Offshore drilling rig and a method of operating the same
First Claim
1. An offshore drilling rig comprising:
- a drill deck;
a first work center arranged in the drill deck;
a first hoisting system adapted for raising or lowering tubular equipment through the first work center;
a second work center arranged in the drill deck horizontally spaced apart from the first work center;
a second hoisting system adapted for raising or lowering tubular equipment through at least the second work center;
a riser tensioning system operable to provide tension to said riser;
wherein the offshore drilling rig comprises a first positioning system configured for positioning at least the riser tensioning system selectively at a first horizontal position and a second horizontal position, different from the first horizontal position; and
wherein the first and second work centers are both primary well centers, each comprising a diverter system arranged below the primary well center, each diverter system operatively connectable to a riser extending towards the seafloor, andthe first hoisting system is operable to raise or lower tubular equipment through the said riser at least when said riser tensioning system is positioned at said first horizontal position and the drilling rig is operable to raise or lower tubular equipment through the said riser by means of at least the second hoisting system when the riser tensioning system is positioned at said second horizontal position.
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Accused Products
Abstract
An offshore drilling rig includes a drill deck, at least one work center arranged in the drill deck; a diverter system operatively connectable at least to a riser extending towards the seafloor; a hoisting system adapted for raising or lowering tubular equipment through the work center; wherein the offshore drilling rig includes a first positioning system configured for positioning at least the work center and/or the diverter system and/or a riser tensioning system selectively at a first horizontal position and a second horizontal position, different from the first horizontal position; and wherein the hoisting system is operable to raise or lower tubular equipment through the work center when said work center is positioned at said first horizontal position.
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Citations
21 Claims
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1. An offshore drilling rig comprising:
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a drill deck; a first work center arranged in the drill deck; a first hoisting system adapted for raising or lowering tubular equipment through the first work center; a second work center arranged in the drill deck horizontally spaced apart from the first work center; a second hoisting system adapted for raising or lowering tubular equipment through at least the second work center; a riser tensioning system operable to provide tension to said riser; wherein the offshore drilling rig comprises a first positioning system configured for positioning at least the riser tensioning system selectively at a first horizontal position and a second horizontal position, different from the first horizontal position; and wherein the first and second work centers are both primary well centers, each comprising a diverter system arranged below the primary well center, each diverter system operatively connectable to a riser extending towards the seafloor, and the first hoisting system is operable to raise or lower tubular equipment through the said riser at least when said riser tensioning system is positioned at said first horizontal position and the drilling rig is operable to raise or lower tubular equipment through the said riser by means of at least the second hoisting system when the riser tensioning system is positioned at said second horizontal position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of performing drilling operations by using an offshore drilling rig, the drilling rig comprising:
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a drill deck; a first work center and a second work center arranged in the drill deck horizontally spaced apart from each other, both work centers being operable as a primary well center each comprising a diverter system arranged below the primary well center, each diverter system operatively connectable to a riser extending towards the seafloor, and; a first hoisting system adapted for raising or lowering tubular equipment through at least the first work centers; a second hoisting system adapted for raising or lowering tubular equipment through at least the second work centers; and a riser tensioning system; and wherein the method comprises; positioning the riser tensioning system at a first horizontal position; performing drilling operations through the riser center by means of at least the first hoisting system; moving the riser tensioning system from the first to a second horizontal position, different from the first horizontal position; and continuing drilling operations through the riser work center by means of at least the second hoisting system. - View Dependent Claims (19, 20, 21)
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Specification