Stationary offshore terminal facilities utilizing former trading tankers were employed by the oil industry as early as fifteen years ago.
Initially, a tanker was simply connected to a single point mooring (CALM) by conventional hawsers where it served as a combination buffer storage vessel and mooring platform for shuttle tankers. Operational restrictions survival characteristics and high operating costs stimulated the development of the single buoy storage (SBS) and single anchor leg storage (SALS) systems employing rigid arms for permanently mooring the vessel to the SPM.
The first terminal of this type became operational in 1973 and it along with half a dozen similar terminals has served efficiently for many years.
In August 1977, a further step in the evolutionary process was taken with the startup of a tanker-based, rigid-arm-moored (SALS) floating production Facility. This system incorporates conventional separation equipment on the vessel for producing from a single subsea-completed well. A second similar facility also producing from a single well was installed in 1980.
Recognizing the need for testing and producing independently from two or more wells and injecting into wells, a program was instigated in 1978 to develop a high pressure, multiple flow path swivel to conduct fluids between the weathervaning vessel and the non-rotating buoy or riser. In August 1981, a facility went into operation using this new high-pressure, multiple flow path swivel producing from the subsea-completed wells in the Philippines. Philippines. More recently, a floating production, storage and offloading (FPSO) facility that can accommodate up to eight wells became operational in November, 1982.
The latter system, incorporating a 210 000 dwt vessel permanently moored in 140 metres, accommodated five production wells and three water injection wells by means of highly engineered riser, swiveling and manifolding techniques.
In the present paper, the author describes in detail four existing tanker-based floating production systems and traces their evolutionary development through stages of increasing capacities and complexity.
Also described is the progress made in perfecting vessel mooring and fluid transfer technologies which were critical pacing factors enabling realization of the tanker-based floating production concept.
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