FPSO — floating production, storage, and offloading systems; offloading of the crude oil to a shuttle tanker;

These are typically converted or newly built tankers that produce and store hydrocarbons, which are subsequently transported by other vessels to terminals or Deepwater ports.

FPS — floating production systems

Universal term to refer to all production facilities that float rather than are structurally supported by the seafloor;

Included would be TLP’s, spars, semi submersibles, shipshape vessels, etc.

The term is also frequently used to describe the general category of floating production facilities that do not have onsite storage.

The term is also used by the American Bureau of Shipping to describe a classification of floating production facilities that do not have storage capability

FSO — floating storage and offloading system;

Like the FPSO, these are typically converted or newly built tankers.

They differ from the FPSO by not incorporating the processing equipment for production;

The liquids are stored for shipment to another location for processing.

Offloading — transfer of produced hydrocarbons from an offshore facility into shuttle tankers or barges for transport to terminals or Deepwater ports.

An FPSO relies on subsea technology for the production of hydrocarbons and would typically involve pipeline export of produced gas with shuttle tanker (offloading) transport of produced liquids.

FPSO’s are relatively insensitive to water depth compared with other types of FPS’s.

To date, nearly all FPSO’s have been installed in water depths less than 3,000 ft.

Figure shows the typical field deployment of an FPSO.

An additional schematic, Figure, shows a simplified breakdown and relative position of the major FPSO unit components

The hull of an FPSO is typically ship-shaped Non-ship shaped also exists

Can be a monohull structure such as a spar or purpose-built barge-shaped vessel.

The typical existing FPSO can be characterized simply as a tanker with dimensions ranging as follows:

length — 600 to 1,100 ft. breadth — 100 to 200 ft. depth — 60 to 100 ft.

Of those systems deployed to date, most have been conversions of smaller and older tankers.

One of the major advantages of conversions is the rapid time to first production.

New, purpose built FPSO’s have become more prevalent in recent years as operators incorporate specialized needs, move into challenging (weather) environments

The main topsides processing system components might involve

crude oil, gas, and water separation;

water injection equipment;

gas compression;

chemical injection;

control systems for the subsea production equipment;

and associated piping.

The processing system varies little from other development concepts (fixed platform, TLP, or other floating facility serving as a host for subsea).

One area that does differ is the need to account for motion of the facility, which requires specialized designs for the production separators

Another difference from current typical systems is that operators may choose to move liquids such as wet oil, dry oil, and production system additives to in-hull tanks.

Since the fluids can be placed below the deck, they will not have as significant an effect on stability as if placed higher.

Thus, operators may also choose to hold larger volumes than for current typical systems.

Gas handling may be different for FPSO’s than for typical current systems.

All current production systems in the Gulf Of Mexico(GOM) use gas-export lines.

While this may still be a viable option for FPSO’s in the GOM, it is anticipated that operators will investigate the possible use of gas conversion technologies.

The Minerals Management Service(MMS) is on record as not allowing long-term gas flaring or reinjection into the formation.

Two options exist for FPSO station keeping

Majority of existing FPSO’s employ a fixed mooring system using anchors and anchor lines;

A few rely on dynamically positioned systems that employ a series of thrusters and positioning technology (satellite, GPS, etc.).

The fixed mooring system can be further described as permanent or disconnectable.

Most FPSO’s deployed to date (and planned) are permanently moored

They are designed to remain at the location throughout all anticipated environmental (weather) situations;

There are few that have been designed to be disconnected under severe weather circumstances such as typhoons and hurricanes, or threat of icebergs.

Choice of mooring depends on

Water depth,

company preference,

distance from shore (that is, the ability to get personnel off the vessel in a timely manner),

economics (as such relates to design capabilities),

and the relative risks.

Disconnectable mooring systems offer an operator the ability to transport both personnel and assets out of harm’s way during harsh environmental conditions, such as hurricanes, typhoons, and icebergs (Figure).

The design basis for power supply focuses on three categories:

Main power supply (all electrical functions during normal operations),

Essential power supply (startup of essential services, shutdown of facilities as needed),

Emergency power supply (life support during a “survival at sea” situation).

In addition to the conventional power generation needed for production processing, an FPSO may need power for the thrusters used in support of or in lieu of the mooring system.

The living quarters for an FPSO would typically accommodate 50 to 100 persons and could involve either the integrated superstructure of a converted ship’s quarters or the addition of a typical offshore quarters building.

The staff on board would closely resemble that of a currently operating TLP or other FPS (less drilling crew), which includes a marine crew that handles ballast control and product transfers, and the production crew that handles the processing of the produced hydrocarbons.

The FPSO’s installed to date have storage capacities ranging up to 2.3 million barrels

The storage volume provided in an FPSO is a factor of available ship size (if a conversion), availability and size of offtake vessels (likely the main reason), projected downtime (weather and operational), and cargo destination (port size, shipping limitations, etc.).

By definition, produced liquid hydrocarbons from an FPSO are offloaded into a shuttle tanker that transports the product to existing infrastructure (or to shore).

The offtake system includes the equipment associated with moving the liquids from FPSO storage tanks to the shuttle tanker, plus the moorings, buoys, transfer hoses, and other equipment used during the transfer operation.

This operation and equipment would be similar for facilities that do not employ storage, but use direct shuttle loading (DSL), where liquids are produced through the offtake systems directly into the shuttle tanker.

The offtake systems used for FPSO’s, FPS’s, or other offshore installations include tandem (Figure ), side-by-side (Figure), single-point, and remote systems