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development of offshore fields in deep waters worldwide. These
include FPSOs or FSOs operating in harsh environmental areas
and also waters of more than 1,000m depth; see FSO/FPSO
performance records by Single Buoy Moorings, Inc. for examples.
It is hard to say with precision exactly when ship-shaped
units made their appearance on the offshore oil scene. Certainly,
oil storage and shuttle tanker-mooring facilities using converted
trading tankers existed in the late 1960s. The first such vessels
were connected by hawsers to catenary anchor leg mooring
(CALM) systems.
These then evolved into the now more familiar systems
employing single-point mooring, where the FSO Ifrikia was
permanently moored to a buoy via a rigid arm (rather than a
hawser) in the early 1970s, with a concomitant increase in
operational reliability and reduced downtime.
The first dedicated FPSO application offshore was by Arco
in the Ardjuna field in the Java Sea offshore Indonesia in 1976
(D’Souza et al. 1994). Interestingly, this was a concrete barge with
steel tanks, used to store refrigerated liquefied petroleum gas
(LPG) moored to a buoy using a rigid arm system in 42.7m water
depth. The first tanker-based single-point moored FPSO facility
for oil is said to be the Castellon for Shell offshore Spain in 1976.
This facility was meant to produce oil from a subsea completed
well, some 65 km offshore Tarragona. It began operations in 1977,
and was designed for a 10-year field life.
Compared to these early days, floating production systems
have now evolved to a mature technology that potentially opens up
the development of offshore oil and gas resources that would be
otherwise impossible or uneconomical to tap. The technology now
enables production far beyond the water-depth constraints of
fixed-type offshore platforms and provides a flexible solution for
developing short-lived fields with marginal reserves and fields in
remote locations where installation of a fixed facility would be
difficult.
Generally ship shaped floaters with provisions for storing
and offloading of oil simultaneously. They may be designed to
weathervane so that they always face the weather, minimising roll
and heave motions. In benign environments such as West Africa
and South East Asia, the FPSO may be spread moored to face one
direction at all times.
Some FPSOs for Brazil have been designed to semi-
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