Today, the need for development of offshore oil and gas resources in increasingly deeper waters is becoming more important because of many reasons associated with the world economy and the related energy resource development constraints and strategies.

Fixed-type offshore platforms, which have been useful for oil and gas developments in relatively shallow waters, are now much less feasible as we move further in developing oil and gas fields in deep- and ultradeep-water areas, now reaching more than 1,000m water depth. Floating-type offshore structures have to be increasingly considered to develop these deep-water areas. In addition to ship-shaped offshore units, at least three other types of floating production systems – semisubmersibles, spars, and tension leg platforms (TLP) – are also available today for that purpose. All of these types of floating systems require storage, pipeline infrastructure, and other associated field structures and systems to transport produced oil and gas to the facilities on shore, but perhaps to varying degrees.

That the use of ship-shaped offshore units remains a very attractive alternative in many cases of field development is attributable to its ability to successfully serve multiple functions, such as production, storage, and offloading, and the capability for oil or gas to be transported to shore via shuttle tankers. Ship-shaped offshore units reduce need for pipeline infrastructure and are functional on a fast-track basis.