeping the structure afloat.
Who is the largest offshore drilling company?
Transocean Ltd
Transocean Ltd is the largest offshore drilling contractor in the world. In 2020, the Switzerland-based company reported 3.15 billion U.S. dollars in revenues.
What is the definition of a semisubmersible rig?
Definition of ‘semisubmersible rig’. semisubmersible rig in British. noun. (in the oil industry) a type of drilling platform that floats supported by underwater pontoons, with much of its structure below the water line for stability in high winds: usually used only for exploratory drilling for oil or gas.
What’s the world record for a semi submersible rig?
Semi-submersible rigs are used to drill wells in water depths up to 9,500 ft. The current world record water depth for a semi-submersible rig using dynamic positioning is 9,472 ft. Due to their stability, semi-submersible rigs are also preferred in harsh offshore environments.
Why are semi submersibles used for deep water drilling?
Semi-submersibles are the choice for drilling from a floating position, due to the deep water depths. Semi-submersible (“semi”) rigs float like a ship while being towed into position, where their pontoons can then be flooded, partially submerging the rig.
Which is the largest semi submersible platform in the world?
Notable platforms are as follows: 1 Petrobras 36 – Converted from drilling rig Spirit of Columbus and sank in 2001 2 Atlantis PQ – BP and BHP joint venture 3 Thunder Horse PDQ – GVA40000 design, largest semi-submersible platform More