The FPSO Full Form is Floating, Production, Storage and Off loading vessel. The Floating production system is a floating oil platform which may be equipped with gas compression and water injection system, in addition to oil processing equipment.
After processing, the stabilized crude oil is stored in the in the ships cargo tanks prior to being transferred in to shuttle tankers via mooring hawser and hose, reeled from the stern of the vessel.
Gas produced as by-product of oil production is normally used as fuel for the gas turbine powered electricity generators or where significant volumes are produced and an export pipeline is not available, it may be re-injected in the formation or flared when production exceeds demand.
FPSO Vessel is designed to receive hydrocarbons produced from nearby platforms or subsea template, process them, and store oil until it can be offloaded onto a tanker or, less frequently, transported through a pipeline
There are some significant design challenges which have had to be overcome to make the FPSO a viable proposition for long term field development goals. Whilst these relate primarily to the mooring system, turret and the flexible risers, the basic hull and the topside processing equipment all must be designed to a higher specification than those of a conventional tanker or offshore structure.
Main Parts of the FPSO
A number of existing tankers have been converted for service as FPSO’s and in some cases they have retained their original propulsion system. Where operators have opted for new purpose built vessel, main propulsion systems are generally omitted, the vessel relying on the electrical powered thrusters units to assist in station keeping.
The hulls are built in accordance with rules provided by the ship classification societies and are designed to remain on station for a period of 10-20 years without dry-docking.
The topside oil and gas processing equipment is designed and constructed in accordance with fixed offshore platform and refinery standard, specification as per American Petroleum Institutes, American society of Mechanical Engineers (ASME).
How ever the code and standards must be adapted to take account of vessel motion. The additional loading due to wave action can be considerable and have a serious effect on the fatigue life of the equipment, particularly the process vessels and pipe works.
The Process equipment is normally per-assembled into skids, the skids being mounted on a framework on pillars 3 meter above the main deck of the vessel, the air gap providing some protection against green seas, large waves breaking on the deck and to provide adequate hazardous area boundaries.
The turret consists of a large diameter around 16-32m vertical cylinder which sits within the hull of the vessel, mounted on heavy duty roller bearings. The mooring wires and the flexible sub-sea risers are attached to the turret which prevents it from rotating. The vessel is thus free to rotate through and angle of 270 deg around the fixed turret under the influence of wind, waves and currents, the extent of rotation being controlled by the vessel’s azimuth thrusters unites.
A spread of 8 to 14 anchors ensures that the FPSO remain on location whilst producing oil, the anchor spread typically consisting of a combination of wires and chains which are tensioned by winches within the turret. Convectional anchors, suction anchors or piles may be used to make the connection with the sea bed.
A mooring system is made up of a mooring line, anchor and connectors, and is used for station keeping of a ship or floating platform in all water depths. A mooring line connects an anchor on the seafloor to a floating structure. We will focus on mooring Mobile Offshore Drilling Units and Floating Production Systems.
The mooring line can be made up of synthetic fiber rope, wire and chain or a combination of the three. Environmental factors – wind, waves and currents – determine which materials make up the mooring system.
To permit the FPSO to move both vertically and laterally the connections to the sub-sea wells are made through flexible, steel reinforced risers. The risers are designed to absorb any wave induced motion which might affect the position of the vessel, often being draped over submerged mid-line buoys which help in reducing the loads on both the risers and the turret the oil being transferred from the turret to the process equipment through a swivel stack.
It is the swivels and to a lesser extent the risers which are currently the limiting factors in the development of ultra deep-water FPSOs, gas export lines in particular being difficult to install successfully and limited to a diameter of less than 16 inched at operating pressure of 340 bar.
Another problem which increases with water depth is the risk of hydro-static collapse of the risers, a typical maximum water depth for a steel-reinforced riser of 8-10 inch diameter being approximately 800-1000 m.
Storage and offloading systems
The storage and offloading systems in an FPSO (Floating Production Storage and Offloading) are responsible for storing the produced oil and gas, and offloading them to tankers or other vessels. The system typically consists of the following components:
- Storage tanks: The storage tanks are the main component of the system. They are typically cylindrical in shape and made of steel. The tanks are designed to store the produced oil and gas under pressure.
- Offloading pumps: The offloading pumps are used to transfer the oil and gas from the storage tanks to tankers or other vessels. The pumps are typically driven by electric motors or gas turbines.
- Loading arms: The loading arms are used to connect the FPSO to the tankers or other vessels. The arms are typically made of steel and are designed to withstand the forces of loading and offloading.
- Valves: The valves are used to control the flow of oil and gas through the system. The valves are typically made of steel and are designed to withstand the pressures and temperatures of the oil and gas.
The storage and offloading systems in an FPSO are critical to the operation of the unit. They allow the FPSO to store the produced oil and gas until it can be offloaded to tankers or other vessels. The system also helps to ensure that the oil and gas are transferred safely and efficiently.
How does an fpso work
An FPSO, or floating production storage and offloading unit, is a floating vessel that is used to produce, store, and offload oil and gas. FPSOs are typically anchored to the seabed and are used in deep water where it is not economical to build a fixed platform.
FPSO has three main components
- The hull is the floating structure that supports the entire unit. The hull is typically made of steel or concrete and is designed to withstand the forces of the sea.
- The topsides are the processing facilities that are located on top of the hull. The topsides include equipment for separating oil and gas from water, as well as equipment for treating the oil and gas.
- The storage tanks are located below the hull and are used to store the produced oil and gas. The storage tanks are typically made of steel and are designed to withstand the pressure of the oil and gas.
The basic operation of an FPSO is as follows
- Oil and gas are produced from subsea wells and are transported to the FPSO through flowlines and risers.
- The oil and gas are separated from water and other impurities in the topsides processing facilities.
- The treated oil and gas are stored in the storage tanks.
- The oil and gas are periodically offloaded from the storage tanks to shuttle tankers or to onshore pipelines.
FPSO oil and gas are a cost-effective way to produce oil and gas in deep water. They are also a flexible solution, as they can be moved to different locations as needed.
Advantages of using FPSO in oil and gas
- They are a cost-effective way to produce oil and gas in deep water.
- They are a flexible solution, as they can be moved to different locations as needed.
- They are less environmentally disruptive than fixedplatforms.
Disadvantages of using FPSO in oil and gas
- They can be more expensive to install than fixed platforms.
- They are more complex to operate than fixed platforms.
- They are more vulnerable to weather damage than fixed platforms.
what is fpso projects
FPSO projects are the development and construction of floating production, storage, and offloading (FPSO) units. FPSOs are floating vessels that are used to produce, store, and offload oil and gas. They are typically anchored to the seabed in deep water where it is not economical to build a fixed platform.
FPSO projects typically involve the following stages
Conceptual design: This stage involves the development of a preliminary design for the FPSO unit. This includes the selection of the hull, topsides, and storage tanks, as well as the design of the production and offloading systems.
Front-end engineering and design (FEED): This stage involves the detailed engineering of the FPSO unit. This includes the preparation of detailed drawings and specifications, as well as the development of a cost estimate for the project.
Construction: This stage involves the construction of the FPSO unit. This is typically done at a shipyard, and can take several years to complete.
Installation: This stageinvolves the installation of the FPSO unit at the oil and gas field. This includes the anchoring of the unit to the seabed, as well as the connection of the unit to the subsea production system.
Operation: This stage involves the operation of the FPSO unit. This includes the production of oil and gas, aswell as the offloading of the oil and gas to shuttle tankers or onshore pipelines.
FPSO projects can be very complex and challenging. They require a significant investment of time and money, and there is always the risk of delays or cost overruns. However, FPSOs can be a valuable asset for oil and gas companies, as they provide a cost-effective and flexible way to produce oil and gas in deep water.
key considerations for FPSO projects
The location of the oil and gas field: The location of the oil and gas field will determine the size and type of FPSO unit that is required.
The depth of water: The depth of water will also determine the size and type of FPSO unit that is required.
The production capacity: The production capacity of the FPSO unit will depend on the size of the oil and gas field.
The cost of the project: The cost of the FPSO project will depend on the size and complexity of the unit, as well as the location of the oil and gas field.
The environmental impact: The environmental impact of the FPSO project must be considered, and mitigation measures must be put in place.
Overall, FPSO projects are a complex and challenging undertaking, but they can be a valuable asset for oil and gas companies.