GB2549176A

GB2549176A - Top drive for a drilling rig

Info

Publication number: GB2549176A
Application number: GB1702355.7A
Authority: GB
Inventors: Lanz Stian
Original assignee: Mhwirth AS
Current assignee: Mhwirth AS
Priority date: 2016-03-02
Filing date: 2017-02-14
Publication date: 2017-10-11
Anticipated expiration: 2037-02-14
Also published as: GB2549176B; GB201702355D0; NO345334B1; NO20160361A1

Abstract

A top drive (100, Fig. 1) for a drilling rig having a longitudinal axis 16, a top drive housing 1, a pivotable coupling 6c&d, first and second, preferably telescopic, suspension elements 6a&b and a back-up wrench (BUW) 7. BUW 7 is suspended from housing 1 via suspension elements 6a&b and pivotable coupling 6c&d. There is a releasable coupling 18a&b between first suspension element 6b and BUW 7, allowing BUW 7 to be fully disconnected from first suspension element 6b. Pivotable coupling 6c&d, preferably provided at a connection point 6d between BUW 7 and second suspension element 6a, allows pivoting of the entire BUW 7 when BUW 7 is disconnected from first suspension element 6b. Pivoting occurs in a plane substantially perpendicular to central longitudinal axis 16 and preferably around a central axis of second suspension element 6a that is parallel to central longitudinal axis 16. A stack 17 is preferably provided having an inside blow out preventer (IBOP) 10&11 and a main drive shaft (4, Fig. 1). Stack 17 may be carried by main drive shaft (4, Fig. 1) or BUW 7 where it is preferably spaced from central longitudinal axis 16.

Description

TOP DRIVE FOR A DRILLING RIG The present invention relates to a top drive for a drilling rig.

BACKGROUND

In the oil and gas industry, top drives are commonly used for rotating drill pipe during drilling operations. The top drive is generally arranged in a drilling rig, and raised and lowered using a hoisting system, such as a drawworks arrangement. The top drive comprises motors, e.g., electric or hydraulic motors, to provide rotational torque on the drill string.

Top drives are subject to high operational demands. In use, the top drive is usually subjected to very high forces due to the high torques required during drilling and large weight of the drill string. The top drive will also see large load variations during the repeated connect/disconnect sequences when adding or removing sections of pipe to the drill string, and it may also be subject to very high adverse loads such as vibrations or other forces extending upwards through the drill string, for example during jarring events. Top drives therefore require periodic inspection and maintenance.

Related prior art, useful to understand the design and use of conventional top drive systems, include the following patent publications: US 2008/135228 A1; US 2006/113084 A1; US 5,388,651 A; EP 0747567 A2; EP 0712992 A2; US 2007/074874 A1; US 2008/099221 A1; US 2008/238095 A1; US 2006/113087 A1; US 3,768,579 A; US 4667752 A; US 7,055,594 B1; US 5433279 A; US 6276450 B1; US 2005/269104 A1; US 2005/173154 A1; US 4753300 A; and US 4878546 A. A continuous need exists for improved systems and methods in relation to top drive operation and maintenance, in particular in light of the tendency of the industry to move into harsher and more challenging areas (e.g., deepwater resources or arctic areas). This includes solutions for improving reliability and for simplifying maintenance of the top drive and its various components.

SUMMARY

The object of the present invention is to provide an improved method and system for operating and/or carrying out maintenance and repairs on top drives, obviating or reducing disadvantages associated with known systems and techniques.

In an embodiment, there is provided a top drive for a drilling rig, the top drive having a central longitudinal axis and comprising: a top drive housing; a pivotable coupling; a first suspension element; a second suspension element; a back-up wrench, the back-up wrench being suspended from the top drive housing via the first suspension element, the second suspension element, and the pivotable coupling; and a releasable coupling arranged between the first suspension element and the back-up wrench whereby the back-up wrench can be fully disconnected from the first suspension element, wherein the pivotable coupling is configured to allow a pivoting of the entire back-up wrench in a plane which is substantially perpendicular to the central longitudinal axis when the back-up wrench is disconnected from the first suspension element.

In an embodiment, the pivotable coupling is provided in the second suspension element.

In an embodiment, the top drive further comprises a connection point arranged between the second suspension element and the back-up wrench and the pivotable coupling is provided in the connection point.

In an embodiment, the first suspension element and/or the second suspension element are telescopic cylinders.

In an embodiment, the back-up wrench is pivotable around an axis which is parallel to the central longitudinal axis.

In an embodiment, the back-up wrench is pivotable around a central axis of the second suspension element.

In an embodiment, the top drive further comprises a stack comprising at least one inside blow out preventer and a main drive shaft wherein the top drive has: (i) a first operational configuration in which the stack is carried by the main drive shaft of the top drive, and (ii) a second operational configuration in which the stack is carried by the back-up wrench.

In an embodiment, the stack is spaced from the central longitudinal axis of the top drive in the second operational configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described in greater detail below on the basis of embodiments and of the drawings in which:

Fig. 1 illustrates a top drive;

Fig. 2 illustrates a back-up wrench;

Fig. 3 illustrates the back-up wrench of Fig. 2 in a first operating position;

Fig. 4 illustrates the back-up wrench of Fig. 2 in a second operating position; and

Fig. 5 illustrates the back-up wrench of Fig. 2 in a third operating position. DETAILED DESCRIPTION

Exemplary embodiments of the present invention will now be described with reference to the figures. The basic design and functionality of conventional top drive systems have previously been described and will therefore not be described in detail herein. Reference is made to the above mentioned patent publications.

Fig. 1 shows a top drive 100, having a housing 1, drilling motors 2a and 2b, and a gear box 3. The drilling motors 2a and 2b drive a main drive shaft 4 via the gear box 3. A telescopic torque arrestor frame 5 is connected to the housing 1 and comprises a first cylinder 6a, a second cylinder 6b, and a back-up wrench (BUW) 7. The back-up wrench can be moved vertically in relation to the frame 1 via the first and second cylinder 6a/6b. Fig. 1 further shows an upper inside-blow-out-preventer (IBOP) 10, a lower IBOP 11, and a saver sub 12, all threadedly connected and fixed to the drive shaft 4 of the top drive. Elevator links 13 are provided to handle sections of drill pipe by means of an elevator (not shown).

The BUW 7 has a central passage through its body and on each side of the passage a jaw 8 with a die 9 (see Fig. 2). Hydraulic cylinders (not shown) are provided inside the BUW 7 to drive the jaws towards a drill pipe (not shown). When connecting or disconnecting a section of drill pipe to the top drive, the jaws in the BUW 7 will clamp the drill pipe, whereby the threaded connection between the saver sub 12 and the drill pipe can be made up or broken out by applying the required torque with drilling motors 2a and 2b. The torque for holding the drill pipe will thus be taken up by the torque arrestor frame 5 and transmitted to the housing 1 so that a high-torque connection can be made.

The BUW 7 is further provided with toothed surfaces 14a and 14b (see Fig. 2). The toothed surfaces 14a and 14b are provided on movable plates 15a and 15b, which are slidable within the body of the BUW 7. The toothed surfaces may, however, also be provided directly in the body of the BUW 7. The toothed surfaces comprise a plurality of teeth projecting inwardly in relation to a longitudinal axis 16 (see Fig. 1) of the top drive. The teeth may alternatively project upwards towards the housing 1 as seen from the BUW 7.

The movable plates 15a and 15b have a retracted position in which the plates are spaced from the central passage, as can be seen in Fig. 2, and an advanced position in which the plates are positioned towards the central passage, as can be seen in Figs 3 and 4.

The toothed surfaces 14a and 14b are adapted to cooperate with a corresponding grooved surface on a threaded element, such as a kelly valve, an IBOP, or a saver sub. By bringing the toothed surfaces into engagement with a grooved surface on the threaded element, the toothed surface may take up and transfer any torque applied to the threaded element by the drilling motors 2a and 2b to the torque arrestor frame 5.

Figs. 3 and 4 show a process of breaking out internal subs according to the present invention. As in Fig. 1, an upper IBOP 10, a lower IBOP 11, and a saver sub 12 (hereinafter likewise referred to as “subs”) are suspended by the top drive. In Fig. 3, the movable plates 15a and 15b have been brought to the advanced position, i.e., brought together horizontally towards the central passage. The upper IBOP 10, lower IBOP 11 and saver sub 12 are all provided with grooves 10a, 11a and 12a, respectively, on their outer circumference.

In Fig. 4, the BUW 7 has been raised by the first cylinder 6a and the second cylinder 6b to bring the toothed surfaces 14a and 14b into engagement with the grooves 12a of the saver sub. This forms a rotational lock so that the saver sub 12 can now be broken out, i.e., its threaded connection to the lower IBOP 11 can be released by applying torque with the drilling motors 2a and 2b. The same procedure can be used to break out the other subs, either individually, or the whole IBOP stack.

According to this embodiment of the present invention, there is therefore no need to clamp the subs with the jaw 8 and die 9 for breaking out or making up the IBOP stack. This reduces the risk of damage to the subs and allows higher torques to be applied in the threaded connections between the individual subs and with the drive shaft 4.

In this embodiment of the present invention, the grooved surface on the upper IBOP 10 and the lower IBOP 11 are provided in a lower part of those subs.

This provides the advantage that the BUW 7 only needs to be raised sufficiently high to reach the grooved surfaces, and not, for example, to the midpoint or upper part of the IBOP 10 or IBOP 11. This allows for a more compact design, e.g. a reduced total height, of the torque arrestor frame.

Fig. 5 shows a top drive according to a further embodiment of the present invention. As can be seen from Fig. 5, the BUW 7 is suspended from a top drive housing 1 by a first suspension element 6b and a second suspension element 6a. The first and second suspension elements 6a and 6b are telescopic cylinders. They may, however, also be other elements suitable for suspending the BUW 7. A releasable coupling having a first part 18a and a second part 18b allows the first suspension element 6b to be selectively connected or disconnected from the BUW 7. The coupling may be bolts and nuts, as illustrated in Fig. 5, or any other suitable type of mechanical coupling.

The top drive further comprises a pivotable coupling adapted to allow for a pivoting of the entire BUW 7 substantially in the horizontal plane when the BUW 7 is disconnected from the first suspension element 6b. The pivotable coupling may be provided in a connection 6c between a first part 6e and a second part 6f of the second suspension element 6a. As shown in Fig. 5, the second suspension element 6a can, for example, be a telescopic cylinder wherein the first part 6e is a cylinder housing and the second part 6f is a rod. The rod can be made rotatable in relation to the housing in a manner known in the art. The pivotable coupling may alternatively be provided in a connection 6d between the BUW 7 and the second suspension element 6a. This may be achieved, for example, via a bearing arrangement in the BUW 7.

The BUW 7 may thus be pivoted, or swung out, in relation to its regular operating position. Easier access to an IBOP stack 17 can be achieved in the swung out position. This is achieved by disconnecting the IBOP stack 17 from the main drive shaft 4 (see Fig. 1), clamping the IBOP stack 17 with a jaw 8 or with movable plates 15a and 15b (see Fig. 2), and swinging out the BUW 7.

The IBOP stack 17 is thus supported by the BUW 7 and spaced from its regular operating position in line with a central longitudinal axis 16 of the top drive.

After swinging out the BUW 7, the IBOP stack 17 can more easily be accessed and removed, for example with a lifting sling, and a new sub or IBOP stack can be inserted into the BUW 7.

In the embodiment shown in Fig. 5, the entire BUW 7 is swung out, thus providing support for the IBOP stack 17 at all times until substantially the full weight of the IBOP stack 17 has been taken by, for example, a crane via a lifting sling. Swinging out the IBOP stack 17 may permit a crane or the like to lift the IBOP stack 17 vertically out of the BUW 7. This eases handling and improves safety.

The terms toothed and grooved as used herein shall be taken to mean any type of teeth, grooves, serrations, splines or the like, suitable for creating an interlocking engagement between two elements in which the elements are locked for relative motion in at least one direction or direction of rotation.

Claims

1. A top drive (100) for a drilling rig, the top drive (100) having a central longitudinal axis (16) and comprising: a top drive housing (1); a pivotable coupling; a first suspension element (6b); a second suspension element (6a); a back-up wrench (7), the back-up wrench (7) being suspended from the top drive housing (1) via the first suspension element (6b), the second suspension element (6a), and the pivotable coupling; and a releasable coupling (18a, 18b) arranged between the first suspension element (6b) and the back-up wrench (7) whereby the backup wrench (7) can be fully disconnected from the first suspension element (6b), wherein the pivotable coupling is configured to allow a pivoting of the entire back-up wrench (7) in a plane which is substantially perpendicular to the central longitudinal axis (16) when the back-up wrench (7) is disconnected from the first suspension element (6b).

2. The top drive (100) as recited in claim 1, wherein the pivotable coupling is provided in the second suspension element (6a).

3. The top drive (100) as recited in claim 1, further comprising: a connection point (6d) arranged between the second suspension element (6a) and the back-up wrench (7), wherein the pivotable coupling is provided in the connection point (6d).

4. The top drive (100) as recited in any of claims 1 to 3, wherein the first suspension element (6b) and/or the second suspension element (6a) are telescopic cylinders.

5. The top drive (100) as recited in any of claims 1 to 4, wherein the backup wrench (7) is pivotable around an axis which is parallel to the central longitudinal axis (16).

6. The top drive (100) as recited in claim 5, wherein the back-up wrench (7) is pivotable around a central axis of the second suspension element (6a).

7. The top drive (100) as recited in any of claims 1 to 6, further comprising: a stack (17) comprising at least one inside blow out preventer (10,11); and a main drive shaft (4) wherein the top drive (100) has (i) a first operational configuration in which the stack (17) is carried by the main drive shaft (4) of the top drive (100), and (ii) a second operational configuration in which the stack (17) is carried by the back-up wrench (7).

8. The top drive (100) as recited in claim 7, wherein the stack (17) is spaced from the central longitudinal axis (16) of the top drive (100) in the second operational configuration.