Subsea Pipeline Connection Tool for Deepwater Rigid Pipe Pull-In
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Solution Overview
Problem
Current methods for connecting rigid subsea pipeline sections are inefficient and costly, particularly in deep water, due to the need for specialized vessels and accurate positioning, which is challenging with rigid pipes.
Innovation Solution
A subsea connection tool and method that involves landing a connection tool on the seabed, locking it to a first pipeline section, connecting a second section via an initiation line, and using a winch and pull-in system to mechanically engage the sections, allowing for accurate alignment and connection without requiring expensive specialized vessels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If specialized pipelaying vessels are used to connect pipeline sections in deep water, then the connection capability is improved, but the installation cost increases significantly
Solution Approach 1:
The patent extracts the connection function from expensive specialized pipelaying vessels and implements it through a standalone subsea connection tool that can be deployed from conventional vessels. The connection tool is landed on the seabed and used to connect pipeline sections directly at the installation site, eliminating the need for costly specialized vessels while maintaining connection capability.
Solution Approach 2:
The patent introduces a subsea connection tool as an intermediary device between the pipeline sections and the installation vessel. This tool serves as a mediator that enables connection operations in deep water without requiring the vessel itself to have specialized connection capabilities, thus reducing vessel cost while maintaining connection reliability.
2Manufacturing precision
If rigid pipeline sections are positioned accurately for connection, then the connection precision is improved, but the positioning difficulty increases due to pipe stiffness
Solution Approach 1:
The patent employs preliminary positioning actions where the connection tool is landed and positioned on the seabed before the pipeline sections are brought into connection position. The tool includes positioning features that guide the pipeline sections into correct alignment, and the initiation line is pre-configured to facilitate controlled positioning during the pull-in operation.
Solution Approach 2:
The patent replaces manual or complex mechanical positioning operations with a winch-based pull-in system that uses controlled tension on the initiation line to draw the pipeline sections together. This mechanical substitution provides precise, controlled positioning that overcomes the stiffness of rigid pipes, enabling accurate connection without difficult manual positioning.
3Ease of manufacture
If pipeline sections are towed from onshore fabrication sites, then the fabrication cost is reduced, but the transportation and installation complexity increases
Solution Approach 1:
The patent divides the pipeline into multiple sections that are fabricated separately at onshore facilities and then towed to the offshore site. The subsea connection tool enables these segmented sections to be connected in situ on the seabed, combining the cost benefits of onshore fabrication with the flexibility of offshore assembly.
Solution Approach 2:
The patent uses the subsea connection tool as an intermediary that facilitates the connection of towed pipeline sections at the offshore installation site. This tool bridges the gap between onshore fabrication and offshore installation, enabling the integration of pipeline sections that have been transported separately without requiring complex integrated fabrication-installation vessels.
Data Source
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AI summary
A method of assembling a pipeline at a seabed location comprises landing a connection tool (10) on the seabed over a free end portion of a first pipeline section (12) already placed on the seabed. The connection tool is locked to the free end portion of the first pipeline section, a lower end of a second pipeline section (26) is connected to the connection tool via an initiation line (68). While applying tension to the initiation line against reaction force of the connection tool, at least a lower end portion of the second pipeline section is landed on the seabed with the lower end facing a free end of the first pipeline section. The lower end of the second pipeline section is then pulled into mechanical engagement with the free end of the first pipeline section.