Subsea Tethering via Mud Mat and Buried Anchor
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Solution Overview
Problem
Existing systems for tethering subsea structures face challenges in utilizing existing commercial anchors buried under the seafloor, as they interfere with other subsea infrastructures or flowlines, and are difficult to integrate with tensioning systems due to their buried nature.
Innovation Solution
A system comprising an anchor embedded in the seabed, a mud mat partially above the seafloor, and a flexible tension member that extends horizontally and vertically to impart preload, with a tensioning system mounted on either the mud mat or the subsea structure, allowing for efficient tethering of subsea structures using existing anchors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing commercial anchors buried under the seafloor are used for tethering subsea structures, then the need for new anchor deployment is eliminated, but the anchors interfere with other subsea infrastructures or flowlines
Solution Approach 1:
The patent introduces a mud mat as an intermediary component between the buried anchor and the subsea structure. The mud mat serves as a transition element that allows the tensioning system to be mounted on the seafloor while connecting to the buried anchor, thereby enabling tethering without direct interference with subsea infrastructure. The mud mat acts as a mediator that resolves the conflict between utilizing buried anchors and avoiding interference with existing infrastructure.
2Object-affected harmful factors
If mooring anchors are deployed at new locations to avoid interference, then interference with subsea infrastructure is minimized, but the complexity and difficulty of deployment increases
Solution Approach 1:
The patent enables existing buried anchors to serve the dual purpose of both their original function and as tethering anchors for subsea structures. By mounting the tensioning system on the seafloor and connecting it to the buried anchor through the mud mat, the system allows existing infrastructure to serve new purposes without requiring additional deployment operations, thereby reducing deployment complexity while avoiding interference.
3Reliability
If additional mooring anchors are deployed to provide sufficient tethering capacity, then the tethering requirement is met, but the difficulty of deployment and potential interference increases
Solution Approach 1:
The patent makes the buried anchor multi-functional by enabling it to serve both its original mooring function and the new function of tethering subsea structures. The tensioning system mounted on the seafloor connects to the buried anchor through the mud mat, allowing the same anchor to provide both historical mooring capacity and current tethering requirements, thereby meeting reliability needs without additional deployment operations.
Data Source
AI summary
A system for tethering a subsea structure includes an anchor embedded in the sea bed, a mud mat disposed partially above the seafloor, a link attached to the anchor and to the mud mat, and a flexible tension member. One end of the flexible tension member is coupled to a tensioning system configured to pay in and pay out the flexible tension member. The tensioning system is mounted on one of the subsea structure or on the mud mat. The other end of the flexible tension member is coupled to the other of the subsea structure or on the mud mat. The anchor may optionally be buried below the seafloor.