Subsea Pipeline Retrieval Using Controlled Plastic Deformation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current subsea pipeline retrieval methods are costly and inefficient, requiring expensive assets to apply high tensions and thrusts, which can damage the pipeline and are environmentally undesirable, despite being the least commercially attractive option.
Innovation Solution
A method and system that involves suspending and plastically deforming a portion of the pipeline to reduce the required longitudinal tension for retrieval, allowing for the use of smaller, lower-cost vessels and minimizing structural integrity changes, by applying controlled longitudinal tensions to deform the pipeline and then straightening it for topside processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high tensions and thrusts are applied to retrieve the pipeline using conventional methods, then the pipeline can be retrieved from the seabed, but the costs increase significantly and expensive assets are required
Solution Approach 1:
The patent changes the physical state of the pipeline from rigid to plastically deformable during retrieval. By applying controlled plastic deformation, the pipeline can be retrieved with lower tensions and thrusts, eliminating the need for expensive heavy-lift vessels and reducing operational costs while maintaining retrieval reliability
Solution Approach 2:
Instead of trying to pull the heavy pipeline straight up from the seabed using high tension (conventional approach), the patent inverts the approach by allowing the pipeline to plastically deform and bend during retrieval, using gravity and controlled deformation to reduce the required retrieval forces
2Reliability
If high tensions are applied to retrieve the pipeline, then the pipeline can be pulled to the surface, but the structural integrity of the pipeline may be compromised
Solution Approach 1:
The patent changes the mechanical properties consideration from maintaining rigid structural integrity to allowing controlled plastic deformation. By managing the deformation parameters, the pipeline can be retrieved without exceeding material limits that would cause failure, while the plastic deformation itself reduces retrieval tensions
Solution Approach 2:
The patent applies plastic deformation as a cushioning mechanism before the final retrieval stage. This pre-deformation reduces the peak tensions and thrusts that would otherwise be required, protecting the pipeline from structural damage during the critical retrieval phases
3Reliability
If conventional retrieval methods are used, then the pipeline can be retrieved, but larger vessels with higher thruster loads are required
Solution Approach 1:
The patent changes the force requirements by introducing plastic deformation as an intermediate state. This reduces the peak forces and thrusts needed during retrieval, allowing smaller vessels with lower thruster capacities to perform the retrieval operation successfully
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
This approach reduces retrieval costs by using lower tension loads, allows for longer pipe sections to be cut at the surface, minimizes slippage and thruster loads, and can handle coated pipelines without compromising their integrity, making the process more environmentally friendly and economically viable.
Implementation Method 1
plastically deforming said portion of the pipeline to form a plastically deformed portion
Data Source
AI summary
A method for retrieving a pipeline from a seabed in the body of water to a vessel includes the steps of suspending at least a portion of the pipeline in the body of water between the seabed and the vessel, plastically deforming the portion of the pipeline to form a plastically deformed portion, and retrieving the plastically deformed portion to the vessel.