Subsea Accessory Support Structure Deployment via Preliminary Placement
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Solution Overview
Problem
The restricted dimensions of pipelaying equipment on vessels limit the size of mudmats that can be deployed for in-line tees, disrupting the pipelaying process, especially with S-lay methods, which are high in lay rate but prone to interruptions when larger accessories are involved.
Innovation Solution
Deploying accessory support structures too large to pass through the pipelaying equipment by pre-installing them on the seabed or using a vessel with different pipelaying equipment, and maintaining accessories in an upright configuration with angled rollers and temporary buoyancy aids during deployment, allowing for secure clamping and guiding into cradles on the seabed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If larger accessory support structures are used, then the support capability for in-line tees is improved, but the pipelaying process is interrupted due to equipment dimension restrictions
Solution Approach 1:
The mudmat is deployed and positioned on the seabed before the pipeline laying operation. This preliminary placement allows the large accessory support structure to be in position without needing to pass through the pipelaying equipment during the actual laying process, thus maintaining lay rate while providing necessary support capability
Solution Approach 2:
The installation process is divided into separate phases: first deploying the mudmat independently, then laying the pipeline with accessories. This segmentation allows each component to be installed by the most appropriate method without constraining the other, resolving the conflict between size requirements and equipment limitations
2Length of moving object
If folding components are incorporated into the mudmat, then the dimension restriction is overcome, but the complexity and cost of the mudmat increases
Solution Approach 1:
The mudmat is deployed in its full, unfolded configuration during a preliminary deployment phase before pipeline laying begins. This eliminates the need for folding mechanisms during the critical laying operation, simplifying the mudmat design while still allowing large dimensions when needed
Solution Approach 2:
Instead of making the mudmat collapsible to pass through equipment, the solution inverts the approach by placing the mudmat on the seabed first, then bringing the pipeline to it. This reverses the traditional sequence and eliminates the need for dimension reduction mechanisms
3Length of moving object
If folding components are incorporated into the mudmat, then the dimension restriction is overcome, but the storage area required at the stern increases
Solution Approach 1:
The mudmat is deployed and positioned on the seabed before pipeline laying operations commence. This preliminary deployment eliminates the need to store large folded mudmats at the stern during laying operations, reducing storage space requirements while still allowing large mudmats to be used when needed
4Length of moving object
If folding components are incorporated into the mudmat, then the dimension restriction is overcome, but the stability of the mudmat deteriorates
Solution Approach 1:
The mudmat is deployed in its stable, unfolded configuration and positioned on the seabed before pipeline laying begins. This ensures the mudmat achieves its full structural stability and low center of gravity configuration before being used to support accessories during pipeline operations
Solution Approach 2:
Instead of folding the mudmat to pass through equipment, the approach inverts the sequence by placing the stable, unfolded mudmat on the seabed first, then bringing the pipeline and accessories to it. This maintains mudmat stability throughout the operation
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
Enables the use of larger accessory support structures without interrupting the pipelaying process, ensuring efficient and continuous pipeline deployment with reduced storage requirements and stability issues.
Implementation Method 1
maintaining accessories in an upright configuration with angled rollers and temporary buoyancy aids during deployment
Data Source
Figure 1
Figure 2
Figure 3~5B
AI summary
Methods and apparatus for deploying pipeline from a vessel are described in relation to pipelines with installed accessories. One or more accessory support structures (58) are installed at appropriate bedding locations on the seabed. In deploying pipeline from a vessel, an accessory is then attached at a position along the pipeline to correspond with the pre-installed accessory support structure bedding location. The pipeline and attached accessory are deployed and guided into engagement with the pre-installed accessory support structure (58) on the seabed such that the pipeline is deployed substantially horizontally through the accessory support structure (58) and the accessory is supported by the pre-installed accessory support structure (58) at the bedding location.