Spar with improved VIV performance
AssigneeShell Oil Company
InventorsDonald Wayne Allen, Dean Leroy Henning, Stephen W. Balint, David Wayne McMillan
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Abstract
A method for reducing VIV is disclosed for a spar platform having a deck, a cylindrical hull having a buoyant tank assembly, a counterweight and an counterweight spacing structure. The overall aspect ratio of the hull is reduced by providing one or more abrupt changes in hull diameter below the waterline.
Claims10
A method for reducing vortex induced vibrations in a spar platform for developing offshore hydrocarbon reserves. the spar platform having a deck, a cylindrical hull having a buoyant tank assembly, a counterweight and an counterweight spacing structure, the method comprising reducing the aspect ratio of the hull by providing one or more abrupt changes in hull diameter below the waterline.
A spar platform for developing offshore hydrocarbon reserves in deployment at a location subject to at least transitory currents causing a flow there past comprising:
- a deck;
- a buoyant tank assembly, comprising:
- a first cylindrical buoyant section connected to the deck;
- a second cylindrical buoyant section disposed beneath the first buoyant section;
- and
- an abrupt change in relative diameters between the first and second buoyant sections in a manner that will substantially disrupt a correlation in the flow about the buoyant tank assembly so as to mitigate vortex induced vibration effects;
- a counterweight;
- and
- a counterweight spacing structure connecting the counterweight to the buoyant tank assembly.
Dependencies are inferred from the claim text.