BACKGROUND OF THE DISCLOSURE

Field of the Disclosure

[0001] The present disclosure generally relates to a compensated top drive unit and elevator links.

Description of the Related Art

[0002] In the construction and completion of oil and gas wells, a drilling rig is used to facilitate the insertion and removal of tubular strings into a wellbore. Tubular strings are constructed by inserting a first tubular into a wellbore until only the upper end of the tubular extends out of the wellbore. A gripping member close to the surface of the wellbore then grips the upper end of the first tubular. The upper end of the first tubular has a threaded box end for connecting to a threaded pin end of a second tubular. The second tubular is lifted over the wellbore center, lowered onto or "stabbed into" the upper end of the first tubular, and then rotated such that the pin end of the second tubular is threadedly connected to the box end of the first tubular.

[0003] This process may be repeated to form a tubular string of desired length. However, it is desired not to damage the threads when the pin end is stabbed into the box end, or when torque is applied to overcome the weight of the second tubular resting on the threads. It is also desired that the drilling rig operator lowers the second tubular at the same rate at which the threads draw together. This reduces the chances of damaging the threads of the tubular and/or tubular string during makeup. Damaging the threads may result in improper connection between the tubular and the tubular string and leaks in the tubular string.

[0004] Therefore, there is a need for new and improved methods and apparatus for making up tubular connections.

SUMMARY OF THE INVENTION

[0005] Embodiments of the invention relate to apparatus and methods of making up a tubular with a tubular string. In one embodiment, a top drive unit includes a top drive housing, a drive stem disposed in the top drive housing, a carrier configured to axially move the drive stem relative to the top drive housing, and a drive mechanism for rotating the drive stem.

[0006] A method of making up a tubular connection using a top drive unit includes connecting a makeup tool to a drive stem of the top drive unit, engaging a tubular using the makeup tool, supporting the tubular using a carrier, rotating the tubular using the drive stem to connect the tubular to a tubular string, and moving the drive stem and the carrier axially relative to the top drive unit during connection of the tubular to the tubular string.

[0007] A method of making up a tubular connection using a top drive unit includes connecting an elevator to a bail housing of the top drive unit, engaging a tubular using a tong assembly, supporting the tubular using a carrier, rotating the tubular using the tong assembly to connect the tubular to a tubular string, and moving the carrier and the bail housing axially relative to the top drive unit during connection of the tubular to the tubular string.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

[0009] Figure 1 illustrates a top drive unit in a lower, extended position according to one embodiment.

[0010] Figure 2A illustrates a top drive unit in an upper, retracted position according to one embodiment.

[0011] Figure 2B illustrates an enlarged view of the top drive housing and bail housing of the top drive unit. [0012] Figure 3 illustrates a perspective view of the top drive unit connected to a makeup tool during makeup of a tubular with a tubular string.

[0013] Figure 4 illustrates a perspective view of the top drive unit connected to an elevator for gripping and lifting a tubular.

DETAILED DESCRIPTION

[0014] Figure 1 is a schematic view of a top drive unit 100 in a lower, extended position. The top drive unit 100 is configured to compensate for axial movement of a tubular during makeup or breakout of a tubular with a tubular string. The top drive unit 100 may connected to a hoist bail 105. The hoist bail 105 may be disposed at the top of the top drive unit 100 and have an arched portion for connecting to a hook of a drawworks. The hook may be connected to the drawworks by a drilling line for lifting and lowering the top drive unit 100.

[0015] Referring to Figures 1 and 2A-B, the top drive unit 100 may include a top drive housing 120, a drive mechanism 120d, a thrust bearing 122 (Fig. 2B), a drive stem 123, a carrier 125, and compensation cylinders 126 (Fig. 2B). The top drive housing 120 may be a cylinder with a bore 120b (Fig. 2A) formed therethrough and having an opening 120o at a lower end. The drive mechanism 120d is configured to rotate the drive stem 123 relative to the top drive housing 120. In one embodiment, the drive mechanism 120d includes one or more actuators 1 10 (two shown), a first gear 121 , and a second gear 124. The actuators 1 10 may be disposed on the top of the top drive housing 120. The one or more actuators 1 10 may be hydraulic or electric motors. Each actuator 1 10 is rotationally coupled to an upper end of a respective first gear 121 . The first gear 121 may have a rotating shaft portion and a concentric geared portion disposed on the rotating shaft portion. The geared portion may have a greater diameter than the rotating shaft portion. The geared portion has gear teeth projecting outwards in a radial direction. The first gear 121 may be positioned adjacent to an inner surface of the top drive housing 120. Upper and lower ends of the first gear 121 may be supported by radial bearings 127 (Fig. 2A) disposed in a wall of the top drive housing 120. The radial bearings 127 facilitate rotational movement of the first gear 121 relative to the top drive housing 120. Alternatively, the drive mechanism 120d may be a direct drive motor coupled to the drive stem 123. The direct drive motor may be disposed in the top drive housing 120.

[0016] The second gear 124 is rotationally coupled to the first gear 121 . The second gear 124 may be disposed on an outer surface of the drive stem 123. The second gear 124 has a teeth profile for engagement with the gear teeth of the first gear 121 . The second gear 124 may have an outer diameter greater than the outer diameter of the drive stem 123. The drive stem 123 may be disposed in the bore 120b of the top drive housing 120. The drive stem 123 may be a shaft with a bore therethrough. The lower end of the drive stem 123 may have a threaded profile for connecting to a makeup tool 160 (Fig. 3). The bore of the drive stem 123 may provide for injection of drilling fluid from mud pumps (not shown) through the makeup tool 160 and into the tubular.

[0017] A carrier 125 is longitudinally coupled to the second gear 124 using a thrust bearing 122 (Fig. 2B). In this embodiment, the carrier 125 is positioned below the second gear 124 and the thrust bearing 122 in the top drive housing 120. The carrier 125 has a tubular shape with an upper bore 125u and a lower bore 125b. The lower bore 125b may have a greater diameter than the upper bore 125u. The carrier 125 may have a shoulder for receiving the thrust bearing 122. The drive stem 123 may pass through the bores 125u, 125b of the carrier 125. A radial bearing 128 (Fig. 2B) may be disposed between the carrier 125 and the drive stem 123 to allow the drive stem 123 to rotate with respect to the carrier 125 and the top drive housing 120. The radial bearing 128 may be disposed in the upper bore 125b of the carrier 125. A lower end of the carrier 125 may be longitudinally coupled to a bail housing 130 using a thrust bearing 132 (Fig. 2B) and nut 134 (Fig. 2B). The thrust bearing 132 and nut 134 may be disposed between an outer surface of the carrier 125 and an inner surface of the bail housing 130. The nut 134 may be received in a lower shoulder of the carrier 125, and locks the thrust bearing 132 in place. The carrier 125 may be rotationally locked to prevent rotation relative to the top drive housing 120, such as by a key and keyway.

[0018] The bail housing 130 may have a tubular shape with a bore 130b (Fig. 2B) therethrough. The drive stem 123 may pass through the bore 130b of the bail housing 130. In one embodiment, the bail housing 130 may have a brake to selectively lock rotation of the bail housing 130 relative to the carrier 125. The outer surface of the bail housing 130 may have hooks 133 (Fig. 2A) for receiving elevator links 131 . The elevator links 131 may have loops at both ends for connecting with the bail housing 130 at one end and an elevator 170 (Fig. 4) for gripping a tubular at the other end.

[0019] The carrier 125 is configured to support the weight of the drive stem 123 and the second gear 124, thereby allowing for axial movement of the thrust bearing 122, the second gear 124, and the drive stem 123 with the carrier 125. The thrust bearing 122 may transfer the load from the makeup tool 160 connected to the end of the drive stem 123 to the carrier 125. The carrier 125 may optionally be configured to also support the weight of the bail housing 130 and the elevator links 131 , thereby allowing for axial movement of the bail housing 130 and elevator links 131 with the carrier 125.

[0020] The carrier 125 is longitudinally coupled to one or more compensation cylinders 126. Compensation cylinders 126 may be electric, pneumatic, or hydraulic cylinders. Compensation cylinders 126 may be disposed between the carrier 125 and the top drive housing 120. Compensation cylinders 126 are operable to axially move the carrier 125 during the makeup or breakout of a tubular with a tubular string. The carrier 125 is axially movable between an upper position (Fig. 2A) and a lower position (Fig. 1 ). Axial movement of the carrier 125 also axially moves the second gear 124, drive stem 123, and thrust bearing 122 inside the top drive housing 120. Further, the carrier 125 can axially move these components 122-124 relative to the top drive housing 120.

[0021] A control circuit 140 may be used to accommodate various loads acting on the drive stem 123. In one embodiment, the control circuit 140 may be connected to the carrier 125 to allow for different loads to be raised. Alternatively, the control circuit 140 may be connected to the compensation cylinders 126.

[0022] The second gear 124 may axially move relative to the first gear 121 during makeup or breakout of the tubular connection. An axial profile length of the first gear 121 may be sufficiently long to allow the second gear 124 to remain rotationally coupled to the first gear 121 as the carrier 125 moves the drive stem 123 and the second gear 124 between the lower, extended position (Fig. 1 ) and the upper, retracted position (Fig. 2A). Alternatively, an axial profile length of the second gear 124 may be sufficiently long to allow the first gear 121 to remain rotationally coupled to the second gear 124 throughout the axial movement of the carrier 125 during makeup or breakout. The lower end of the drive stem 123 may be connected to a makeup tool 160, such as by a threaded coupling.

[0023] Alternatively, the lower end of the drive stem 123 may be connected to a multi-connection system ("MCS"), as disclosed in U.S. Patent Application No. 15/004390, filed on January 22, 2016, the portions of the specification describing and illustrating the various types MCS are incorporated herein by reference. In one example, the MCS includes a drive stem connectable with a tool dock. The tool dock may form part of a tool such that connection with the top drive may be facilitated using the MCS. Exemplary tools include a tubular makeup tool, casing tool, and cementing tool. The MCS may be configured to transfer power, torque, data, hydraulic connections, electric connections, and pneumatic connections to the makeup tool 160. The MCS may have junction members for connecting the hydraulic, electric, pneumatic, and data supplies from the top drive unit 100 to the makeup assembly 160.

[0024] The carrier 125 may extend from the bottom of the top drive housing 120 and be coupled to the bail housing 130. The bail housing 130 may be coupled to elevator links 131 (Fig. 1 ). The elevator links 131 may be coupled to a lifting device for lifting a tubular, such as an elevator. The carrier 125 (via compensation cylinders 126) may compensate the weight of the bail housing 130 and the lifting device (via elevator links 131 ) when lifting the tubular. The carrier 125 can axially move the bail housing 130 and the elevator links 131 , and the lifting device relative to the top drive housing 120.

[0025] Figure 2 is a schematic view of the top drive unit 100 with the drive stem

123 in an upper, retracted position. The carrier 125 actuates the drive stem 123 by compensation cylinders 126 to the upper, retracted position. [0026] Referring now to Figure 3, the top drive unit 100 is shown connected to a makeup tool 160 for makeup of a tubular 151 to a tubular string 150. The makeup tool 160 is connected to the lower end of the drive stem 123 and rotatable therewith. In operation, the top drive unit 100 is lowered to place the makeup tool 160 into engagement with the tubular 151 that is to be made up to the tubular string 150. In particular, the tubular 151 is gripped by the makeup tool 160 using, for example, slips. The makeup tool 160 may be configured to engage an internal surface of the tubular 151 or an external surface of the tubular 151. The tubular string 150 may be retained by a spider located on the rig floor.

[0027] The weight of the tubular 151 is transferred to the compensation cylinders 126 through the makeup tool 160, the drive stem 123, and the carrier 125. The compensation cylinders 126 are operable to reduce the amount of tubular weight that is set down on the threads of the tubular 151 and the tubular string 150 during the makeup or breakout process.

[0028] After gripping the tubular 151 , the top drive unit 100 moves the tubular 151 into position for threaded connection with the tubular string 150. The drive stem 123, second gear 124, and carrier 125 are in the upper, retracted position shown in Fig. 2A to begin the makeup process. Actuators 1 10 rotate the drive stem 123 by transferring torque via the rotational coupling between the first gears 121 and the second gear 124. In turn, the drive stem 123 transfers rotational movement to the tubular 151 to rotate the tubular 151 relative to the tubular string 150. During makeup, the compensation cylinders 126 may compensate for the downward travel of the tubular 151 due to the interaction between the threads by lowering the carrier 125, the second gear 124, and the drive stem 123. In this respect, the compensation cylinders 126 can reduce the load applied to the threads during makeup. Fig. 1 shows the carrier 125, the second gear 124, and the drive stem 123 in the lower, extended position. As the second gear 124 moves downward, it moves along the length of the first gear 121 and remains engaged with the first gear 121 to provide rotational movement to the drive stem 123. The length of the first gear 121 is configured to allow the second gear to remain in engagement through the makeup or breakout process. [0029] After the threaded connection of the tubular to the tubular string is complete, the top drive unit 100 may disengage the tubular by releasing the tubular from the makeup tool 160. The compensation cylinders 126 may return the carrier

125 to the upper, retracted position, as shown in Figure 2A. The makeup process may be repeated until the tubular string has reached the desired length.

[0030] In another embodiment, referring to Figure 4, an elevator 170 is shown connected to the top drive unit 100 during makeup of a tubular 151 with a tubular string. In particular, the elevator 170 is connected to the bail housing 130 via the hooks 133 of the elevator links 131. In operation, the top drive unit 100 is lowered to place the elevator 170 into engagement with the tubular 151 . The tubular 151 is retained by the elevator 170 using, for example, a load-bearing ring.

[0031] The weight of the tubular 151 is transferred to the compensation cylinders

126 through the elevator 170, the bail links 131 , the bail housing 130, the thrust bearing 132, the nut 134, and the carrier 125. The compensation cylinders 126 reduce the amount of tubular weight that is set down on the threads of the tubular 151 and the tubular string during the makeup or breakout process.

[0032] The top drive unit 100 moves the elevator 170 and the tubular 151 into position for threaded connection with the tubular string. The drive stem 123, second gear 124, carrier 125, bail housing 130, and elevator links 131 are in the upper, retracted position shown in Fig. 2A to begin the makeup between the tubular 151 and the tubular string. The tubular 151 is rotated using a tong assembly 180 (Fig. 4) to makeup the connection to the tubular string. The tong assembly 180 may be a power tong. During makeup, the compensation cylinders 126 may compensate for the downward travel of the tubular 151 due to the interaction between the threads by lowering the carrier 125, the second gear 124, the drive stem 123, and the bail housing 130. Fig. 1 shows the carrier 125, the second gear 124, the drive stem 123, the bail housing 130, and the elevator links 131 in the lower, extended position.

[0033] After the threaded connection is complete, the top drive unit 100 may disengage the tubular 151 by releasing the tubular 151 from the elevator 170. The makeup process may be repeated until the tubular string has reached the desired length.

[0034] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope of the invention is determined by the claims that follow.