Segmented Buoyancy Compensator for Flexible Pipe Tension Management

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Solution Overview

Problem

Flexible pipes in subsea applications face challenges with high tension loads due to internal pressure and self-weight, leading to potential failure, and existing buoyancy aids can cause compression loads and are difficult to handle and install, while bend stiffeners are cumbersome for transportation and installation.

Innovation Solution

A buoyancy compensating element comprising two connectable body portions that encompass a flexible pipe, attachable at a midline connection to adjust buoyancy without exerting compression loads, allowing for easier handling, installation, and integration of bend limiting features to prevent overbending.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If buoyancy aids are added at predetermined locations along the riser, then the upward lift to counteract the weight of the riser is improved, but the compression loads on the flexible pipe and difficulty of installation increase

Engineering Contradiction:
Improveupward liftVSAvoidinstallation difficulty
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The buoyancy compensating element is divided into a first body portion and a second body portion that can be separately transported and then connected together. This segmentation allows the elements to be handled more easily during installation while still providing the required buoyancy force when assembled.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The buoyancy compensating element acts as an intermediary component that connects to the flexible pipe through a coupling mechanism. This intermediary structure provides the buoyancy force while isolating the compression loads from the flexible pipe itself, and the split design allows for easier attachment and adjustment.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If rigid buoyancy supports are used to provide a rigid surface for affixing buoyancy aids, then crushing of the flexible pipe is avoided, but the device complexity increases

Engineering Contradiction:
Improveprotection from crushingVSAvoidstructure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The rigid protective surface is provided only at the specific locations where buoyancy aids need to be affixed, rather than making the entire buoyancy compensating element rigid. The first and second body portions can be made of flexible material with localized rigid surfaces or reinforcement only where needed for attachment, maintaining overall flexibility while providing local protection.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The first and second body portions are designed as asymmetric or complementary shapes that fit together to form the complete buoyancy compensating element. This asymmetric design allows for simplified manufacturing and assembly while providing the necessary rigid surface area for affixing buoyancy aids when connected.

Inventive Principle:
Principle #4Asymmetry

3Force

If buoyancy compensating elements are attached to the flexible pipe, then the tension loads are reduced, but the handling and installation before attachment becomes more difficult

Engineering Contradiction:
Improvetension load reductionVSAvoidinstallation time
Core Design Contradiction:
ForceVSLoss of time

Solution Approach 1:

By dividing the buoyancy compensating element into separable first and second body portions, the system allows for easier transportation and handling of individual components. The portions can be moved separately and then quickly connected together and to the flexible pipe, reducing overall installation time compared to handling a single large assembled unit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first and second body portions can be prepared and positioned in advance at convenient locations, and then connected together and attached to the flexible pipe when ready. This preliminary preparation reduces the complexity and time of the actual attachment operation.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enables easier handling and installation of flexible pipes by allowing separate transportation and attachment of buoyancy compensating elements, reduces compression loads, and eliminates the need for additional bend stiffeners, thereby enhancing the flexibility and durability of the pipe assembly.

Implementation Method 1

a buoyancy compensating element or elements, and a method of providing the same... for providing buoyancy to reduce tension

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentEP2785950B1Buoyancy compensating element and method
Publication Date: 2017.03.01 BAKER HUGHES ENERGY TECHNOLOGY UK LTD
  • EP2785950B1 patent drawingFigure 1~2
  • EP2785950B1 patent drawingFigure 3~4
  • EP2785950B1 patent drawingFigure 5~6

AI summary

A buoyancy compensating element (500) for connection to a flexible pipe (520) and method of producing a buoyancy compensating element are disclosed. The buoyancy compensating element (500) includes a first body portion (502) and a further body portion (504), wherein the first and further body portion are configured to be connectable to each other and in use to encompass a portion of flexible pipe (520).