Patent ID: 8702350

Claim:
A riser assembly for transporting production fluids such as oil, gas and/or water from a sub-sea flow line to a floating structure, comprising: plural segments of flexible pipe each of which is formed as a composite structure of two or more unbonded layers, the layers including an internal sheath for ensuring fluid integrity and a pressure armour layer provided over the internal sheath for resisting internal and external pressure; and a rigid buoyancy support having at least one buoyancy element at said support, wherein said buoyancy support comprises a rigid pipe member connected at a first and second end thereof in an in-line configuration to an end fitting of two of the plural segments of flexible pipe; wherein the rigid buoyancy support comprises a plurality of rigid buoyancy supports spaced apart along the length of the riser assembly, each rigid buoyancy support for supporting at least one buoyancy element, and each rigid buoyancy support being connected in an in-line configuration to a respective pair of segments of flexible pipe; wherein the plural segments of flexible pipe are relatively more flexible than the rigid pipe members of the rigid buoyancy supports; wherein all of the buoyancy elements of the riser assembly are mounted on rigid pipe members.