Abstract: 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.

Abstract: A method and system for sea-based handling/treatment of fluid hydrocarbons (oil) with associated gas comprise 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.

Abstract: A method for determining the position of a marine seismic receiver cable of the type which is towed behind a seismic survey vessel through the sea, wherein the azimuth and the distance from the vessel to points along the seismic receiver cable are measured, and the coodinates of these points are calculated on the basis of these values. A hydroacoustic measurement method is utilized, based on a super-short baseline system integrated with a gyrocompass, for measuring the azimuth and distances in accordance with signals from transponders, beacons, responders and/or similar instruments installed on or within the seismic receiver cable.