Top-mounted compensator for use in a motion compensation system

Abstract

A bell design crown block for a top mounted compensator includes a removable, tilting sheave block mounted within the outside perimeter of a crown block yoke. An actuator installed in the crown block actuates the tilt function. No hinge adaptor is required and the sheave block does not hang past or below the crown block yoke. When used in a floating platform application, idler sheaves are mounted on the crown block yoke and an optional interface beam may be provided for the active heave cylinder head.

Claims

1. A crown block arranged for use in a top mounted compensator, the crown block [20] comprising: a crown block yoke [21] housing a sheave block [30] having a central rotational axis; and an actuator [50] connected to the sheave block at the central rotational axis of the sheave block and arranged to move the sheave block between an inline position and a tilted position relative to a center line [43] of the crown block.

2. A crown block according to claim 1 further comprising an active heave compensator interface beam located toward a top end [19] of the crown block.

3. A crown block according to claim 1 further comprising the crown block yoke sized to house the sheave block entirely between a top end [29] and a bottom end [27] of the crown block yoke.

4. A crown block according to claim 1 further comprising an axle mount [49] located below and toward a top end of the crown block yoke, the axle mount being complementary in shape to the top end of the sheave block.

5. A crown block according to claim 1 further comprising a pair of interface axles [45] located in an axle mount under a top end of the crown block yoke, wherein the sheave block removably connects to the crown block yoke by the pair of interface axles.

6. A crown block according to claim 1 further comprising a pair of idler sheaves [51] mounted to the crown block yoke at a same level as sheaves [31] of the sheave block.

7. A crown block according to claim 1 further comprising the actuator including an actuator rod [53] connected to the sheave block.

8. A crown block according to claim 1 further comprising the actuator being housed in the crown block.

9. A crown block according to claim 1 further comprising a lubrication manifold [55] in communication with at least the sheave block sheaves.

10. A crown block arranged for use in a top mounted compensator, the crown block [20] comprising: a sheave block [30] having a central rotational axis, said sheave block connected to a crown block yoke [21]; an actuator [50] connected to the sheave block at the central rotational axis of the sheave block and arranged to move the sheave block between a neutral position and a tilted position relative to a center line [43] of the crown block.

11. A crown block according to claim 10 further comprising the crown block yoke housing the sheave block entirely between a top end [29] and a bottom end [27] of the crown block yoke.

12. A crown block according to claim 10 further comprising an active heave compensator interface beam located toward a top end [19] of the crown block.

13. A crown block according to claim 10 further comprising an axle mount [49] located below and toward a top end of the crown block yoke, the axle mount being complementary in shape to the top end of the sheave block, a hinge [47] being formed between the complementary shapes.

14. A crown block according to claim 10 further comprising a pair of interface axles [45] located in an axle mount under a top end of the crown block yoke, wherein the sheave block removably connects to the crown block yoke by the pair of interface axles.

15. A crown block according to claim 10 further comprising a pair of idler sheaves [51] mounted to the crown block yoke at a same level as sheaves [31] of the sheave block.

16. A crown block according to claim 10 further comprising the actuator including an actuator rod [53] connected to the sheave block.

17. A crown block according to claim 10 further comprising the actuator being housed in the crown block.

18. A crown block according to claim 10 further comprising a lubrication manifold [55] in communication with at least the shear block sheaves.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an example of a top mounted compensator assembly in which preferred embodiments of the crown block may be a part. The crown block shown here is a prior art crown block.

(2) FIG. 2 is an isometric view of a preferred embodiment of the crown block. The crown block includes a removable, tilting sheave block located within the crown block yoke.

(3) FIG. 3 is a side elevation view of a preferred embodiment of the crown block.

(4) FIG. 4A is a section view of the crown block taken along section line 4A-4A of FIG. 3 showing the sheave block in an inline position.

(5) FIG. 4B is section view of with the sheave block tilted at an angle a by an actuator.

(6) FIG. 5 is a section view taken along section line 5-5 of FIG. 3.

(7) FIG. 6 shows an example of the crown block when landed on the water table with the sheave block tilted. Other portions of the top mounted compensator assembly shown in FIG. 1, as well as the lower end of the derrick and the drill floor, are not shown in this view.

ELEMENTS AND NUMBERING USED IN THE DRAWINGS AND DETAILED DESCRIPTION

(8) 10 Motion compensation system 11 Active heave compensator 13 Drawworks (usually located at drillfloor) 15 Cable 17 Top drive 19 Top end or plane of 20 20 Crown block (with bell design) 21 Crown block yoke 25 Pad eyes 27 Bottom end or plane of 21 29 Top end or plane of 21 30 Sheave block 31 Sheaves 33 Central (rotational) axis of 30 35 Pad eyes 37 Bottom end 39 Top end 41 Interface beam 43 Centerline (running perpendicular to the central rotational axis of the sheave block) 45 Interface axle 47 Hinge or hinge joint 49 Axle mount 50 Actuator (arranged at or about the central rotational axis of the sheave block) 51 Idler sheaves 53 Actuator rod 55 Lubrication manifold 57 Guide rail rollers 60 Stabilizing (rocker arms and sheaves) assembly 80 Traveling block Tilt angle

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(9) Referring now to FIG. 1, a motion compensation system 10 is shown in which preferred embodiments of a crown block 20 may be a part (see FIGS. 2-6). In one embodiment, the motion compensation system 10 includes a top-mounted crown block 20 that has a bell design, a traveling block 80, and an optional stabilizing assembly 60 made of rocker arms and wire sheaves located between the two blocks 20, 80. A cable 15with one end connected to the drawworks 13 and the other end connected to the floating vessel as a deadlinepasses through the crown block 20 and the optional stabilizing assembly 60

(10) The cable 15, along with the stabilizing assembly 60, is used to control the movement of the crown block 20 relative to the traveling block 80. When used in fixed platform applications, stabilizing assembly 60 is not needed. In floating platform applications, stabilizing assembly 60 helps improve performance.

(11) The traveling block 80 may be connected to a top drive 17 that helps move the traveling block 80 and imparts a load on the drill string. The crown block 20 may be coupled to compensator cylinders in a manner similar to that described in US 2015/0008382 A1 to Bergan (herein incorporated by reference).

(12) Referring now to FIGS. 2-6, a preferred embodiment of the crown block 20 includes pad eyes 25 and a crown block yoke 21 that houses a tilting sheave block 30. Sheave block 30 removably connects to the crown block yoke 21 by two interface axles 45 and includes pad eyes 35. The interface axles 45 are located toward (and under) a top end 29 of the crown block yoke 21.

(13) An actuator 50 is installed in the crown block 20 to actuate the tilt function of the sheave block 30. Actuator 50 includes electromechanical, hydraulic or pneumatic controls and related circuitry of a kind known in the art to create the desired amount of actuation (and resulting tilt angle ). Where active heave compensation is used, crown block 20 may include an interface beam 41 in communication with an active heave compensator 11.

(14) Actuator 50, which includes a rod 53 connected to the sheave block 30, is arranged at or about a central rotational axis 33 of the sheave block 30 to move the sheave block 30 between an inline position and a tilted position relative to a center line 43 of the crown block 20. When actuator 50 is in its neutral position, the sheave block 30 is in the inline position. When actuator 50 is in a retracted (pull) position relative to neutral, sheave block 30 is in the titled position.

(15) The degree of tilt relative to a centerline 43 of the crown block 20 is determined by application requirements. Regardless of the degree of tilt, the tilt is such that it reduces the fleet angle, thereby extending the drill wire's operating life.

(16) The sheave block 30 is housed withinand does not hang past or belowthe crown block yoke 21. The bottom end 37 of the sheave block 30 is located just above the bottom end 27 of the crown block yoke 21 and the top end 39 of the sheave block 30 is located under the top end 19 of the crown block 20. The top end 39, which is complementary in shape to the axle mount 49, acts as a hinge or hinge joint 47.

(17) Two idler sheaves 51 are mounted on the crown block yoke 21 at the same level as the sheave block sheaves 31. This prevents collision between the drill wire and the tilting sheave block 30. When used in a fixed platform application, the idler sheaves 51 may be mounted to the crown block yoke 21 or to the platform.

(18) A lubrication manifold 55 is provided for shear block sheaves 31 and idler sheaves 51 bearing lubrication and for guide rail roller 57 bearing lubrication. The manifold 55 can be accessed from a platform (not shown) that is spaced apart from the crown block 20. Where lubrication-free bearings are used, the manifold 55 can be removed.

(19) The preferred embodiments provide examples of the invention. The invention itself is defined by the following claims, including elements equivalent to those recited in the claims.