Seabed Storage Tank Stability via Compartmental Flood Control
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Solution Overview
Problem
Offshore hydrocarbon processing is hindered by the need for large vessels to withstand sea forces, which increases costs and complexity due to the challenges of fluid and electronic signal interconnections, and the inefficiency of storing hydrocarbons on the surface where they are affected by sea motions.
Innovation Solution
A double-hull tank with compartmentalized chambers is designed for seabed storage, allowing controlled flooding and air injection to maintain stability and buoyancy, enabling safe towing and retrieval, and equipped with monitoring devices for remote operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a large vessel is used to withstand sea forces, then the vessel's strength and stability are improved, but the device complexity and cost increase due to larger mooring systems and more complex interconnections
Solution Approach 1:
The invention extracts the storage function from the surface vessel and places it on the seabed. The tank is detached from the vessel, eliminating the need for complex mooring systems and fluid/power/electronic interconnections through the swivel. The tank independently withstands sea forces on the seabed while the vessel remains agile on the surface.
Solution Approach 2:
The system is segmented into two independent components: the surface vessel and the seabed tank. This segmentation allows each component to be optimized for its specific function without the constraints of the other, eliminating the need for complex interconnections and mooring systems while maintaining operational capability.
2Stability of the object's composition
If the vessel size is increased to moderate sea motions, then the vessel's stability is improved, but the forces and loads on the mooring system increase
Solution Approach 1:
The storage function is extracted from the vessel and placed on the seabed. This eliminates the need for the vessel to be oversized for stability purposes, as the tank independently provides stable storage on the seabed. The vessel can remain smaller and more agile without bearing the burden of stability requirements.
Solution Approach 2:
By segmenting the system into vessel and tank components, the stability requirement is transferred to the tank on the seabed. The vessel is freed from stability constraints, allowing for smaller size and reduced mooring loads while the tank provides stable storage independently.
3Reliability
If the tank is designed with extensive compartmentalization for safety, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The tank is divided into multiple compartments separated by bulkheads. This segmentation provides redundancy and safety - if one compartment is breached, others remain intact. The compartmentalization is implemented in a practical manner that balances safety requirements with construction feasibility and operational simplicity.
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 tank remains stable and afloat during flooding, allowing for safe towing and controlled submersion or recovery, reducing the need for large vessels and mooring systems, thus lowering operational costs and enhancing storage efficiency.
Implementation Method 1
The hollow wall 16 is compartmentalized to form a plurality of compartments or chambers 18. The compartments 18 allow controlled flooding and evacuation of void space located between the outer and inner side walls 12 and 14, during sinking and recovery of the tank 10.
Implementation Method 2
controlled air injection into the at least one compartment and controlled water release from the at least one compartment
Data Source
Figure 1a~1b
Figure 2a~2c
AI summary
A tank for storage of hydrocarbon liquids on the seabed, being of double hull construction which is compartmented to form a plurality of chambers, such that the tank may be safely towed from its build location or shipyard, to offshore deployment location as marine warranty compliant vessel, having appropriate intact and damaged stability characteristics. There is also provided a method for deploying a tank for storage of hydrocarbon liquids on the seabed, the method comprising the step of towing the tank having un-ballasted storage areas and compartments to the location of deployment; flooding at least partially the storage area to achieve substantial neutral buoyancy of the tank to allow decent of the tank up to a submerged equilibrium; allowing decent of the tank to the seabed and injecting air into at least one compartment for maintaining equilibrium between the pressure applied by the surrounding sea and the pressure inside compartments and storage area.