Offshore drilling rig and a method of operating the same

Patent metadata

Field	Value
Publication number	US-10323467-B2
Application number	US-201414777325-A
Country	US
Kind code	B2
Filing date	Mar 17, 2014
Priority date	Mar 15, 2013
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

An offshore drilling rig comprising a drill deck, at least one primary well center and a diverter system arranged below the primary well center, a drilling support structure extending upwardly from the drill deck and above the primary well center and the other work center and a first and a second hoisting system supported by the drilling support structure and being adapted for raising or lowering a first and a second load carrier, respectively, and where the offshore drilling rig comprises a positioning system adapted for selectively positioning at least the first load carrier in at least a first or a second horizontal position different from the first horizontal position, where the first load carrier in the first horizontal position is positioned above the primary well center, and in the second horizontal position is positioned above the other work center.

First claim

The invention claimed is:

1. An offshore drilling rig comprising;
a drill deck;
at least two work centers arranged in the drill deck horizontally spaced apart from each other;
a drilling support structure extending upwardly relative to the drill deck;
a first and a second hoisting system supported by the drilling support structure, the first hoisting system being adapted for raising or lowering a first load carrier at a first horizontal position, and the second hoisting system being adapted for raising or lowering a second load carrier at a third horizontal position that is different from the first horizontal position;
at least one top drive suspended from the first load carrier, and where the offshore drilling rig comprises a positioning system adapted for:
positioning the first load carrier selectively in at least the first horizontal position and a second horizontal position that is different from the first horizontal position, so that the drilling rig may raise or lower tubular equipment through a work center at the first and second horizontal positions via the first hoisting system, and
positioning the second load carrier selectively in at least the first and the third horizontal position, so that drilling rig may raise or lower tubular equipment through a work center at the first and third positions via the second hoisting system

wherein the first horizontal position is placed between the second and third horizontal positions and the drilling rig is further arranged to lift tubular equipment suspended from the first and second load carriers through the work center at the first horizontal position using the first and second hoisting systems in cooperation.

2. An offshore drilling rig according to claim 1 wherein the drilling rig is configurable to raise or lower tubular equipment through the work center at the first horizontal position using the first hoisting system and simultaneously raise or lower tubular equipment through a work center at the third horizontal position via said second hoisting system.

3. An offshore drilling rig according to claim 1 wherein the drilling rig is configurable to raise or lower tubular equipment through the work center at the second horizontal position using the first hoisting system without the second hoisting system.

4. An offshore drilling rig according claim 1 wherein the drilling rig is configurable to raise or lower tubular equipment through the work center at the first horizontal position using the second hoisting system without the first hoisting system.

5. An offshore drilling rig according to claim 1 ; wherein the work center at the first horizontal position is either displaceable between at least the first and the third horizontal positions or the drilling rig comprises at least three work centers where at least the work center at the first horizontal position is fixed.

6. An offshore drilling rig according to claim 5 ; wherein the first horizontal position is located between the second and the third horizontal position.

7. An offshore drilling rig according to claim 1 , further comprising a connecting tool having two opposite ends each being adapted for directly or indirectly connecting to one of the load carriers, so that the connecting tool can be carried by the first and second load carriers, and where the connecting tool has an intermediate load carrier arranged between said two opposite ends and being adapted for carrying a load.

8. An offshore drilling rig according to claim 1 , wherein the positioning system is adapted for shifting both said first and second load carriers, being at said first horizontal position or second horizontal positions, to a position next to the first horizontal position, so that the two load carriers are positioned on opposite sides of the first horizontal position to allow both load carriers to operate simultaneously above the first horizontal position.

9. An offshore drilling rig according to claim 1 , wherein the first and the second hoisting system of each of the load carriers lift said load carriers via a lifting cable hanging from a cable crown supported by the drilling support structure, and where the positioning system is adapted for shifting at least one of, or each of the cable crowns to and from the first and the second horizontal position relative to that cable crown where the load carrier is positioned above one of the work centers.

10. An offshore drilling rig according to claim 1 , wherein the hoisting systems comprises at least one substantially vertically extending linear actuator having a stationary end being fixed with respect to the drill deck, and a travelling end comprising at least one cable sheave, wherein the linear actuator is a hydraulic cylinder.

11. An offshore drilling rig according to claim 1 , wherein the positioning system is configured to position the top drive selectively at least the first and the second horizontal positions.

12. An offshore drilling rig according to claim 11 , wherein the position system comprises a retractable dolly for each top drive, the retractable dolly being adapted to connect the top drive to a vertically extending track mounted on the drilling support structure, and to position the top drive selectively in the first and the second horizontal positions above the work centers and being adapted for positioning the top drive at a distance from the track, so that it is vertically aligned above one of the work centers.

13. An offshore drilling rig according to claim 12 , wherein the retractable dolly connecting the top drive to the vertically extending track is adapted so that it only allows the top drive to be vertically aligned above the two of the three horizontal positions being closest to the vertically extending track.

14. An offshore drilling rig according to claim 12 , wherein the positioning system is adapted for positioning each cable crown carrying a load carrier, and where the retractable dolly connecting the top drive suspended from the first load carrier to said vertically extending track are adapted to keep the lifting cable between the cable crown and the load carrier substantially vertical.

15. An offshore drilling rig according to claim 1 , wherein the work center at the first horizontal position is displaceable between at least the first and second horizontal positions.

16. An offshore drilling rig according to claim 1 , wherein one or more work centers are mounted in a substantially horizontal track in the drill deck, and where the drill deck comprises a work center positioning system adapted for selectively moving and positioning each of the work centers in the horizontal track to the first or the second or the third horizontal position in the drill deck.

17. An offshore drilling rig according to claim 16 , wherein the horizontal track is linear at least along a part of it, and where at least one of the work centers is a primary well center with a diverter system arranged below comprising at least one diverter over board tube having a first end being connected to the primary well center and the other end being supported and fixed with respect to the drill deck and having at least one telescopic section between the first and the second end, the telescopic section extending parallel to a linear part of the horizontal track in the drill deck.

18. An offshore drilling rig according to claim 16 , and comprising at least one riser tensioning system arranged below the drill deck, and riser tensioners are mounted on a linear riser tensioner track being arranged below, and in parallel to the horizontal track in the d

Assignees

• Maersk Drilling As

Inventors

• Kannegaard Michael
• Mccoll Allan
• Holck Jesper

Classifications

• E21B15/02 Primary

  specially adapted for underwater drilling (E21B15/04 takes precedence) · CPC title

• E21B19/084

  with flexible drawing means, e.g. cables · CPC title

• E21B19/143

  specially adapted for underwater drilling · CPC title

• E21B7/12

  Underwater drilling (using heave compensators E21B19/09) · CPC title

• E21B19/006

  including heave compensators · CPC title