Subsea Cable Bundle Pull-Through for Integrated DCFO Installation
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Solution Overview
Problem
The use of direct current and fibre optic (DCFO) cables in subsea installations is hindered by increased costs and installation times due to the need for separate laying and trenching of these cables to subsea structures.
Innovation Solution
A method and system for installing a subsea cable bundle where the DCFO cable is attached to the outside of an umbilical, allowing it to be pulled through a J-tube and laid together with the umbilical, with the DCFO cable being detached and connected to the subsea structure at a target location, eliminating the need for separate trenching and splitting operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DCFO cable is installed separately from umbilical, then DCFO cable can provide power and signals to subsea structure, but installation costs and time increase due to separate laying and trenching operations
Solution Approach 1:
The patent combines the DCFO cable and umbilical into a single cable bundle for simultaneous laying operations. The DCFO cable is attached to the outside of the umbilical at defined locations, allowing both components to be installed together in one operation rather than separately, thereby reducing installation time and costs while maintaining the ability to provide power and signals to the subsea structure
2Device complexity
If DCFO cable is attached to outside of umbilical, then installation complexity is reduced, but cable bundle handling and pulling operations become more complex
Solution Approach 1:
The cable bundle is designed with segmented attachment points where the DCFO cable is attached to the umbilical at specific locations rather than along its entire length. This segmentation allows for easier handling and pulling operations while maintaining the integrated installation approach, as the attachment points can be strategically positioned to facilitate operations
Solution Approach 2:
The patent introduces a pulling head as an intermediary device that facilitates the pulling of the cable bundle through the J-tube. The pulling head is connected to the cable bundle and allows for controlled retrieval and positioning, simplifying the handling of the combined DCFO cable and umbilical assembly during installation operations
3Ease of manufacture
If DCFO cable is integrated inside umbilical, then manufacturing is simplified, but manufacturing constraints prevent sufficiently long cables from being integrated
Solution Approach 1:
The patent employs a nested configuration where the DCFO cable is attached to the outside of the umbilical at specific sections rather than being fully integrated inside. This allows the DCFO cable to extend beyond the umbilical length constraints while maintaining a compact, organized arrangement that simplifies manufacturing compared to completely separate installation
4Reliability
If separate trenching is performed for DCFO cable, then cable protection is improved, but installation costs and time increase
Solution Approach 1:
The patent combines the laying and trenching operations into a single integrated process. The cable bundle containing both the umbilical and DCFO cable is laid together in one operation, eliminating the need for separate trenching of the DCFO cable. This maintains adequate cable protection while significantly improving installation efficiency and reducing costs
Data Source
AI summary
A method of installing a subsea cable bundle including an umbilical and at least one direct current and fibre optic (DCFO) cable attached to an outside of the umbilical includes connecting a first end of the cable bundle to a pulling head, lowering the first end of the cable bundle into the se, connecting the pulling head to a winch cable of a winch (the winch may be connected before or after lowering the first end), the winch being located on a platform and the winch cable extending from the platform into the sea through a J-tube, and using the winch to pull the first end of the cable bundle up to the platform through the J-tube. The method further includes laying the cable bundle on the seafloor, and at a target location, at or close to a subsea structure, detaching the DFCO cable from the umbilical and connecting the DCFO cable and the umbilical at their second ends to the subsea structure.