With rising popularity, oil demand is increasing. That’s where companies find oil resources or fields, everywhere from land to ocean. Extraction of oil from land-based oil fields is easier. However, when extracting oil from the ocean, companies use FPSOs. But here is the question: what is floating production storage and offloading (FPSO)?
FPSO is a large ship that is structured like a large vessel. However, it includes all the equipment needed to refine crude oil, store it, and offload it. The use of FPSO makes the oil extraction from the sea or ocean easier. In this article, I will explain everything about FPSO. You’ll also learn about how these FPSOs work. So, let’s begin!
What is FPSO?
FPSO stands for “Floating Production Storage and Offloading”.It is a ship with extensive oil refining facilities. Remember, FPSOs differ from FSOs, as they have complete oil-refining facilities on board.
The oil resources of the field are not confined to the land. There are many subsea wells or fields where crude oil can be obtained. However, companies cannot build dedicated oil refineries at deep-sea locations. Right? That’s where FPSO facilities prove their worth.
These FPSOs (ships) can float on the water body and move from one location to another. Companies use them and send the crude oil to these ships. The FPSO has refining equipment onboard. These processes help separate contaminants and gas from crude oil, making it suitable for refining. After that, refined oil is stored in the storage compartment present on these FPSOs.
These storage tanks are large enough to store large amounts of refined oil. Once these tanks are filled, the shuttle tanker, a separate ship, approaches the FPSO. The oil is then offloaded from the FPSO to the nearby shuttle tanker. This oil is then transported to land. Without FPSOs, refining, storing, and offloading oil at sea would have been impossible.
Are commercial ships and FPSOs the same? Yes, but no. The FPSO has a hull and resembles ships used to carry passengers. However, they have additional storage and oil refining facilities on board. These extra facilities make FPSOs different from regular ships. But FPSOs are also ships, with advanced refining machinery.
Importance of FPSO
The use of FPSOs is a game-changer, especially for oil extraction in deeper water bodies. Without them, underwater oil fields would have been useless to humans. Here is how FPSO adds value:
- First of all, the employment of FPSOs is possible at any location in the sea. They can stay in deep water, where oil fields are deep beneath the surface. Without an FPSO, extraction from such a deep oil field would have been very challenging.
- As I said, FPSOs have onboard storage compartments or tanks. The tanks can store the refined oil for a longer duration. It means companies don’t have to use long underwater pipes to transport oil to land.
- FPSO has oil refining units or equipment onboard. That equipment separates the contaminants — gas and mixed water —from the oil. After that, the oil goes to the storage tanks. This reduces the need for additional land-based refineries.
- Remember, the FPSOs are ships that can float and move on the surface of water. If one oil field depletes completely, the companies relocate them to new oil resources or fields. This makes them excellent investments for oil extraction companies.
- Imagine building large oil-refining units in water bodies. That would have been very costly, especially in deep water. Right? FPSOs are cheaper to build, eliminating the need for onshore oil refineries. They are among the most effective ways of extracting and refining oil.
How Does FPSO Work? 4 Step Process
FPSO may seem complex, but the operation and working are relatively simple. In the section below, I will explain how FPSO works in four steps.
1- Oil Extraction from Subsea Wells
FPSO operations begin with crude oil extraction. But where does this oil come from? Remember, crude oil and gas are present beneath the surface of the sea, where rocks are present. These rocks keep the unrefined oil trapped. The companies drill the holes into the surface of the subsea using advanced machines.
These small holes are wells that help extract oil from the seafloor. Once wells are drilled, companies install risers (pipes) in the holes. These risers are connected directly to the FPSO on the water’s surface. Some risers are longer, and others are shorter, depending on water depth. These tubes or risers extract crude oil beneath the rocks and deliver it to the FPSO.
2- Refining & Separation of Crude Oil
As I said earlier, crude oil consists of different elements. Those include mixed water, gases, sands, and many other impurities. This oil is useless; it requires refining and additional processing. The FPSO has an onboard oil processing unit and dedicated separators.
These units separate the oil from mixed gases and water. Generally, the gases and mixed water are just released. However, the processed and refined oil is stored in tanks or compartments. In simple terms, an FPSO has a small oil refinery on board. This factor acts as a full-edge processing unit to remove impurities and refine the oil.
3- Oil Storage Compartment or Tanks
Remember, the FPSO has a hull similar to that of a regular ship. This hull in the FPSO has storage tanks or compartments. Storage capacity varies with the size of the FPSO. After processing and refining, the oil is sent to the FPSO’s storage tanks.
On average, FPSO storage tanks can store more than 2 million barrels of refined oil. However, if the FPSO is old, companies don’t burden it with such a high amount. They offload the oil from these tanks, ensuring less burden on the FPSO. Modern FPSOs offer greater storage capacity. This reduces the need for frequent offloading, allowing oil to remain stored.
4- Offloading to Shuttle Tanker
The last step in FPSO’s operation is the offloading of the refined oil stored in storage tanks. This is done only when the storage tanks are 90% full. During this, a separate ship, shutter tanker, is used. This shuttle tanker comes alongside the FPSO at the connection points.
Die STS-Schläuche are usful in connecting the storage tanks of the FPSO to the shuttle tanker. Once the connection is established, the FPSO pumps the oil. As a result, all the oil stored in the FPSO is transferred into the shuttle tanker via hoses. This oil transfer is not immediate and can take a few hours, depending on the quantity of oil being offloaded from the FPSO.
Once all the oil is offloaded, the hose is disconnected, and the shuttle tanks move away towards the land facilities. The FPSO’s storage tanks are ready to receive newly refined oil. This process continues to help companies extract and refine subsea well oils. Remember, this oil offloading happens under strict oversight to prevent leaks or other accidents.
Schlussfolgerung
Generally, people confuse FLNG and FPSO. Remember, both of these operate differently. FNLG is all about extracting natural gas. The FPSO only extracts and refines the crude oil. Interestingly, the FPSO even wastes the gases that come mixed with crude oil.
It is noteworthy that these marine vessels enable subsea oil extraction. Without them, companies may never be able to utilize the oil fields present in the ocean. Why? The reason is that building oil refineries on the sea surface is very costly and challenging. In this article, I’ve discussed everything about FPSOs and their basic working.