Flexible Riser 3D Wave Configuration for Shallow Water Offset
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Solution Overview
Problem
Traditional flexible riser systems for shallow water are not offset-friendly, leading to excessive bending, overstretching, and interference with mooring or buoyancy devices, particularly in waters shallower than 40 meters, due to their two-dimensional wave configuration.
Innovation Solution
A flexible elongate element configured with lateral displacement devices, such as tethers and spring means, to create a three-dimensional wave configuration, allowing for greater offset flexibility and vertical control, which includes seabed anchor means and buoyancy members to suspend the element above the seabed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional two-dimensional wave configuration is used, then the riser can be installed in shallow water, but it causes excessive bending, overstretching, and interference with mooring or buoyancy devices
Solution Approach 1:
The patent transitions from a traditional two-dimensional wave configuration to a three-dimensional wave configuration by introducing lateral displacement devices that can displace the flexible elongate element in lateral directions. This dimensional change allows the riser to accommodate larger offsets while distributing mechanical stresses more effectively, thereby reducing excessive bending and overstretching in shallow water installations.
Solution Approach 2:
The invention employs dynamic lateral displacement devices including spring means and damper means that can actively adjust and respond to environmental loads. These devices provide dynamic compliance, allowing the riser system to adapt to varying wave conditions, currents, and vessel motions, thus preventing excessive bending and overstretching while maintaining offset flexibility.
2Reliability
If traditional riser systems are used, then the structure can support oil and gas operations, but it requires heavy mooring systems due to strict offset tolerances
Solution Approach 1:
The patent changes the configuration parameter from two-dimensional to three-dimensional wave formation, which fundamentally alters the mechanical behavior of the riser system. This parameter change increases the system's natural compliance and ability to accommodate offsets, thereby reducing the need for heavy mooring systems while maintaining reliability and stability in shallow water operations.
Solution Approach 2:
The lateral displacement devices act as intermediary elements between the flexible elongate element and the environment. These devices mediate the interaction by providing controlled lateral displacement and compliance, reducing the direct transmission of environmental loads to the mooring system, thus enabling lighter mooring configurations while maintaining system reliability.
3Adaptability or versatility
If lateral displacement devices with spring means are added, then offset flexibility increases, but device complexity increases
Solution Approach 1:
The patent divides the flexible elongate element into multiple segments with lateral displacement devices positioned at different locations along its length. Each segment can independently displace laterally, providing distributed compliance and offset accommodation capability. This segmentation approach increases adaptability while managing complexity through modular, standardized device units.
Solution Approach 2:
The lateral displacement devices are designed as multi-functional components that simultaneously provide lateral displacement, spring compliance, and damping capabilities. By integrating multiple functions into single devices, the patent increases offset accommodation capability while minimizing the increase in overall device complexity.
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 3D wave configuration enables flexible risers to accommodate larger offsets in shallow water, maintaining stability in high sea currents and allowing for variations in internal product density, while reducing installation tolerances and enabling the use of lighter materials.
Implementation Method 1
spring means
Implementation Method 2
buoyancy members
Data Source
AI summary
A flexible elongate element for installation in a body of water to extend between a seabed connection device and a unit arranged at the opposite end of the flexible elongate element. At least one lateral displacement device is connected to a portion of the flexible elongate element and configured to displace at least a portion of the flexible elongate element a lateral distance away from a first axis extending between the seabed connection device and the unit, the at least one lateral displacement device including a spring member. The flexible elongate element may be a flexible riser, umbilical, hose, or cable.