Saipem Limited

Antonio Silvestri

Pasquale Brando

Guglielmo Gargatagli

A process and apparatus for installing the enbloc superstructure of an offshore platform on the fixed legs emerging from water of the lower structure or jacket including loading the whole superstructure on a vertically movable support platform provided on the deck of a semisubmersible raft or barge, completely submerging the raft in the vicinity of the jacket, the stability being maintained by vertical buoyancy tanks on the raft deck, and lifting the support platform and the superstructure by activating related hydraulic lift cylinders, to a height higher than that of the protruding ends of the jacket leg, independently from wave-motion of sea. Subsequently, cylindrical lift pillars slide, by means of hydropneumatic jacks, within tubular columns provided in the superstructure until the conical ends of the pillars enter corresponding seats in the jacket legs and, during a moment of smooth sea, the superstructure is lifted to the desired height using the hydropneumatic jacks, while at the same time, the support platform is rapidly lowered, and the raft is ballasted.

Process for the installation of the enbloc superstructure of an offshore

A method is disclosed for repairing a damaged pipe laid on deep sea beds, said method substantially comprising the step of joining a central pipe stub between the ends of the two adjoining pipe portions, such operation being performed directly on the sea bed rather than on the pipe-laying barge. Special coupling sleeves are provided at both ends of the central pipe stub, said sleeves being received in a watertight manner on the two pipe terminal portions, by clamping said sleeves thereon. Apparatus and tools for carrying out said method are described in great detail.

Method for repairing a damaged pipe laid on deep sea beds

A device for and method of supporting a section of submerged pipeline over depressed portions of the sea bed such as ditches, fissures and the like, comprising an assembly of a pipe-clamping mechanism and two or more posts associated therewith, which are drivable into the sea bottom. Hydraulically powered means also provided for manipulating the clamping mechanism and means are further provided for lowering and raising the assembly. A cheap, safe and reliable device and method are provided which is an improvement over conventional techniques which generally provide sand bags under the pipe section suspended over a depression in the sea bottom.

Apparatus for and method of supporting pipelines suspended over

A closed end of a pipeline submerged in water to a depth of upwards of about 125 meters if lifted to the surface and recovered by exerting a pull on said end by means of a capstan mounted on a floating pontoon and having an adjustable tension, and by simultaneously exerting a lift on said pipeline at said end and at least one point spaced from said end by means of a set of cranes mounted on said pontoon, at least one of said cranes being mounted for movement on said pontoon and adapted to exert a lift at said end of the pipeline, and at least one other crane being fixed to said pontoon and adapted to exert a lift at said end and at the point spaced from said end of the pipeline, so that the length of the pipeline between said point and said end may be removed from the balance of the pipeline.

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San Donato Milanese, Italy

Antonio Silvestri