There are two main types of offshore oil rigs: drilling and production. Those in the first group serve to find oil in wells that have not yet been explored, a task that is not easy, which begins with a series of geological and geophysical surveys that locate promising basins and analyze the best points to drill them. Even so, no one can guarantee the real existence of oil. In the end, less than 20% of wells drilled are used.
Production platforms, in turn, come into play when a well has already been discovered and is ready to be explored. They are the ones that effectively extract the oil located at the bottom of the sea, taking it to the surface, where the oil is separated from other compounds, such as water and gas. Depending on the depth at which the well is located, two types of production platforms can be built: fixed and floating (called semi-submersible). The fixed ones are installed in shallow waters (up to 180 meters) and are connected to the ocean floor by a kind of large “pillar”. The floating ones, on the other hand, have hulls like those of a ship and serve to explore wells that are located in very deep places. In the Campos basin, for example, in Rio de Janeiro, oil is extracted in waters that reach almost 2,000 meters in depth.
Today, Brazil has a total of 93 offshore production platforms, both fixed and floating. Together, they are responsible for approximately 85% of all oil extracted here. Thanks to such platforms, by the end of this decade the country should be self-sufficient in the production of the product.
Floating platforms look like ships and extract oil at a depth of almost 2,000 meters
1. GIANT BUOYS
The floating platform is supported by two large hulls, which are around 50 meters high. Approximately half of the hull is underwater, below wave action, which ensures greater stability. Inside, elevators give access to fuel tanks, water reservoirs and sewage box.
2. SUBMARINE CENTER
On the ocean floor, at the mouth of the oil well, there is a set of valves called the “Christmas tree”. It centers the pipelines that penetrate underground at various points in the extraction field. From the “Christmas tree” the mixture of gases, oil and water coming out of the well goes to the platform, in a connection that can be more than 2 kilometers long
3. ROBOT DIVER
In the old days, divers inspected the pipes and hulls. Today, most inspection and maintenance work is done by small robots that send images to technicians. The interior cleaning of the pipes is also done with remote monitoring
4. RELEASE ANCHORS!
Despite not having a pillar connecting it to the ocean floor, the floating platform does not remain loose in the sea. Special anchors, driven 30 meters underground, are used to keep it in place. The anchor lines are made of polyester, a flexible material that helps lighten the weight on the platform. Steel chains are only used at the beginning and end of the cables
5. TEMPORARY HOUSING
In the safest area of the platform – close to the helipad – is the housing sector. In addition to accommodation, it has a restaurant, TV or cinema room, games room and sometimes even space for a sports court. There are always around 150 employees working on the platform. They spend 14 days at sea and then get 21 days off on land.
6. INDUSTRIAL SEPARATION
The production platform resembles a refinery. As soon as the mixture of water, gas and oil that comes from the ocean well reaches it, a series of equipment separates these substances. Water is returned to the sea and oil and natural gas are sent to shore. Unusable gases burn in that eternal flame that you see on the platforms
7. GASEOUS PATH
The natural gas separated on the platform is taken to the coast through pipelines fixed to the bottom of the sea and which can cover distances of up to 120 kilometers. Oil can also be transported by similar pipes, but often, due to costs, the option is to use boats to transport the extracted oil.
8. AQUATIC WAREHOUSE
When the oil does not go to the coast through an oil pipeline, it is stored in a ship that works as a large aquatic warehouse. With the use of chains, it is fixed at about 2 kilometers from the platform and receives the oil extracted from it (through a pipe). Once a week, a smaller vessel relieves the stock and takes the product to shore.