Controlling Buoyancy When Towing, Lowering and Raising Submerged Structures
AssigneeAcergy France SAS
InventorMarcel Marco Landwehr
Life of this patent
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Abstract
A subsea structure comprises: an elongate articulated buoyancy string comprising a longitudinal series of buoyancy elements; and at least one elongate buoyancy holder that is fixed relative to the structure and is capable of housing the buoyancy string. The buoyancy of the structure may be altered by moving the buoyancy string along a transit path that extends along and within the buoyancy holder and through an end opening of the buoyancy holder. The buoyancy string passes through that end opening on being inserted into or withdrawn from the buoyancy holder.
Claims33
A subsea structure in combination with:
- an elongate articulated buoyancy string comprising a longitudinal series of buoyancy elements;
- and
- at least one elongate buoyancy holder that is capable of housing the buoyancy string, the buoyancy holder being fixed relative to the subsea structure.
The structure of claim 2, wherein the buoyancy holder defines a transit path for movement of the buoyancy string along and within the buoyancy holder.
The structure of any preceding claim, wherein the buoyancy holder is tubular.
The structure of any preceding claim, wherein a side wall of the buoyancy holder is penetrated by one or more lateral openings.
The structure of any preceding claim, comprising a plurality of said buoyancy holders.
The structure of any preceding claim, wherein the or each buoyancy holder is connected rigidly to the remainder of the subsea structure.
The structure of any preceding claim, wherein the or each buoyancy holder is integrated with the subsea structure.
The structure of any preceding claim, wherein the or each buoyancy holder is longer than at least one buoyancy element of the buoyancy string.
The structure of any preceding claim, wherein the buoyancy elements are rigid.
The structure of any preceding claim, wherein the buoyancy elements are solid blocks.
The structure of any preceding claim, wherein the buoyancy elements have a friction-reducing coating.
The structure of any preceding claim, wherein the buoyancy elements are each connected to the or each neighbouring buoyancy element in the series by a link that permits relative angular movement between neighbouring buoyancy elements.
The structure of any preceding claim, being a pipeline bundle along which the or each buoyancy holder extends.
A method of altering the buoyancy of a subsea structure, the method comprising moving an elongate articulated buoyancy string of buoyancy elements along a transit path extending along and within an elongate buoyancy holder that is fixed relative to the structure, wherein the transit path extends through an end opening of the buoyancy holder and the buoyancy string passes through that end opening.
Dependencies are inferred from the claim text.