A method and system for sea-based handling/treatment of fluid hydrocarbons (oil)
with associated gas include a first separation step in a high-pressure separator
(18) installed on the sea bed, from which is output an oil flow containing
an essentially predefined percentage of residual gas. The oil containing residual
gas is carried through a riser (22) up to a surface vessel/production ship
(12), where it is subjected to a second separation step in a second separator
(24) incorporated in a low-pressure surface plant on board the vessel (12),
this separated residual gas being used as fuel for direct/indirect generation of
electric power for the operation of the underwater and above-water sections of
the system. Water and gas produced in the first separation step is returned to
a suitable reservoir by the use of a multiphase pump.
