TONG assembly position adjustment for threaded connection alignment

Abstract

An apparatus for positioning a tong assembly relative to a tubular can include a sensor attached to the tong assembly, a control system that processes data received from the sensor and thereby identifies a location of the tong assembly relative to an end of the tubular, and at least one actuator controlled by the control system and configured to displace the tong assembly. A method of positioning a tong assembly relative to a tubular can include obtaining an image of an end of the tubular with a camera attached to a tong assembly, processing the image, thereby identifying a location of the tong assembly relative to the tubular end, comparing the identified location with a desired location of the tong assembly relative to the tubular end, and displacing the tong assembly, thereby reducing a difference between the desired location and the identified location.

Description

[0001] Agent File Reference: WFT-6802-PCT

[0002] - 1 -

[0003] TONG ASSEMBLY POSITION ADJUSTMENT

[0004] FOR THREADED CONNECTION ALIGNMENT

[0005] TECHNICAL FIELD

[0006] This disclosure relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an example described below, more particularly provides for adjustment of a tong assembly position relative to a threaded connection.

[0007] BACKGROUND

[0008] Various types of tubular components can be threaded together to form tubular strings for use in a well. Tubulars used in wells can include protective wellbore linings (such as, casing, liner, etc.), production or injection conduits (such as, production tubing, injection tubing, screens, etc.), drill pipe and drill collars, and associated components (such as tubular couplings).

[0009] Threaded connections between tubulars are made-up during tubular running operations, and the threaded connections are broken-out when a tubular string is retrieved from a well. The make-up and break-out processes should be performed quickly, efficiently and safely.

[0010] It will, therefore, be readily appreciated that improvements are continually needed in the art of making-up and breaking-out threaded connections in tubular strings. The present disclosure provides such improvements to the art.

[0011] BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a representative partially cross-sectional view of an example of a well system and associated method which can embody principles of this disclosure. Agent File Reference: WFT-6802-PCT

[0013] - 2 -

[0014] FIG. 2 is a representative side view of an example tong assembly and apparatus for positioning the tong assembly relative to a tubular.

[0015] FIG. 3 is a representative front view of the tong assembly and apparatus.

[0016] FIG. 4 is a representative schematic view of an example of an image obtained using an optical sensor of the apparatus.

[0017] FIG. 5 is a representative flowchart for an example of a method of positioning the tong assembly relative to the tubular.

[0018] DETAILED DESCRIPTION

[0019] Representatively illustrated in FIG. 1 is a system 10 for use with a subterranean well, and an associated method, which can embody principles of this disclosure. However, it should be clearly understood that the well system 10 and method are merely one example of an application of the principles of this disclosure in practice, and a wide variety of other examples are possible. Therefore, the scope of this disclosure is not limited at all to the details of the well system 10 and method described herein and / or depicted in the drawings.

[0020] In the FIG. 1 example, a tubular string 12 is being assembled and deployed into a well. The tubular string 12 in this example is a production or injection tubing string, but in other examples the tubular string could be a casing, liner, drill pipe, completion, stimulation, testing or other type of tubular string. The scope of this disclosure is not limited to use of any particular type of tubular string, or to any particular tubular components connected in a tubular string.

[0021] As depicted in FIG. 1 , a tubular 14 is suspended near its upper end by means of a rotary table 16, which may comprise a pipe handling spider and / or safety slips to grip the tubular 14 and support a weight of the tubular string 12. In this manner, the upper end of the tubular 14 extends upwardly through a rig floor 18 in preparation for connecting another tubular 20 to the tubular string 12. Agent File Reference: WFT-6802-PCT

[0022] - 3 -

[0023] In this example, a tubular coupling 22 is made-up to the upper end of the tubular 14 prior to the tubular 14 being connected in the tubular string 12. The coupling 22 is internally threaded in each of its opposite ends.

[0024] In conventional well operations, it is common for a threaded together tubular and coupling to be referred to as a “joint” and for threaded together joints to be referred to as a “stand” of tubing, casing, liner, pipe, etc. However, in some examples, a separate coupling may not be used; instead one end (typically an upper “box” end of a joint) is internally threaded and the other end (typically a lower “pin” end of the joint) is externally threaded, so that successive joints can be threaded directly to each other.

[0025] Thus, the scope of this disclosure can encompass the use of a separate coupling with a tubular, or the use of a tubular without a separate coupling (in which case the coupling can be considered to be integrally formed with, and a part of, the tubular). In the FIG. 1 example, the coupling 22 can also be considered to be a tubular, since it is a tubular component connected in the tubular string 12.

[0026] To make-up a threaded connection 28 between the tubular 20 and the coupling 22, a set of tongs or rotary and backup clamps 24, 26 are used. The rotary clamp 24 in the FIG. 1 example is used to grip, rotate and apply torque to the upper tubular 20 as it is threaded into the coupling 22.

[0027] The backup clamp 26 in the FIG. 1 example is used to grip and secure the lower tubular 14 against rotation, and to react the torque applied by the rotary clamp 24. The rotary clamp 24 and the backup clamp 26 may be separate devices, or they may be components of a rig apparatus known to those skilled in the art as an “iron roughneck” or a tong assembly.

[0028] In one example, the rotary clamp 24 and backup clamp 26 may be components of a tong system, such as the VERO(TM) tong system marketed by Weatherford International, Inc. of Houston, Texas USA. In this example, the rotary clamp 24 may be a mechanism of the tong system that rotates and applies torque to the upper tubular 20, and the backup clamp 26 may be a backup Agent File Reference: WFT-6802-PCT

[0029] - 4 - mechanism of the tong system that reacts the applied torque and prevents rotation of the lower tubular 14.

[0030] Note that it is not necessary for the tubulars 14, 20 (and coupling 22, if used) to be vertical in the tubular make-up operation. The tubulars 14, 20 could instead be horizontal or otherwise oriented. Additional systems in which the principles of this disclosure may be incorporated include the CAM(TM), COMCAM(TM) and TORKWRENCH(TM) bucking systems marketed by Weatherford International, Inc.

[0031] After the upper tubular 20 is properly made-up to the lower tubular 14 or coupling 22, the tubular string 12 can be lowered further into the well, and the make-up operation can be repeated to connect another stand to the upper end of the tubular string. In this manner, the tubular string 12 is progressively deployed into the well by connecting successive stands to the upper end of the tubular string. In some examples, an individual tubular component may be added to the tubular string 12, instead of a stand.

[0032] In the FIG. 1 method, the rotary and backup clamps 24, 26 should be properly positioned respectively above and below the threaded connection, so that the rotary clamp can grip and apply torque to the upper tubular 20 and the backup clamp can grip the lower tubular 14 and react the torque applied to the upper tubular. Thus, the threaded connection 28 should be positioned vertically and laterally between the rotary and backup clamps 24, 26 in this example. In a make-up operation, however, the upper tubular 20 may not be present when the rotary and backup clamps 24, 26 are aligned with the coupling 22 or the upper end of the lower tubular 14.

[0033] An apparatus 30 is included in the FIG. 1 system 10 for appropriately positioning the rotary and backup clamps 24, 26 relative to the threaded connection 28. As described more fully below, the apparatus 30 can include one or more sensors for identifying a location of the threaded connection 28 and a control system that preferably adjusts a position of the rotary and backup clamps 24, 26 as needed automatically, so that a human presence on the rig floor 18 to perform these functions is unnecessary. Agent File Reference: WFT-6802-PCT

[0034] - 5 -

[0035] Referring additionally now to FIGS. 2 & 3, side and front views of an example of the apparatus 30 as used with a tong assembly 32 in the FIG. 1 system 10 and method is representatively illustrated. However, the apparatus 30 may be used with other tong assemblies, and other systems and methods, in keeping with the principles of this disclosure.

[0036] As depicted in FIGS. 2 & 3, the rotary and backup clamps 24, 26 are integrated as components of the tong assembly 32. In a make-up or break-out process, the threaded connection 28 should be positioned vertically and laterally between the rotary and backup clamps 24, 26. In the make-up process, the upper tubular 20 may not be present at the time the tong assembly 32 position adjustment is made, so an upper end 34 of the lower tubular 14 can be used as a reference instead, since the upper end 34 is also at the location where the threaded connection 28 will be made-up.

[0037] In the FIGS. 2 & 3 example, the apparatus 30 includes sensors 36, 38 for determining the location(s) of the tubular 14, the tubular 20, the threaded connection 28 and / or the upper end 34. The sensors 36, 38 may comprise any appropriate types of sensors, such as, optical sensors, cameras, lasers, terahertz scanners, acoustic sensors, etc. The apparatus 30 can also include a control system 40 to receive and process data output by the sensors 36, 38, and to control positioning and operation of the tong assembly 32.

[0038] As depicted in FIGS. 2 & 3, the sensors 36, 38 are mounted or attached to the tong assembly 32, so that the sensors are displaceable with the tong assembly. The sensors 36, 38 are positioned vertically between the rotary and backup clamps 24, 26 in the FIGS. 2 & 3 example. However, it is not necessary for the sensors 36, 38 to be positioned between the rotary and backup clamps 24, 26 in other examples.

[0039] At least the sensor 36 is also aligned with a desired location of the threaded connection 28 between the rotary and backup clamps 24, 26 in the FIG. 2 example. Thus, if it is desired for the threaded connection 28 to be positioned approximately halfway vertically between the rotary and backup clamps 24, 26, the sensor 36 can be positioned halfway vertically between the rotary and backup Agent File Reference: WFT-6802-PCT

[0040] - 6 - clamps. However, in other examples, the sensor 36 may not be aligned with the desired location of the threaded connection 28.

[0041] As depicted in FIGS. 2 & 3, the threaded connection 28 or the upper end 34 of the lower tubular 14 is positioned a certain height H above the rig floor 18. Thus, it is desired for the tong assembly 32 to be positioned, so that the rotary clamp 24 is vertically above that height H, and the backup clamp 26 is vertically below that height H.

[0042] An actuator 42 is operated by the control system 40 to adjust the vertical position of the tong assembly 32, so that the threaded connection 28 is vertically between the rotary and backup clamps 24, 26. Another actuator 44 may be operated by the control system 40 to displace the tong assembly 32 forward toward the tubular string 12, or rearward away from the tubular string. Additional actuators 48, 50 may be operated by the control system 40 to displace the tong assembly 32 laterally.

[0043] The actuators 42, 44, 48, 50 are depicted in FIGS. 2 & 3 as being hydraulic cylinders, but other types of actuators (such as, electrical, electromagnetic, fluid motor, pneumatic, etc.) may be used in other examples. The scope of this disclosure is not limited to use of any particular type, number or combination of actuators controlled by the control system 40.

[0044] Data output by the sensors 36, 38 is input to the control system 40. Image processing firmware and / or software of the control system 40 (for example, including artificial intelligence, neural networks, genetic algorithms, filters, etc.) can process the data to identify a location of the tong assembly 32 relative to the threaded connection 28 (including the tubular end 34). For example, the image processor 46 could identify a position of the threaded connection 28 in the data received from one of the sensors 36, 38.

[0045] A comparison can then be made as to whether there is a difference between the identified position of the threaded connection 28 and a desired position of the threaded connection. If there is a difference, the control system 40 can operate the actuator(s) 42, 44, 48, 50 as appropriate to reduce, minimize Agent File Reference: WFT-6802-PCT

[0046] - 7 -

[0047] (such as, within a certain distance tolerance) or completely eliminate the difference.

[0048] Referring additionally now to FIG. 4, a schematic view of an example of an image 52 obtained using an optical sensor 36 of the apparatus 30 is representatively illustrated. The image 52 comprises data representing an upper portion of the lower tubular 14 and a lower portion of the upper tubular 20. In a make-up process, the upper tubular 20 may not be represented in the image 52, but the upper portion of the lower tubular 14 (including the upper end 34) will preferably be represented in the image.

[0049] In this example, the sensor 36 comprises a camera, which outputs the digital image 52 of the threaded connection 28 (or at least the upper end 34 of the lower tubular 14). The image processor 46 is capable of identifying the location 54 of the threaded connection 28 or upper end 34 in the image 52. Since the sensor’s 36 frame of reference corresponds to a certain position of the sensor on the tong assembly 32 (the sensor being secured at a known position on the tong assembly, and being displaced with the tong assembly), the location 54 of the threaded connection 28 in the image 52 corresponds to a location of the tong assembly relative to the threaded connection or upper end 34 of the lower tubular 14.

[0050] The location of the tong assembly 32 relative to the threaded connection 28 or upper end 34 may be different from a desired location of the tong assembly relative to the threaded connection or tubular upper end. In FIG. 4, a horizontal datum line 56 is used to represent a desired vertical location of the tong assembly 32 relative to the threaded connection 28 or tubular upper end 34. In this example, there is a difference d between the location of the tong assembly 32 relative to the threaded connection 28, and the desired location of the tong assembly relative to the threaded connection or tubular upper end.

[0051] The control system 40 controls operation of the actuator 42 to adjust the vertical position of the tong assembly 32, until the difference d is reduced, minimized or completely eliminated. Preferably the control system 40 operates the actuator 42 automatically in response to comparing the identified location to Agent File Reference: WFT-6802-PCT

[0052] - 8 - the desired location and determining that there is a difference d in this example. However, in some examples, human intervention may be used to confirm that the tong assembly 32 should be displaced, prior to the control system 40 operating the actuator 42.

[0053] Although adjustment of the vertical position of the tong assembly 32 is described above, it will appreciated that similar adjustments may be made to the lateral and forward or rearward positions of the tong assembly 32, if desired, when there is a difference between identified and desired lateral or forward / rearward locations of the tong assembly relative to the threaded connection 28 or tubular upper end 34. For example, the control system 40 can operate the actuators 44, 48, 50 to reduce, minimize or eliminate any difference between the identified and desired lateral or forward / rearward locations of the tong assembly relative to the threaded connection 28 or tubular upper end 34.

[0054] Referring additionally now to FIG. 5, a method 60 of positioning a tong assembly relative to a tubular is representatively illustrated in flowchart form. The FIG. 5 method 60 may be used with the FIGS. 1-3 well system 10 and method, or it may be used with other systems and methods. For convenience, the method 60 is described below as it may be used with the FIGS. 1-3 well system 10 and method.

[0055] In an initial step 62 of the method 60, an evaluation is requested. The evaluation is to determine whether there is a difference d between the location of the tong assembly 32 relative to the threaded connection 28 or the tubular upper end 34, and the desired location of the tong assembly relative to the threaded connection or the tubular upper end. If the difference d does exist, or if the difference is greater than a satisfactory tolerance, the tong assembly 32 is displaced to reduce, minimize or eliminate the difference. The evaluation may be requested or initiated, for example, when a make-up or break-out process is initiated, or after an adjustment has been made to the position of the tong assembly 32 during a make-up or break-out process.

[0056] In step 64, an image of the threaded connection 28 or tubular upper end 34 is obtained. In the apparatus 30 described above, the optical sensor 36 Agent File Reference: WFT-6802-PCT

[0057] - 9 - comprises a digital camera that can output a digitized image 52. Preferably, the threaded connection 28 or the tubular upper end 34 is represented in the image 52.

[0058] In step 66, the image 52 is processed. In this example, the image processor 46 of the control system 40 receives the image data from the sensor 36 and processes the image 52 to identify the threaded connection 28 or tubular upper end 34 as represented in the image data. The identified location of the tong assembly 32 relative to the threaded connection 28 or tubular upper end 34 is compared to the desired location of the tong assembly relative to the threaded connection or tubular upper end, to thereby determine whether there is a difference d between them.

[0059] In step 68, a determination is made whether an adjustment of the tong assembly 32 position is needed. For example, an adjustment of the tong assembly 32 position may be needed if the difference d is non-zero, or outside of an acceptable tolerance range.

[0060] In step 70, the make-up or break-out process is continued and completed, if the determination made in step 68 is that adjustment of the tong assembly 32 position is not needed. In step 72, the method proceeds to the next threaded connection make-up or break-out. In this example, the method 60 repeats with each successive make-up or break-out process.

[0061] In step 74, the tong assembly 32 is displaced, if the determination made in step 68 is that adjustment of the tong assembly 32 position is needed. In this example, the control system 40 can automatically displace the tong assembly 32 (such as, by operating the actuators 42, 44, 48, 50) as needed to reduce, minimize or eliminate the difference d. In other examples, the actuators 42, 44, 48, 50 could be manually operated, or automatically operated after human confirmation.

[0062] If the determination made in step 68 is inconclusive or uncertain, then another evaluation is initiated (step 62). In addition, or alternatively, another evaluation may be initiated after the tong assembly 32 is displaced (step 74). Agent File Reference: WFT-6802-PCT

[0063] - 10 -

[0064] It may now be fully appreciated that the above disclosure provides significant advancements to the art of making-up and breaking-out threaded connections in a tubular string. In examples described above, the tong assembly 32 can be conveniently positioned relative to the threaded connection 28 or the tubular upper end 34, so that the threaded connection or tubular upper end is appropriately positioned between the rotary and backup clamps 24, 26.

[0065] The above disclosure provides to the art a method 60 of positioning a tong assembly 32 relative to a tubular 14. In one example, the method 60 can comprise: obtaining an image 52 of at least an end 34 of the tubular 14 with a camera 36 attached to the tong assembly 32; processing the image 52, thereby identifying a location of the tong assembly 32 relative to the tubular end 34; comparing the identified location with a desired location of the tong assembly 32 relative to the tubular end 34; and displacing the tong assembly 32, thereby reducing a difference d between the desired location and the identified location.

[0066] The displacing step may be performed automatically in response to the comparing step. The tubular end 34 may be at a threaded connection 28 between the tubular 14 and another tubular 20.

[0067] The displacing step may include a control system 40 controlling operation of at least one actuator 42, 44, 48, 50. The displacing step may further include the actuator(s) 42, 44, 48, 50 displacing the tong assembly 32 in one or more direction (such as, upward, downward and / or lateral).

[0068] The reducing step may include minimizing or eliminating the difference d between the desired location and the identified location.

[0069] The method 60 may include attaching the camera 36 to the tong assembly 32 between a rotary clamp 24 and a backup clamp 26 of the tong assembly 32.

[0070] The method 60 may include attaching the camera 36 to the tong assembly 32 at a position aligned with a desired location of the tubular end 34.

[0071] The displacing step may include displacing the camera 36 with the tong assembly 32. Agent File Reference: WFT-6802-PCT

[0072] - 11 -

[0073] The above disclosure also provides to the art an apparatus 30 for positioning a tong assembly 32 relative to a tubular 14. In one example, the apparatus 30 can comprise: a sensor 36, 38 configured to attach to the tong assembly 32; a control system 40 configured to process data received from the sensor 36, 38 and thereby identify a location of the tong assembly 32 relative to an end 34 of the tubular 14; and at least one actuator 42, 44, 48, 50 controlled by the control system 40 and configured to displace the tong assembly 32.

[0074] The sensor 36 may comprise an optical sensor. The optical sensor may comprise a camera.

[0075] The sensor 36, 38 may be attached to the tong assembly 32 between a rotary clamp 24 and a backup clamp 26 of the tong assembly 32.

[0076] The sensor 36, 38 may be displaceable with the tong assembly 32.

[0077] The sensor 36, 38 may be aligned with a desired location of the tubular end 34.

[0078] The control system 40 may be configured to automatically operate the at least one actuator 42, 44, 48, 50 in response to there being a difference d between the identified location and a desired location of the tong assembly 32 relative to the tubular end 34. The control system 40 may be configured to automatically operate the at least one actuator 42, 44, 48, 50 to reduce, minimize or eliminate a difference d between the identified location and a desired location of the tong assembly 32 relative to the tubular end 34.

[0079] The “at least one” actuator 42, 44, 48, 50 may be configured to displace the tong assembly 32 in one or more direction selected from upward, downward and lateral directions.

[0080] Although various examples have been described above, with each example having certain features, it should be understood that it is not necessary for a particular feature of one example to be used exclusively with that example. Instead, any of the features described above and / or depicted in the drawings can be combined with any of the examples, in addition to or in substitution for any of the other features of those examples. One example’s features are not mutually Agent File Reference: WFT-6802-PCT

[0081] - 12 - exclusive to another example’s features. Instead, the scope of this disclosure encompasses any combination of any of the features.

[0082] Although each example described above includes a certain combination of features, it should be understood that it is not necessary for all features of an example to be used. Instead, any of the features described above can be used, without any other particular feature or features also being used.

[0083] It should be understood that the various embodiments described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of this disclosure. The embodiments are described merely as examples of useful applications of the principles of the disclosure, which is not limited to any specific details of these embodiments.

[0084] In the above description of the representative examples, directional terms (such as “above,” “below,” “upper,” “lower,” “upward,” “downward,” etc.) are used for convenience in referring to the accompanying drawings. However, it should be clearly understood that the scope of this disclosure is not limited to any particular directions described herein.

[0085] The terms “including,” “includes,” “comprising,” “comprises,” and similar terms are used in a non-limiting sense in this specification. For example, if a system, method, apparatus, device, etc., is described as “including” a certain feature or element, the system, method, apparatus, device, etc., can include that feature or element, and can also include other features or elements. Similarly, the term “comprises” is considered to mean “comprises, but is not limited to.”

[0086] Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the disclosure, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to the specific embodiments, and such changes are contemplated by the principles of this disclosure. For example, structures disclosed as being separately formed can, in other examples, be integrally formed and vice versa. Accordingly, the foregoing detailed description is to be Agent File Reference: WFT-6802-PCT

[0087] - 13 - clearly understood as being given by way of illustration and example only, the spirit and scope of the invention being limited solely by the appended claims and their equivalents.

Claims

Agent File Reference: WFT-6802-PCT- 14 -WHAT IS CLAIMED IS:1 . A method (60) of positioning a tong assembly (32) relative to a tubular (14), the method comprising: obtaining an image of at least an end (34) of the tubular (14) with a camera (36) attached to the tong assembly (32); processing the image (52), thereby identifying a location of the tong assembly (32) relative to the tubular end (34); comparing the identified location with a desired location of the tong assembly (32) relative to the tubular end (34); and displacing the tong assembly (32), thereby reducing a difference (d) between the desired location and the identified location.

2. The method (60) of claim 1 , in which the displacing is performed automatically in response to the comparing.

3. The method (60) of claim 1 or 2, in which the tubular end (34) is at a threaded connection (28) between the tubular (14) and another tubular (20).

4. The method (60) of any preceding claim, in which the displacing comprises a control system (40) controlling operation of at least one actuator (42, 44, 48, 50), and optionally the at least one actuator (42, 44, 48, 50) displacing the tong assembly (32) in one or more direction selected from the group consisting of upward, downward and lateral.

5. The method (60) of any preceding claim, in which the reducing comprises minimizing or eliminating the difference (d) between the desired location and the identified location.Agent File Reference: WFT-6802-PCT- 15 -6. The method (60) of any preceding claim, further comprising attaching the camera (36) to the tong assembly (32) between a rotary clamp (24) and a backup clamp (26) of the tong assembly (32), or at a position aligned with a desired location of the tubular end (34).

7. The method (60) of any preceding claim, in which the displacing comprises displacing the camera (36) with the tong assembly (32).

8. An apparatus (30) for positioning a tong assembly (32) relative to a tubular (14), the apparatus comprising: a sensor (36, 38) configured to attach to the tong assembly (32); a control system (40) configured to process data received from the sensor (36, 38) and thereby identify a location of the tong assembly (32) relative to an end (34) of the tubular (14); and at least one actuator (42, 44, 48, 50) controlled by the control system (40) and configured to displace the tong assembly (32).

9. The apparatus (30) of claim 8, in which the sensor (36) comprises an optical sensor, and optionally in which the optical sensor comprises a camera.

10. The apparatus (30) of claim 8 or 9, in which the sensor (36, 38) is attached to the tong assembly (32) between a rotary clamp (24) and a backup clamp (26) of the tong assembly (32), and optionally in which the sensor (36, 38) is aligned with a desired location of the tubular end (34).11 . The apparatus (30) of any preceding claim, in which the sensor (36, 38) is displaceable with the tong assembly (32).Agent File Reference: WFT-6802-PCT- 16 -12. The apparatus (30) of any preceding claim, in which the control system (40) is configured to automatically operate the at least one actuator (42, 44, 48, 50) in response to there being a difference (d) between the identified location and a desired location of the tong assembly (32) relative to the tubular end (34).

13. The apparatus (30) of any preceding claim, in which the control system (40) is configured to automatically operate the at least one actuator (42, 44, 48, 50) to reduce a difference (d) between the identified location and a desired location of the tong assembly (32) relative to the tubular end (34).

14. The apparatus (30) of any preceding claim, in which the control system (40) is configured to automatically operate the at least one actuator (42, 44, 48, 50) to minimize a difference (d) between the identified location and a desired location of the tong assembly (32) relative to the tubular end (34).

15. The apparatus (30) of any preceding claim, in which the at least one actuator (42, 44, 48, 50) is configured to displace the tong assembly (32) in one or more direction selected from the group consisting of upward, downward and lateral.

Images