Hybrid Riser Composite Conduits Buoyancy Segmentation
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Solution Overview
Problem
Hybrid riser systems face challenges with weight, buoyancy, insulation, and structural interactions, particularly in deep water, due to the use of syntactic buoyancy material and high axial stiffness of peripheral lines, which limits their applicability and increases complexity and cost.
Innovation Solution
The hybrid riser system employs composite fluid conduits made of a matrix with embedded reinforcing elements, providing near-neutral buoyancy, reduced weight, improved thermal characteristics, and increased strain rates to accommodate axial and lateral deformations, eliminating the need for complex buoyancy materials and allowing for greater water depth utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If syntactic buoyancy material is used to support peripheral lines, then buoyancy is provided, but the material is very expensive and requires specialised insulation materials in addition
Solution Approach 1:
The patent applies composite materials by integrating insulation directly into the buoyancy module structure. The buoyancy modules are made from composite materials that provide both buoyancy and thermal insulation properties simultaneously, eliminating the need for separate specialised insulation materials while reducing overall system complexity and cost
2Stability of the object's composition
If syntactic buoyancy material is used, then buoyancy is achieved, but the upper aircan becomes excessively large making it difficult to fabricate, launch and handle
Solution Approach 1:
The patent divides the buoyancy system into multiple smaller buoyancy modules distributed along the riser length rather than relying on a single large upper aircan. This segmentation provides the required buoyancy support while keeping each module compact and manageable, significantly improving ease of fabrication, launch, and handling operations
3Adaptability or versatility
If peripheral lines are allowed to slide axially with respect to the central structural pipe, then axial movement is accommodated, but the true wall tension in the central pipe may be prohibitive limiting the weight and number of peripheral lines
Solution Approach 1:
The patent introduces guide structures as intermediary elements between the peripheral lines and the central structural pipe. These guide structures constrain the axial movement of peripheral lines relative to the central pipe, preventing excessive sliding while distributing and reducing the wall tension forces in the central pipe, thereby allowing heavier and more numerous peripheral lines
4Force
If the peripheral lines are constrained to prevent axial movement, then wall tension is reduced, but the high axial stiffness generates high tension and compression that can damage buoyancy modules and other fittings
Solution Approach 1:
The patent implements a dynamic solution where guide structures allow controlled axial movement of peripheral lines within defined limits. This dynamic approach balances the conflicting requirements by permitting sufficient movement to avoid excessive wall tension while constraining movement enough to prevent damaging tension and compression forces, protecting buoyancy modules and fittings from damage
5Length of moving object
If the riser system is designed for deep water, then water depth utilization is improved, but the aircan becomes excessively large and structural interactions become more complex
Solution Approach 1:
The patent applies segmentation by distributing buoyancy throughout the riser system using multiple buoyancy modules along the length rather than concentrating buoyancy in a single large aircan. This approach enables deep water application by providing continuous buoyancy support, reducing the size and complexity of individual components while maintaining structural integrity at greater depths
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
This solution reduces the volume and weight of buoyant structures, minimizes thermal losses, and enhances structural integrity, enabling the hybrid riser system to operate effectively in deeper waters with reduced complexity and cost, while accommodating thermal and pressure-induced deformations within yield limits.
Implementation Method 1
the composite fluid conduits may be configured with near neutral buoyancy when the lines are air filled in-water
Implementation Method 2
this can be insufficient due to hot water convection losses in the water gap (Figure 1) between the lines (14) and the buoyancy material (16)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A hybrid riser system comprises a lower riser section secured between a lower subsea anchor and an upper buoyant structure, and an upper riser section extending between the lower riser section and a surface or near surface vessel. The lower riser section comprises an elongate support and one or more composite fluid conduits secured to and extending adjacent the elongate support. The composite fluid conduits comprise a composite material formed of at least a matrix and one or more reinforcing elements embedded within the matrix. The upper riser section comprises one or more flexible conduits in fluid communication with the composite fluid conduits.