FPSO Vessel: Transforming Offshore Production
What is an FPSO?
An FPSO vessel or (Floating Production Storage and Offloading) is a floating production systems used in the offshore oil and gas industry.
Conversely to traditional production platforms, they act as a mobile form of production facility, capable of extracting and storing oil and gas. This means that they can quickly station at subsea reservoirs, empty them, and move on to a new location.
FPSO Vs FSO
You may also have heard of an FSO (Floating Storage and Offloading) vessel. These are different to FPSOs, intended not to produce oil and gas, but to store it and transport it.
FPSOs often offload to FSOs, which then offload to an even smaller storage vessel, or directly to port.
The difference between them is simple, yet commonly misunderstood.
FPSO Vessel Basic Operation
The basic function of floating production storage and offloading vessels proceeds roughly as follows:
FPSO Deployment
FPSOs often start life as very large crude carriers (VLCC) or a gas tanker. These then receive a system design overhaul, fitted with floating production systems for extraction and processing of crude oil and gas. FPSO projects usually take a year or more.
Next, the FPSO is deployed into active service, expected to carry out around 10 years minimum at sea. It sails towards installation at its first oil field.
FPSO Installation
The floating production storage and offloading vessel arrives at the oil field, where installation begins.
FPSOs tend to have more advanced mooring systems today in order to operate in rougher conditions during offshore production. These are deployed to safely anchor the floating vessel to the sea bed via mooring lines.
The mooring turret is then connected to subsea risers which act as flowlines for oil or gas from subsea wells.
Extraction
Following installation at the subsea risers, the extraction process begins as the pumping system initiates. Crude oil or gas begins to flow through the flowlines into the ship’s storage units.
Processing
Once the flow of crude oil or gas begins, the product is then taken through several stages of processing.
In the case of crude oil, the primary process is the removal of any undesirable particulate and separation of the liquid oil from its gaseous elements. This takes place through a mix of high and low pressure separators, high temperature heat exchangers and electrostatic treaters.
The process of gas processing is far more complicated. Compression, refrigeration and cooling systems are used to liquefy the gas. Continuing through the onboard processing systems, the gas must be scrubbed to remove any condensates, passed through absorption towers and filters for dehumidification before finally being cooled by a decompressor.
Storage
Now that the production phase is over, the product can be stored in the tanker until a shuttle tanker arrives to collect it. Many Floating Production Storage and Offloading vessels are capable of storing millions of barrels of oil and gas before offloading is required.
Offloading System
Shuttle tankers or will regularly moor with FPSOs to transport their product back to shore or an offshore pipeline. A ship to ship transfer takes place between the shuttle tanker and the FPSO via the offloading system. Once transfer is complete, the FPSO continues its production project and the tanker departs.
Relocation
Once a field has been emptied of hydrocarbons, it’s time for the FPSO to move on and service a new field. The Floating Production Storage and Offloading vessel starts a new project and will remain in service until those wells also run dry.
Benefits Of FPSOs
FPSOs have a host of advantages over other floating production systems. Here are some of the reasons why FPSOs are the superior method of extracting oil and gas today.
Mobile Production
FPSOs are mobile; either they are self-powered or are towed by a barge. Therefore they can quite quickly move between oil fields to a new location once the well at which they are stationed has run dry.
Quick Deployment
The average oil and gas rig project can take 3-4 years to build and deploy. Meanwhile, an FPSO can be constructed or converted from an oil tanker in around 1 year, meaning it can begin operation sooner.
Accessing Difficult-To-Reach Wells
FPSOs are capable of reaching subsea wells in extreme deep water locations as well as remote locations far from shore. This makes them a vital asset as reservoirs in shallower waters are depleted over time.
Due to their reinforced design, they are capable of withstanding harsh environmental conditions at sea. They are also able to work in remote locations, far from shore and any established pipelines, thanks to their huge storage capacity. The result is that these floating storage units can store oil and gas in large quantities before they have to return to shore.
Cost Effective
Due to their ability to reach remote locations and reposition quickly, FPSO vessels are an extremely cost effective method of extracting oil and natural gas. Installation of a traditional oil or gas production rig can cost anywhere between $100 million and $1 billion.
While FPSO vessels can cost upwards of $750 million, they can have life-cycles between roughly 10 and 20 years. This means that the return on investment for a Floating Production Storage and Offloading vessel is far higher than other floating production systems.
Self-Sustaining
FPSOs with gas production capacities can also treat some of the gas for on-board power generation. Natural gas is an extremely clean and effective fuel and results in a highly efficient self-sustaining system on board the FPSO.
FPSO Variants
FPSOs come with a range of specifications, meaning they can be equipped with different technology according to the requirements of their proprietor.
FDPSO (Floating Drilling Production Storage And Offloading)
Not all FPSOs come equipped with drilling capability. However, those that are able to be converted to carry specialist subsea equipment are capable of drilling new subsea wells and floating production.
The result is an even more mobile and independent FPSO system which can operate anywhere around the world. Although, the primary downside is that only larger FPSOs can be converted to carry the specialist drilling equipment required to establish new oil and gas fields.
FLNG (Floating Liquid Natural Gas)
Floating production storage and offloading vessels which specifically extract and process natural gas are often referred to as FLNGs. These vessels are capable of treating the extracted gas onboard into liquid hydrocarbons for easier storage and transportation.
They also feature onboard cooling as part of their storage system. This maintains the hydrocarbons in their liquid state throughout their transportation.
The Future Of FPSOs
In recent years there has been an acceleration in the number of FPSO project developments. Currently there are an expected 140 Floating Production Storage and Offloading vessels in the production pipeline. These include vessels with a variety of oil and gas processing systems.
This increase in development of FPSO vessels is due to the heightened demand for natural gas in particular. In fact, the demand on the natural gas industry is expected to grow consistently by around 3.5% year-on-year until at least 2035.
Required crude oil production is set to increase by 6% until 2025, however its future from there is uncertain. This is due to moves towards less polluting fuel from hydrocarbons such as natural gas, biofuel, or alternatively a range of renewable energy sources.
Conclusion
Floating Production Storage and Offloading (FPSO) vessels are an incredible development in the hydrocarbons industry. They can be designed with various technology, catering to the demands of markets and offshore conditions alike.
As the world experiences rising pollution from carbon emissions, the international community strives to find solutions. Cleaner and more efficient than other hydrocarbons, LNG could rise in popularity. Correspondingly, the liquefied gas industry is likely to benefit from a significant boom in business over the next decade, and perhaps beyond.
FPSOs will provide an invaluable asset in meeting rising hydrocarbon demands in the future, streamlining the gas and oil production process. For more information on the offshore industries, visit our website.
