Platform Assembly Tensioning System for Well Riser Stability
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Solution Overview
Problem
Conventional monohull sea vessels face challenges in stabilizing platforms during vessel movement, leading to safety risks for workers and potential damage to risers due to inadequate tension distribution and large moon pool requirements, with existing solutions being heavy, space-consuming, or hazardous.
Innovation Solution
A platform assembly with a tensioning system using flexible tension members and hydraulic cylinders to maintain uniform tension and accommodate angular movements, eliminating the need for a gimbal mechanism and allowing the platform to pivot, while being restrained against movement in specific axes to maintain stability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a large tension frame is used to accommodate larger tools, then the working area capacity is improved, but the moon pool size requirement increases and stability becomes more difficult to maintain
Solution Approach 1:
The patent applies a dynamic stabilization system where the platform can pivot and rotate to follow vessel movements, and the tensioning system actively adjusts wire lengths to maintain constant tension. This dynamic adaptation allows the platform to remain stable and level despite vessel pitch and roll, enabling larger working areas without compromising stability or requiring larger moon pools.
2Area of stationary object
If a gimbal device is used to stabilise the platform, then the moon pool size is reduced, but the device becomes heavy and space-consuming
Solution Approach 1:
The patent segments the stabilization function into two independent parts: (1) a pivot connection that allows the platform to follow vessel angular movements, and (2) a tensioning system with adjustable wire lengths that maintains constant tension. This segmentation eliminates the need for a single heavy gimbal mechanism while achieving the same stabilization effect, reducing weight and space requirements.
3Device complexity
If the platform is fixed relative to the vessel, then the structure is simpler, but the riser experiences damaging bending torques during vessel movement
Solution Approach 1:
The patent implements a dynamic connection where the platform is not rigidly fixed to the vessel but can pivot and rotate to follow vessel movements. The tensioning system dynamically adjusts wire lengths to maintain constant tension, allowing the platform to move with the vessel without creating bending torques on the riser, thus protecting the riser while maintaining structural simplicity.
4Stability of the object's composition
If the platform rotates about the hook connection, then the bottom of the tension frame remains aligned with the riser, but the tension distribution becomes uneven during vessel movement
Solution Approach 1:
The patent incorporates a feedback mechanism where the tensioning system continuously monitors and adjusts wire lengths to maintain constant tension on the riser. This active control compensates for changes in platform orientation and vessel movement, ensuring uniform tension distribution while maintaining riser alignment, thus resolving the contradiction between alignment stability and tension uniformity.
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 safer working area by maintaining uniform tension and reducing bending moments on the riser, allowing for a smaller moon pool and increased maneuverability, while avoiding the need for heavy and space-consuming gimbal devices, thus enhancing worker safety and reducing the risk of damage.
Implementation Method 1
The tensioning means comprises a plurality of hydraulic cylinders connected between the platform and the derrick
Implementation Method 2
The tensioning means comprises flexible tension members extending from the derrick to the platform
Data Source
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AI summary
A platform assembly (10) for providing a work area around a well riser (16) is disclosed. The platform assembly (10) comprises a platform (26) configured to be attached to the well riser (16). The platform assembly (10) further comprises a plurality of tensioning means (28) for supporting the platform (26) relative to a vessel (14) and for supporting the riser (16). At least part of tensioning means (28) is configured to change in length relative to another part of tensioning means (28) responsive to angular motion of the riser (16) and the vessel (14).