Buoyant Connector Mass Reduction in Deepwater Riser-Mooring Systems
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Solution Overview
Problem
Existing hydrocarbon production installations with connection buoys in deep sea environments face challenges in minimizing the mass and volume of the buoyant connector, making it difficult to manipulate and move during disconnection and reconnection processes, which are crucial for efficient operation and safety.
Innovation Solution
The design features a buoyant connector that is not directly moored to the seabed, with flexible jumper hoses supporting the riser buoys, allowing the connector to sink under the wave action zone and reducing the weight that needs to be lifted during reconnection, using primarily horizontal mooring lines and flexible jumper hoses to minimize the mass and volume of the connector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the connector is made more massive to increase its buoyancy and stability, then it can better support the risers and mooring lines, but it becomes harder to manipulate and move during disconnection and reconnection
Solution Approach 1:
The system divides the support function into separate components: mooring buoys support the mooring lines while riser buoys support the risers, with the connector only needing to support its own weight and half the jumper hose weight. This segmentation allows each component to be optimized independently for its specific function.
Solution Approach 2:
Riser buoys act as intermediary elements between the seabed and the connector, providing support for the risers without requiring the connector to bear their full weight. The flexible jumper hoses serve as intermediaries that transmit only minimal forces to the connector.
2Ease of operation
If the connector is made lighter to ease manipulation during disconnection and reconnection, then it becomes easier to handle, but it may not have sufficient buoyancy to support the risers and mooring lines reliably
Solution Approach 1:
The support function is segmented between multiple buoys (mooring buoys and riser buoys) rather than relying on the connector alone. This allows the connector to be lightweight while the distributed buoyancy system maintains overall reliability.
Solution Approach 2:
The system uses buoyant forces from multiple buoys to counterbalance the weights of the risers and mooring lines, distributing the load rather than concentrating it on the connector. The flexible jumper hoses provide additional buoyancy support.
3Reliability
If the connector is moved a longer distance during disconnection and reconnection, then it can be positioned deeper under the wave action zone for safety, but it requires more effort to manipulate and move
Solution Approach 1:
The system allows the connector to sink to a depth where it is under the wave action zone for safety, while the flexible jumper hoses and buoyant riser buoys compensate for the increased depth, making the connector's position effectively equipotential in terms of manipulation effort.
Solution Approach 2:
The system changes the physical parameters of the jumper hoses (making them flexible and buoyant) and the riser buoy means (making them separate from the seabed) to allow the connector to be positioned deeper while maintaining ease of manipulation through parameter modifications.
4Stability of the object's composition
If rigid vertical lines are used to support the risers and mooring lines, then the structure is more stable, but the connector must support more weight and becomes harder to move
Solution Approach 1:
The system replaces rigid vertical lines with flexible jumper hoses that connect the riser buoys to the connector. These flexible elements provide sufficient structural stability while distributing weight and minimizing the connector's burden, allowing it to be lighter and easier to move.
Solution Approach 2:
The system transitions from a static rigid structure to a dynamic flexible structure where the jumper hoses can adapt to movement and environmental conditions. This dynamic flexibility allows the connector to be lighter while maintaining structural integrity and stability.
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 configuration reduces the effort required for handling and moving the connector, allowing it to be lifted with minimal weight, enhancing operational efficiency and safety by minimizing the mass and volume of the connector, thus simplifying the disconnection and reconnection process.
Implementation Method 1
the connector can be disconnected from the vessel to sink under much of the wave action zone
Implementation Method 2
Flexible jumper hoses extend from the riser buoy to the connector
Data Source
AI summary
A system is described for use at offshore locations of large depth, for mooring a production vessel or floating unit (14) at a location over a hydrocarbon reservoir (26) and for connecting risers (101) that can be carrying hydrocarbons up from the sea floor to a production vessel that stores the hydrocarbons, flowlines for water injection, gas lift, gas export, umbilicals and mooring lines that moor the vessel. Both the mooring lines and the risers are disconnectably connected to the vessel though a connection buoy, or connector (16). The invention concerns a system that allows a connector (16) to be used that is of minimum mass and volume, to ease its handling especially during its connection and disconnection to and from a vessel.