Offshore Pipeline Vibration De-Burial Through Soil Liquefaction
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Solution Overview
Problem
The de-burial of decommissioned pipelines or cables is cumbersome, costly, and time-consuming due to the difficulty in determining their exact position and the need for heavy equipment, making conventional methods inefficient and often leading to them being left buried, which can obstruct new installations or require legislative removal.
Innovation Solution
A vibration device is used to induce transverse vibrations in the pipeline or cable, weakening the surrounding soil through liquefaction, allowing for easier extraction without the need for extensive soil removal, utilizing a vibration unit mounted to the pipeline or cable, or remotely via a support pipe, with optional jetting systems to enhance soil loosening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional digging equipment is used to remove soil covering the buried pipeline or cable, then the pipeline or cable can be removed, but the operation becomes cumbersome, costly, and time-consuming
Solution Approach 1:
The patent applies mechanical vibration through a vibration unit that generates vibrations in the pipeline or cable, which are transmitted to the surrounding soil to reduce its strength and stiffness, enabling easier extraction without extensive digging operations
Solution Approach 2:
The patent changes the physical state of the soil by inducing vibrations that reduce the soil's strength and stiffness parameters, transforming it from a solid state that resists extraction to a weakened state that facilitates pipeline or cable removal
2Ease of operation
If heavy equipment is used for de-burial operations, then the pipeline or cable can be extracted, but the cost and complexity increase significantly
Solution Approach 1:
The pipeline or cable serves itself by acting as the vibration transmission medium, eliminating the need for separate heavy equipment to transmit vibrations to the soil. The existing structure becomes part of the extraction system
Solution Approach 2:
The invention extracts the essential function of heavy equipment (vibration transmission) and implements it through a simplified system where the pipeline or cable itself transmits the vibrations, removing the need for complex external vibration generation equipment
3Difficulty of detecting and measuring
If the exact position of the buried pipeline or cable is unknown, then de-burial becomes more difficult, but conventional methods still require extensive soil removal
Solution Approach 1:
The vibration unit serves multiple functions: it transmits vibrations to weaken the soil, and simultaneously the pipeline or cable acts as both the object to be extracted and the medium for vibration transmission, reducing the need for precise position determination
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 reduces the strength and stiffness of the soil around the pipeline or cable, enabling efficient and cost-effective de-burial by minimizing the need for heavy equipment and time, with the potential for simultaneous jetting to further enhance the de-burial process.
Implementation Method 1
the vibration device comprises at least one vibration unit arranged to induce vibration in a direction transversely to the contact surface... A part of the pipeline or the cable which is buried in, initially undisturbed, intact, soil will start to vibrate
Implementation Method 2
Through this vibration, energy will be induced into the undisturbed or intact soil, causing the strength and/or stiffness of the soil to be reduced, e.g. the soil around the pipeline or the cable may even become liquefied
Data Source
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AI summary
Vibration device for offshore de-burial of a pipeline or a cable, wherein the vibration device has a contact surface for being in contact with a wall of the pipeline or the cable, wherein the vibration device comprises at least one vibration unit arranged to induce vibration in a direction transversely to the contact surface.