Ice worthy jack-up drilling unit with gas agitated ice prevention

摘要

An ice worthy jack-up rig that may extend the drilling season in shallow water off shore Arctic or ice prone locations. The rig would work like a conventional jack-up rig while in open water with the hull jacked up out of the water. However, in the event of ice conditions, the legs are held in place by cans embedded in the sea floor to resist lateral movement of the rig and the hull is lowered into the water into an ice defensive configuration. The hull is specifically shaped with an ice-bending surface to bend and break up ice that comes in contact with the hull while in the ice defensive configuration.

主权项

1. An ice worthy jack up rig for drilling for hydrocarbons in potential ice conditions in offshore areas comprising:
a flotation hull having a relatively flat deck at the upper portion thereof and an ice bending shape along the lower portion thereof and extending downwardly and inwardly around the periphery of the hull where the ice bending shape extends from an area of the hull near the level of the deck and extends downwardly near the bottom of the hull; an ice deflecting portion extending around the perimeter of the bottom of the hull to direct ice around the hull and not under the hull; at least three legs that are positioned within the perimeter of the bottom of the flotation hull wherein the legs are arranged to be lifted up off the seafloor so that the rig may be towed through shallow water and also extend to the sea floor and extend further to lift the hull partially or fully out of the water; a jack up device associated with each leg to both lift the leg from the sea bottom so that the ice worthy jack up rig may float by the buoyancy of the hull and push the legs down to the seafloor and push the hull partially up and out of the water when ice floes threaten the rig and fully out of the water when ice is not present; and a gas agitation system including holes in seafloor engaging spud cans at bottom ends of the legs for releasing bubbles through the holes to agitate the water near the legs and reduce issues with ice near the legs and prevents ice from forming on the legs.