The derrick is made of a collagen-resistant alloy material, which can resist high pressure and temperatures, as well as the hydrogen sulphide found at those depths. Once it's known how many wells can be drilled, Adnoc needs to connect them with pipelines. These are used to deliver the oil and gas to central processing facilities.
Electrical submersible pumps are sometimes used to bring oil to the surface. The graph below shows how the price of oil matches with the production.
Image Credit: Wendover Productions screenshot. So, given the cost, why would a company build an offshore oil rig that costs up to 20 times more than an onshore drilling rig? Well, as good places to drill on land dry up or are already being tapped, people turn to the ocean.
There is a lot of oil beneath the ocean floor, so the higher startup cost offsets the long term return. Bigger rig, bigger investment, and more oil in your barrel. Where are these rigs set up? Usually drilling locations are chosen near where other rigs are already drilling such as the Persian Gulf, Gulf of Mexico, or the North Sea. How do they pick the exact spot? Geological surveys and satellite images are used to find the best specific location. Once a rig is on location, it doesn't have to stay there.
If the oil in a well runs dry or the rig needs maintenance, offshore oil rigs can actually travel to different locations. Common reasons for the rigs to be moved are to go to a new location or simply to be brought back to shore for maintenance. For the most part though, they stay in one place for years at a time. In the video below, Scarabeo 9 , a large, semi-submersible rig built by Saipem is crossing the Bosporus Strait.
A shipyard where it will get maintenance for future jobs. In the video you can see it passing under 3 bridges, just barely clearing the last one! Some offshore rigs are anchored to the bottom of the ocean while others use dynamic positioning to stay in place.
A Floating Production Systems FPS is a semisubmersible drilling rig containing petroleum production equipment, as well as drilling equipment. Ships can also be used as floating production systems. The platforms can be kept in place through large, heavy anchors, or through the dynamic positioning system used by drill ships.
With a floating production system, the wellhead is actually attached to the seafloor once the drilling is completed, rather than being attached up to the platform. The extracted petroleum is transported via risers from this wellhead to the production facilities on the semisubmersible platform. These production systems can operate in water depths of up to 6, feet meters.
A Tension Leg Platform TLP consists of a floating structure held in place by vertical, tensioned tendons connected to the sea floor by pile-secured templates. Tensioned tendons provide for the use of a TLP in a broad water depth range with limited vertical motion. Picture a colossal mass of steel and iron floating in the open ocean. From all sides the structure is dripping with cranes, platforms and workers that all appear to be perfectly stable and at ease.
Oil rigs are a true feat of innovation and never fail to make an impression. But how exactly so they float?
Read on as we uncover what keeps these mammoth edifices above water level. 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. The official term for a buoyant oil rigs is a floating production system. The main types are classified as FPSO systems, which stands for floating production, storage and offloading.
Floating production systems are generally utilised in water depths ranging from to 6, feet. The structures feature large mono-hulls and are generally manufactured in the shape of a ship. All are equipped with processing facilities and are designed to stay in one place for an extended period of time.
While some rigs are functional, others are used exclusively to store extracted oil and gas. These variants are simply called FSOs which stands for floating storage and offloading systems or FSUs floating storage units. Oil rigs are designed by hugely talented engineers that equip them with a myriad of innovative features.
Some deep water platforms are semi-submersible thanks to internal ballast and buoyancy chambers.
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