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Subsea Buoy to Track Large Ice Features

IP.com Disclosure Number: IPCOM000240212D
Publication Date: 2015-Jan-13
Document File: 2 page(s) / 111K

Publishing Venue

The IP.com Prior Art Database

Abstract

Marine oil exploration, development, and production in the high Arctic will require active management to protect floating structures from large ice features, e.g., multi-year ice and first year sails / keels. This management may require identifying these features many tens of kilometers from the structure requiring protection. Many remote detection methods using airborne systems and various forms of electromagnetic radiation have been evaluated. The challenge of active management, however, may require use of multiple detection platforms to ensure continuous operation under all conditions. The envisioned concept is a method of tracking large ice features using a system that is positioned entirely below the ice. This will allow the system to be located in an environment that has relatively constant conditions. The concept is to use a system of underwater buoys that are positioned before the ice season in an optimal configuration around a floating structure that requires protection from large ice features.

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Subsea Buoy to Track Large Ice Features

Marine oil exploration, development, and production in the high Arctic will require active management to protect floating structures from large ice features, e.g., multi-year ice and first year sails / keels. This management may require identifying these features many tens of kilometers from the structure requiring protection. Many remote detection methods using airborne systems and various forms of electromagnetic radiation have been evaluated. The challenge of active management, however, may require use of multiple detection platforms to ensure continuous operation under all conditions. The envisioned concept is a method of tracking large ice features using a system that is positioned entirely below the ice. This will allow the system to be located in an environment that has relatively constant conditions.

Concept Description

The concept is to use a system of underwater buoys that are positioned before the ice season in an optimal configuration around a floating structure that requires protection from large ice features. The buoys will consist of an anchor that is positioned on the seabed, a tether that connects the buoy to the anchor, and a buoy. The tether will be long enough to allow the buoy to float at a position that ensures the buoy will be impacted by the bottom of the floating ice as it passes. The buoy flotation could be set to give the buoy a density that automatically keeps it positioned at the appropriate water depth during changes in sea level due tides.

The buoy will be equipped with sensors that allow it to sense the motion that it experiences as it impacts the rough underside of the ice. These sensors could include pressure sensors and inertial sensors - solid-state gyroscopes / accelerometers. This motion will likely have characteristics that allow it to be distinguished from motion that the buoy experiences due to currents.

If necessary, the pressure sensors on the buoy will be used to maintain the buoys at a desired depth. This system may be necessary if the buoys are pushed too deep into the water because of currents. If this happens, the pressure sensor will send a signal that causes the tether to lengthen using an appropriate lengthening / retracting system located in the buoy or in the anchor. Other methods are possible.

Each buoy can be powered by either individual batteries or by subsea electrical lines that transfer power from a central location. The batteries could be located within the anchor system of the buoy or within the buoy itself. Ideally, the batteries will have a life that allows the buoy to operate the entirety of the ice season. Then during the o...