Seafloor Pipeline Sectioning and Lift Removal After Trenching
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Solution Overview
Problem
Current methods for removing larger pipelines from the seafloor are impractical due to strain on the pipe sections between the barge and the seafloor, leading to potential breakage and safety issues, while traditional solutions focus on cleaning rather than removal, which is now required by regulations.
Innovation Solution
A system comprising a barge, a subsea trenching device, a hydraulic subsea shear, and a grapple, controlled by respective controllers, which uses pressurized water and air to excavate and cut the pipeline, allowing for one-pass removal and lifting of cut pipe sections onto a recovery barge, reducing the need for additional equipment and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional methods are used to lift larger pipelines onto a barge, then the pipeline can be removed from the seafloor, but the strain on the pipe sections between the barge and the seafloor causes breakage and safety issues
Solution Approach 1:
The pipeline is divided into smaller sections by cutting it into manageable segments. Each segment is then individually lifted and placed on the barge, eliminating the need to lift the entire pipeline at once and reducing the strain on any single pipe section.
Solution Approach 2:
The pipeline is first uncovered from the seafloor using a trenching device before cutting and lifting operations begin. This preliminary action of exposing the pipeline allows for controlled cutting and segment-by-segment removal, preventing the need to lift the entire buried pipeline at once.
2Adaptability or versatility
If traditional methods are used to remove pipelines, then smaller pipelines can be removed, but larger pipelines cannot be removed due to strain limitations
Solution Approach 1:
The pipeline removal process is segmented into distinct operations: uncovering, cutting into sections, and incremental lifting. This segmentation allows the same system to handle pipelines of various sizes by adjusting the number and length of segments, making the method adaptable to both small and large pipelines.
Solution Approach 2:
The system uses dynamic, adjustable components including hydraulic shears for cutting at different positions, adjustable buoyancy devices for controlling lift forces, and modular trenching equipment. These dynamic elements allow the system to adapt its operation to pipelines of different sizes and conditions.
3Reliability
If multiple boats and barges are used for pipeline removal, then the pipeline can be removed, but the process becomes less efficient and requires additional equipment
Solution Approach 1:
Multiple functions that traditionally required separate vessels are merged into a single integrated system. The barge carries both the trenching device for uncovering the pipeline and the hydraulic shear for cutting, eliminating the need for separate boats for each operation and reducing overall equipment complexity.
Solution Approach 2:
The barge is designed as a multi-functional platform that performs trenching, cutting, and lifting operations. This universal equipment can handle the entire pipeline removal process alone, making additional specialized vessels unnecessary and simplifying the overall operation.
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
Enables the safe and efficient removal of larger pipelines from the seafloor by excavating, cutting, and lifting them in a single operation, reducing strain on the pipe and minimizing the need for additional vessels, thus addressing the impracticality of traditional methods and complying with new regulatory requirements.
Implementation Method 1
said trenching device controller is capable of delivering pressurized water to said subsea trenching device by a pressurized water hose, and said subsea trenching device is configured to spray said pressurized water out of said plurality of nozzles, thereby excavating a trench around a length of pipe buried below a seafloor
Implementation Method 2
each of said plurality of air lift columns is configured to accept said pressurized air through each respective said air inlet, further wherein each of said plurality of air lift columns is capable of lifting water and particulate matter from a seafloor into each respective said opening, through each respective said interior space, and out of each respective said outlet as a result of said pressurized air flowing through each respective said interior space
Data Source
AI summary
The present invention relates to a system and method for uncovering and removing pipeline from the seafloor using a subsea trenching system using pressurized water to uncover pipe, a subsea shear carried by a barge to cut lengths of the pipeline, and a grapple carried by a barge to lift cut lengths of pipeline for placement on a pipe haul and recovery barge.