Subsea Pipeline Laying with Reinforced Sections and Internal Plugging Train

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Solution Overview

Problem

Pipelines laid on the bed of a body of water are prone to rupture due to bending stress and pressure differences, leading to costly and time-consuming damage and flooding, with existing plugging techniques being ineffective in preventing crushing and ensuring the integrity of the pipeline.

Innovation Solution

A method involving the construction of pipelines with thicker sections and a train that moves within the pipeline to prevent flooding, where the train's position is synchronized with the thicker pipe sections and touchdown points to minimize damage, using a combination of pressurized fluid and self-propelled modules for propulsion and control, and energy recovery systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the pipeline is laid with standard thickness pipe sections, then the laying cost is reduced, but the pipeline is vulnerable to crushing and rupture under external pressure

Engineering Contradiction:
Improvelaying costVSAvoidresistance to crushing
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The pipeline is divided into segments of standard thickness pipe sections separated by thicker reinforcement sections. The train is correspondingly segmented into multiple cars that can be positioned at different locations along the pipeline, allowing reinforcement at critical points while maintaining standard thickness in non-critical sections.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Thicker pipe sections are placed at specific locations where the pipeline is most vulnerable to crushing, particularly near the touchdown point and at intervals along the S-curve. The train includes both standard cars and reinforcement cars that correspond to these locations, providing localized strengthening where needed while using standard thickness elsewhere.

Inventive Principle:
Principle #3Local quality

2Reliability

If existing plugging techniques are used, then the pipeline is protected from flooding, but they fail to prevent crushing from spreading and endanger pipeline integrity

Engineering Contradiction:
Improveprotection from floodingVSAvoidcrushing damage spread
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The train is divided into multiple cars including a plug car, standard cars, and reinforcement cars. The reinforcement cars with thicker sections are positioned at strategic locations to create physical barriers that prevent crushing from propagating along the pipeline, while the plug car prevents flooding.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Thicker pipe sections are installed in advance at predicted vulnerable locations along the pipeline route. The train is equipped with corresponding reinforcement cars that are positioned ahead of the laying process to provide pre-positioned protection against crushing before it can occur or spread.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Productivity

If the train is continuously propelled forward, then the laying speed is increased, but the train may enter regions of pipeline vulnerable to crushing

Engineering Contradiction:
Improvelaying speedVSAvoidtrain protection
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The train's propulsion is made dynamic and adaptive rather than continuous and uniform. The propulsion system responds to real-time positioning data and pipeline conditions, accelerating when the train is in protected regions and decelerating or stopping when approaching vulnerable areas, allowing high overall speed while maintaining safety.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A control system continuously monitors the train's position relative to the pipeline layout and thicker section locations. This feedback information is used to dynamically adjust propulsion forces, ensuring the train maintains optimal positioning within reinforced sections while maximizing laying speed throughout the overall process.

Inventive Principle:
Principle #23Feedback

4Strength

If thicker pipe sections are distributed along the entire pipeline, then crushing protection is maximized, but the manufacturing cost increases

Engineering Contradiction:
Improvecrushing protectionVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

Instead of using uniformly thick pipeline throughout, the system segments the pipeline into standard thickness sections and strategically placed thicker reinforcement sections. The train is similarly segmented into standard cars and reinforcement cars, allowing cost-effective protection only where structurally necessary.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Thicker pipe sections and reinforcement cars are deployed only at specific locations where the pipeline geometry creates vulnerability to crushing, such as near the touchdown point and at intervals along the S-curve. Standard thickness pipe and cars are used in less vulnerable sections, optimizing the balance between protection and cost.

Inventive Principle:
Principle #3Local quality

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 method effectively prevents pipeline crushing and flooding by strategically positioning the train relative to thicker pipe sections, reducing damage and maintaining pipeline integrity while using low-cost, efficient propulsion and control mechanisms.

Implementation Method 1

the portion of the pipeline between the laying vessel and the bed is subjected to bending stress... the external pressure, particularly in deep water, is much higher than inside the pipeline

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

propelling a train, designed to plug the pipeline, inside the pipeline laid on the bed of the body of water

Methodology Applied
Scientific EffectPressure differential propulsion: Pressure Gradient

Data Source

PatentEP2694855B1Method and system for laying a pipeline on the bed of a body of water
Publication Date: 2015.06.10 SAIPEM SPA
  • EP2694855B1 patent drawingFigure 1
  • EP2694855B1 patent drawingFigure 2
  • EP2694855B1 patent drawingFigure 3~4

AI summary

A method of laying a pipeline (2) on the bed (8) of a body of water (3) includes constructing, on a laying vessel (1), a pipeline (2) having pipe sections of a given thickness, and thicker pipe sections (12) distributed along the pipeline (2); moving the laying vessel (1) forward and laying the pipeline (2) in the body of water (3) as the pipeline (2) is constructed; and propelling a train (13; 32), designed to plug the pipeline (2), in steps inside the pipeline laid on the bed of the body of water; the step travel of the train (13; 32) being related to the position of the thicker pipe sections (12), and to the touchdown point (11) of the pipeline (2) on the bed (8) of the body of water (3).