Distributed buoyancy

The use of flexible pipe in offshore oil and gas production is usually grouped into two categories; static and dynamic. Dynamic applications normally involve an offshore floating production facility or terminal connected to another floating facility or fixed structure.

Flexible pipe and umbilicals require the use of buoyancy modules to reduce topside or tension loads to achieve particular configurations which include lazy, steep, pliant and W-wave.

BOE distributed buoyancy modules generally consist of an internal clamping system and syntactic foam buoyancy elements. The buoyancy elements are supplied in two halves incorporating a moulded internal recess that is configured to transfer the forces from the buoyancy to the clamp and subsequently the riser. This recess also accommodates bending of the riser during service. The internal clamping system is fixed to the pipe and the two half modules are fastened around the clamp.

Deepwater projects require modules and clamps to be designed for operating depths in excess of 3000msw where substantially larger modules and extreme clamping loads are demanded. BOE has been driving a significant R&D programme to meet this challenge and has developed a number of solutions for deep and ultra-deepwater environments.

Typical distributed buoyancy configurations
Lazy wave Steep wave W-wave