Shallow Water Seabed Terminal Pile Foundation Design
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Solution Overview
Problem
Current solutions for storing and loading hydrocarbons like LNG at sea face challenges such as high costs, complexity, and instability in shallow waters with soft seabed soils, as well as difficulties in withstanding extreme weather conditions and varying seabed conditions, leading to inefficient and costly infrastructure.
Innovation Solution
A shallow seabed terminal with a removable seabed substructure supported by piles, allowing for a stable and flexible foundation without the need for downward protruding skirts, enabling the transfer of large vertical loads and resisting uplift forces, and allowing for easy installation and expansion in various seabed conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gravity based structure (GBS) is used for storing liquids in shallow waters, then large volumes of fixed ballast are required to secure positive ground pressure, but this increases the GBS volume and weight, which in turn increases uplift forces during storm surges, necessitating additional ballast volumes, creating a negative design effect spiral that makes the solution very costly
Solution Approach 1:
The patent extracts the ballast function from the gravity-based structure by introducing a separate, adjustable ballast system. The ballast can be added or removed as needed, rather than being fixed permanently in the structure. This allows the structure to maintain positive ground pressure when required while avoiding the need for excessive fixed ballast volume that would otherwise be needed to counteract storm surge uplift forces.
Solution Approach 2:
The patent introduces dynamic adjustability to the ballast system, allowing it to change its state based on operational requirements and environmental conditions. The ballast can be adjusted to provide sufficient weight for positive ground pressure during normal operation, but can be reduced or removed when storm surge risks are present, thereby avoiding the negative design spiral of continuously adding ballast to counteract maximum possible uplift forces.
2Adaptability or versatility
If a GBS is equipped with suction skirts to make it feasible for use in soft and unconsolidated seabed soils, then the size and vertical height of the skirt solution increase, but this makes the foundation solution prohibitively expensive
Solution Approach 1:
The patent extracts the skirt element from the traditional GBS design and replaces it with a pile-supported structure. Instead of using large suction skirts to anchor the structure in soft seabed soils, the invention uses discrete piles driven into the seabed to provide foundation support. This eliminates the need for large, expensive skirt structures while maintaining adaptability to various seabed conditions.
Solution Approach 2:
The patent segments the foundation system into discrete, individual piles rather than using a continuous skirt structure. This segmentation allows for more flexible adaptation to varying seabed conditions, as each pile can be independently positioned and sized according to local soil characteristics, avoiding the need for large, monolithic skirt structures that are prohibitively expensive.
3Object-affected harmful factors
If large, rectangular steel or concrete structures are installed on the seabed to function as artificial harbours with continuous walls for wave protection, then the structures can shield vessels from waves during loading operations, but these large constructions must be built away from populated areas and require significant space
Solution Approach 1:
The patent segments the wave protection function into multiple smaller, modular units rather than requiring one large continuous structure. Each unit can be independently positioned to provide wave shielding, and the modular nature allows for flexible configuration that protects vessels without requiring a large overall construction area. This segmentation enables wave protection while minimizing the footprint and allowing closer proximity to populated areas.
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 provides a cost-effective, versatile, and flexible terminal that can handle large vertical loads, resist extreme weather conditions, and be easily installed in diverse seabed environments, reducing construction time and costs while ensuring safe and efficient hydrocarbon storage and transfer operations.
Implementation Method 1
a floatable, removable storage module... provided with buoyancy devices
Implementation Method 2
supported by a seabed by means of piles
Implementation Method 3
transfer of large vertical loads
Data Source
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AI summary
The publication relates to a shallow water seabed terminal (40) for storing and loading or unloading hydrocarbons, such as LNG, oil or gas, comprising a floatable, removable module (20), and a removable seabed substructure (10) intended to be supported by a seabed (19), the floatable module (20) being releasably fixed to the seabed substructure (10) so that a harbour terminal is formed, the seabed substructure (10) comprises a base structure (11) provided with buoyancy devices, an upwards extending wall structure (12) extending up from the base structure (11) and arranged along at least a part of the periphery of the base structure (11), the base structure also being provided with an opening (18) in the wall structure (12) for allowing the floatable module (20), to be berthed in and supported by the seabed substructure (10). The base structure (11) is provided with a submerged beam or base slab structure (35) extending laterally out from the vertical wall structure (12), configured to support the floatable, removable module, the beam or slab structure (35) being provided with sleeves or ducts extending through the submerged beam or slab structure (35) configured to receive the piles to be driven down into the seabed soil.