Subsea Pipeline Direct Tie-In With Preferential Bending Pullback
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Solution Overview
Problem
Existing direct tie-in methods for subsea pipelines require large forces and risk damage due to the need for route curves or residual curvature sections, especially in deep water operations, and involve high installation costs from separate jumpers or spools.
Innovation Solution
A method where the pipeline is laid with the first section beyond the tie-in position, and the second section is configured to preferentially induce bending when the first section is pushed or pulled back, using mechanisms like hydraulically driven pistons, buoyancy adjustments, or vessel/ROV assistance to minimize the need for route curves and reduce required forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If route curves or residual curvature sections are introduced to provide flexibility for pull-in, then the pipeline can be pulled close to the subsea structure, but large forces are required which risk damage to the pipeline and/or subsea structure
Solution Approach 1:
The pipeline is pre-configured with a specific curvature profile during manufacturing or installation that anticipates the pull-in operation. This preliminary shaping allows the pipeline to naturally flex into position without requiring excessive force during the actual tie-in operation, thereby preventing damage while enabling the pull-in maneuver.
Solution Approach 2:
The invention modifies the physical parameters of the pipeline by introducing controlled curvature sections with specific radii and lengths. These parameter changes create a flexible zone that can accommodate the pull-in movement, reducing the peak forces required and distributing the mechanical stress away from critical connection points.
2Ease of manufacture
If separate jumpers or spools are used to connect the pipeline to the subsea structure, then the tie-in can be completed, but the extra components and procedures result in high costs for the installation process
Solution Approach 1:
The invention merges the pipeline with the subsea structure by providing engagement features directly on the pipeline itself, eliminating the need for separate jumper pipes or spool pieces. This integration reduces the number of components and simplifies the tie-in procedure while maintaining secure mechanical connection.
Solution Approach 2:
The invention extracts and removes the intermediate connection components (jumpers and spools) from the tie-in system. By providing direct engagement features on the pipeline, the solution eliminates unnecessary components and reduces installation complexity while achieving the same functional result.
3Ease of operation
If the pipeline is laid in a curve or with residual curvature to enable pull-in, then flexibility is provided, but in deep water operations it is challenging to introduce route curves or install residual curvature sections due to the length of the pipeline in the water column
Solution Approach 1:
The desired curvature is incorporated into the pipeline during manufacturing or pre-installation phases, rather than attempting to install it in-situ during the deep water operation. This preliminary configuration ensures the flexibility features are already in place before the challenging deep water deployment, avoiding the difficulty of manipulating long pipeline sections in the water column.
Solution Approach 2:
The invention employs curved or bent sections of pipeline with specific geometric profiles that provide the necessary flexibility for pull-in operations. These curved sections are strategically positioned to create a flexible zone that enables the tie-in maneuver without requiring complex in-situ manipulation during deep water installation.
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 the risk of pipeline and subsea structure damage, lowers installation costs, and simplifies the tie-in procedure by eliminating the need for distant route curves, especially in deep water environments.
Implementation Method 1
The mechanism comprises hydraulically driven pistons
Implementation Method 2
configuring the second section such that bending will be preferentially induced in the second section of the at least a portion of the pipeline when the first section is pushed or pulled back to the tie-in position
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A method of installing a subsea pipeline having a direct tie-in between a first section of the pipeline and a subsea structure, wherein, after installation, the first section is located at a tie-in position. The method comprises: laying at least a portion of the pipeline from a laying vessel, the at least a portion of the pipeline including the first section and a second section of the pipeline, such that the first section is beyond the tie-in position in the laying direction, and the first section and the tie-in position are beyond the second section in the laying direction; either before, during or after said laying, configuring the second section such that bending will be preferentially induced in the second section of the at least a portion of the pipeline when the first section is pushed or pulled back to the tie-in position; pushing or pulling the first section back to the tie-in position, wherein, responsive to said pushing or pulling, bending is preferentially induced in the second section.