DUAL-DERRICK ICE-WORTHY JACK-UP DRILLING UNIT
First Claim
1. A drilling jack-up rig comprising:
- i) a flotation hull having a generally flat upper deck;
ii) an ice-bending portion of said flotation hull extending downwardly from at or near a periphery of said deck and tapering inwardly;
iii) an optional ice deflecting edge extending generally vertically down from a bottom periphery of said ice-bending portion to direct ice around and not under said flotation hull;
iv) at least three legs that are positioned within a perimeter of said flotation hull;
v) a jack-up device associated with each leg to raise and lower each leg; and
vi) at least two derricks mounted on said deck.
2 Assignments
0 Petitions
Accused Products
Abstract
The invention relates to an ice worthy jack-up rig that may extend the drilling season in shallow water off shore Arctic or ice prone locations. The inventive 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 hull is lowered into the water into an ice defensive configuration. The hull is specifically shaped with a lower portion that is an ice-bending surface to bend and break up ice that comes in contact with the hull while in the ice defensive configuration. Furthermore, the ice worthy jack-up rig that comprises at least two derricks so as to double the exploration efficiency and lower the relating costs.
10 Citations
20 Claims
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1. A drilling jack-up rig comprising:
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i) a flotation hull having a generally flat upper deck; ii) an ice-bending portion of said flotation hull extending downwardly from at or near a periphery of said deck and tapering inwardly; iii) an optional ice deflecting edge extending generally vertically down from a bottom periphery of said ice-bending portion to direct ice around and not under said flotation hull; iv) at least three legs that are positioned within a perimeter of said flotation hull; v) a jack-up device associated with each leg to raise and lower each leg; and vi) at least two derricks mounted on said deck. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for drilling in ice prone shallow waters, the method comprising:
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a) providing a jack-up rig having i) a flotation hull having a relatively flat deck at an upper portion thereof and an ice-bending shape along the lower portion thereof where the ice-bending shape extends downwardly and inwardly from the deck, ii) at least three legs that are positioned within a perimeter of the flotation hull, and iii) two derricks mounted on said deck; b) jacking down each leg to engage the sea floor and lift the hull out of the water if ice is not threatening the rig; c) lowering the flotation hull into the water into an ice defensive configuration so that the ice-bending shape extends above and below the sea surface to break or deflect ice that comes against the rig if ice is threatening the rig; and d) drilling from said two derrick during steps b) and/or c). - View Dependent Claims (13, 14)
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- 15. An improved jack-up rig comprising a flotation hull having a flat upper deck and at least three legs that can be lowered through holes in said flotation hull to contact a sea floor, the improvement comprising two derricks on said deck and said flotation hull comprising an ice bending shape that tapers inwardly from said deck so that a bottom of said flotation hull has smaller area than a top of said flotation hull.
Specification