Semi-Submersible Hull Layout for Stable Offshore Topside Lifting
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Solution Overview
Problem
Current systems for decommissioning offshore infrastructure face challenges in efficiently and safely removing large components like topsides and jackets due to limited operational windows and potential damage during lifting, especially in rough seas.
Innovation Solution
A semi submersible vessel with a unique hull configuration and movable support beams allows for stable lifting and transportation of large offshore infrastructure components, featuring a column-stabilized design for improved motion characteristics and a receiving section for secure engagement and separation of topsides and jackets, utilizing winches and cranes for precise manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If two large vessels (VLCC) are connected to receive and support topsides between them, then the lifting capacity is sufficient for entire topsides, but the operational window is limited due to difficulty in finding sufficient steady time during movement through water
Solution Approach 1:
The vessel is divided into multiple hull portions (first hull portion, second hull portion, and central hull portion) that collectively define a receiving section. This segmentation allows the vessel to maintain stability while providing sufficient lifting capacity for entire topsides, resolving the contradiction between lifting capacity and operational reliability.
2Power
If large ship-based or barge-based cranes are used to hoist infrastructure parts, then the lifting capability is provided, but the infrastructure parts are lifted from seabed/sea level at an angle and rotated onto their side, resulting in damage and posing risk of mishap
Solution Approach 1:
Instead of lifting infrastructure parts from below at an angle and rotating them, the movable support beams extend horizontally into the receiving section to engage and support the infrastructure parts in their original orientation. This inverted approach eliminates the harmful rotation and angling that cause damage, while still providing the necessary lifting capability.
3Adaptability or versatility
If current decommissioning systems are used, then infrastructure removal is possible, but the systems are not suitable for removing large topsides and require combination with other systems
Solution Approach 1:
The vessel is designed with universal functionality to handle various offshore infrastructure components including large topsides, jackets, and other platform parts. The combination of the receiving section and movable support beams creates a multi-functional system that can independently perform separation, lifting, and transportation operations, eliminating the need to combine multiple specialized systems and thereby improving productivity.
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 vessel provides a robust and efficient method for lifting and transporting offshore infrastructure components, enhancing operational windows in rough seas and reducing the risk of damage, with the ability to handle up to 30,000 metric tonnes and ensuring stable engagement and separation.
Implementation Method 1
A semi submersible vessel with a unique hull configuration and movable support beams allows for stable lifting and transportation of large offshore infrastructure components, featuring a column-stabilized design for improved motion characteristics
Data Source
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AI summary
A semi submersible vessel for manipulating offshore infrastructures, the vessel comprising: a first hull portion; a second hull portion, laterally spaced from the first hull portion; a central hull portion connecting the first and second hull portions; wherein the first hull portion, second hull portion and central hull portion collectively define an open receiving section for receiving an offshore infrastructure or a part thereof into between the first hull portion and second hull portion; and each of the first and second hull portions comprises a plurality of laterally movable support beams arranged to extend from the respective hull portion into the receiving section for supporting an offshore infrastructure or a part thereof; wherein at least one of the support beams of the first hull portion and one of the support beams of the second hull portion comprises a winch system for hoisting part of an offshore infrastructure located in the receiving section. A method of manoeuvring topsides or a part of an offshore infrastructure or installing topsides or a part of an offshore infrastructure using the semi submersible vessel.