The marine industry is highly diverse and has the potential to provide us with oil, gas, and other valuable resources. Right? There are different oil and gas fields in the sea (subsea wells). The companies use both FSO and FPSO in the process of extracting oil and gas. However, many people hold unique opinions about these ships, leading to a debate over FSO vs FPSO.
Both FSO and FPSO are ships that have storage compartments or tanks. The FSO stands for the Floating Storage and Offloading unit. It is a ship equipped with a storage system that retrieves oil from an oil field and stores it for a period, and then offloads it. On the other hand, FPSOs are more advanced ships, as they are capable of refining oil while also offering storage facilities. In this article, I’ll discuss all the key differences between FSO and FPSO.
Overview of FPSO vs FSO
First, FPSO and FSO are both types of marine ships or vessels. However, they differ from each other in terms of their job, specifically the storage and refining of oil. Neither of these ships is involved in cargo or passenger transportation. Instead, their sole functionality is to store and then offload the oil.
FSO and FPSO are ships with hulls and storage systems. The crude oil from the oil field is transferred into their storage compartment using the hoses and pipelines. The FSO offers no additional functionality, storing only the oil and then offloading it. On the other hand, FPSOs provide dual functionality. They help store crude oil and then refine it as well.
As I said earlier, FSO is capable of storing and then offloading the crude oil. This ship has mooring lines and anchors to secure its position near the oil field. The crude oil or gas is transferred from the oil well (field) to this ship through hoses. This transfer of oil is generally done using STS or floating hoses. This oil is stored in the storage compartment of the FSO.
When the storage tank is full, another ship approaches the FSO. The stored oil is then transferred to the new (shuttle tanker). After that, the crude oil is transferred to the offshore refineries for processing. However, the FPSO ship comes with added features or functionality. It can store the crude oil and refine it.
In simple terms, an FPSO acts as a small refinery, while also serving as a storage compartment. Are you wondering about how FPSOs can refine crude oil or gas? This vessel features complete oil processing equipment on its deck. This equipment is employed when oil is stored in the storage tanks. It separates oil and gases from the provided crude oil.
What are the Differences Between FSO and FPSO?
As I mentioned earlier, FSO stands for “Floating Storage and Offloading units.” On the other hand, FPSO represents “Floating Production, Storage, and Offloading units.” However, their differences go beyond the abbreviation of these terms. Both of these vessels serve a storage function, but FPSO offers additional functionality.
In the section below, I will discuss all of the key differences between FSO and FPSO.
1- Functionality
The significant difference between FSO and FPSO lies in their functionality. An FSO vessel or ship’s job is to store the crude oil or gas. This ship has a large storage tank or compartments. The ship is moored near the oil field. After that, the oil is transferred from the oil field to the vessel with marine hoses. These ships have no other functionality except to store crude oil and then offload it.
However, the FPSO vessels are more advanced and feature facilities for refining crude oil. These basic structures, FPSO and FSO, are the same. However, the FPSO ship is equipped with processing equipment. This equipment enables the vessel to refine raw oil and separate gas and oil from it. In short, FPSO offers two benefits: storing the oil and then refining it.
2- Processing Capability & Equipment
As I said earlier, FPSO acts as a small oil factory. But the question is, how does it refine the oil and then store it? These FPSO vessels are equipped with oil processing equipment or tools. The list of some of the vital oil refining equipment is as follows:
- Gas compressors
- Large-sized heaters
- 3-phase separators
- Electrostatic treaters
- Water treatment units.
First, the raw (crude) oil is transferred from the oil field or well to the FPSO. After that, oil processing equipment is employed on the crude oil. The 3-phase separator plays a crucial role, as it separates the crude oil into three distinct layers. The first layer is generally composed of gases, the middle one is oil, and the last layer is a mixture of water and chemicals.
All the processing equipment is used to separate and refine crude oil into oil. This equipment generally remains on the ship for refining the incoming oils. However, the FSO doesn’t have this processing or refining equipment. As a result, this ship can only store crude oil and is unable to refine it.
3- Source of Oil
FSO and FPSO also differ in terms of the source of their oil. As I said earlier, FPSO has oil processing equipment and facilities. Right? This ship is generally connected to the subsea wells. It receives raw fluid containing crude oil, gas, and mixed water from these wells. These fluids undergo separation, filtration, and refining at the FPSO.
On the other hand, FSO doesn’t have processing facilities. Therefore, they are generally not directly connected to the subsea well. Instead, FSO vessels get partially processed crude oil from nearby oil refining facilities. The raw oil is partially processed on these platforms (facilities). After that, this partially crude oil is transferred to the FSO using hoses.
Quick Highlight: There are multiple refinery units near the subsea wells. The FSO gets oil from these nearby facilities. These facilities partially process the crude oil. As a result, the oil becomes more stabilized and safe to be stored on the FSO. After their partial processing, it is loaded in the storage section of FSO using the hoses.
4- Complexity & Lifespan
Interestingly, FPSOs are significantly more complex than FSOs. Why? The reason is that this vessel has more responsibilities. For example, it handles the loading, storing, processing, and refining of oil. There are multiple pieces of processing equipment present on top of the storage compartment or tank. The FPSO handles the processing of oil on a regular basis and remains active at all times.
Due to this, wear and tear of FPSOs is more common. Therefore, the lifespan of an FPSO is typically around 15 years. On the other hand, FSOs are simple ships having two basic roles. First, they store the crude oil, and then offload it when the shuttle tankers arrive. Additionally, the FSO is exposed to fewer frequent operations. As a result, its lifespan is improved, and it can serve for up to 25 to 30 years in the field.
5- Deployment Area & Mobility
FPSO and FSO differ from each other in terms of their deployment areas. One thing is for sure: both are deployed in the sea. However, FPSOs generally remain in ultra-deepwater oil fields. Remember, this vessel operates in areas where the water level is extremely deep. On the other hand, the FSO remains typically in shallow water.
The FPSO is typically used in remote areas and remains moored there for extended periods. However, this vessel can move in case of bad weather. Similarly, the FSO vessel can move, but it remains stationary at one point. As it stays in the shallow water, bad weather does not affect it badly. As a result, it remains moored and stays connected with the oil facility through the pipelines.
6- Crew Size & Gas Handling
The crew size is generally larger on the FPSOs. This makes sense because FPSO is involved in multiple operations. First, it stores the crude oil coming from the subsea wells. After that, the crude oil undergoes separation, filtration, and refining.
These additional functionalities require more crew and labor to ensure the smooth working of FPSO. On the other hand, FSOs don’t have large crew sizes. The reason is that FSO handles only the storage and offloading of crude oil. There is no oil refining on the ship. So, a small crew size is enough to handle the storing and offloading of vessels.
As I mentioned earlier, FSO typically receives partially processed oil with gas flared off. There is not much gas handling on the FSO. However, FPSOs have additional duties related to the transportation and processing of crude oil. Therefore, they must utilize various equipment, including compressors and other tools, to handle the gas. The gas handling on FPSO makes it more complex to work with.
7- Dependence On Other Units
FPSOs are generally independent of other units or oil refinery facilities. Why? The reason is that these vessels have storage tanks and onboard oil processing units. They get the crude oil from the subsea wells. After that, they can store and refine the oil.
The gas mixed with crude oil is flared off using advanced tools and equipment. The pure oil is then stored and later offloaded. All these operations are performed independently on the FPSO. However, the FSO is dependent on the nearby oil refineries or facilities. As said earlier, FSO does not have oil processing equipment on it. The crude is partially processed at the refinery unit located near the subsea well.
This partial processing flares off the gases mixed in the crude oil. After that, the oil becomes more stabilized and is stored in the FSO’s storage tank. Without this other oil refiner, the FSO cannot operate and depends on the secondary oil refineries. Remember, FSOs are typically deployed near refineries, where they are located close to the oil source.
8- Cost & Safety
The FPSO is generally more expensive than the FSO. The reason is that these ships come with advanced features and facilities. In fact, many people consider them small refineries due to the processing equipment they have onboard. They can store the oil, refine it, and flare off gases. These advanced setups on a single ship make it very costly.
Additionally, FPSOs require a large crew size to handle different activities. All these factors increase the operational cost of the FPSO. On the other hand, FSOs are generally less expensive, as they don’t require advanced setup or processing equipment. When it comes to safety, the FSO stands out as a superior option. Remember, FSO gets partially processed crude oil.
The gas generally flares out from this crude oil. Crude oil with gas makes FSO safer. It is noteworthy that the FPSO also features advanced systems for gas handling and the ship’s safety. However, it still has to face the mixed gas, separate it, and flare it out. These additional steps in handling gas make FPSO less user-friendly.
Conclusion
Both FPSOs and FSOs are crucial for marine operations. They help extract the oil from the subsea wells and oil fields. Due to their fancy names, people don’t understand these excellent maritime assistance. Both FSO and FPSO are types of ships or vessels that float on the water surface. However, they are not used for cargo or passenger transportation.
Instead, they have large storage compartments for oil storage. They are used on oil reservoirs and collect oil from oil fields. After that, they transfer oil to the shuttle tanker. The FPSO is an advanced ship as it can store, offload, and refine crude oil. On the other hand, FSO is a simple ship or vessel that only stores the partially processed crude oil and then offloads it.