WO2008034262A1

WO2008034262A1 - Oilfield tubular torque wrench with automated positioning

Info

Publication number: WO2008034262A1
Application number: PCT/CA2007/001700
Authority: WO
Inventors: Douglas A. Hunter
Original assignee: Canrig Drilling Technology Ltd
Current assignee: Canrig Drilling Technology Ltd
Priority date: 2006-09-21
Filing date: 2007-09-21
Publication date: 2008-03-27
Anticipated expiration: 2009-03-21

Abstract

Apparatus and methods for automated positioning of an oilfield torque wrench with respect to the floor of a drilling rig are described. Angular encoders and linear transducers provide feedback with respect to the position of the torque wrench. The position feedback information may be processed through a variety of functions to smooth out changes in the motion control signals from the operator's control console sent to the torque wrench. The position feedback information may also be used to limit the motion of the torque wrench. Proportional flow valves are employed to control the pressure in hydraulic or pneumatic circuits. A learning function is employed for reading out and storing position information such as the angular encoder and liner transducer outputs, a position information recall function being employed for retrieval. A wireless console allows the operator to freely walk about the torque wrench while actuating it.

Description

OILFIELD TUBULAR TORQUE WRENCH WITH AUTOMATED POSITIONING

Field

The present invention generally relates to oilfield tubular torque wrenches used in handling make up or breakout of wellbore drill strings, and in particular to apparatus and methods for positioning the torque wrench with respect to the drill rig floor.

Background

Various types of tongs have been employed when making up or breaking out drill pipe joints, drill collars and the like in oil well drilling operations in which upper and lower tongs sequentially grip and release upper and lower drill pipe joints with the upper and lower tongs being moved in a swivelling or scissoring manner to thread or unthread the threaded connection between the drill pipe joints. Power operated tongs have been provided for this purpose.

In some torque wrenches, an upper and lower tong are swiveled with respect to each other by a torqueing cylinder which can be extended or retracted to break out or make up the drill pipe as may be required. A pipe biting or gripping system on each tong utilizes moveable die heads that include pipe gripping dies. The die heads may be moveable by various means including, for example, hydraulic rams that extend to move the die heads into gripping or biting engagement with the pipe. Components including, but not limited to: joints of drill pipe, drill collars, casing, casing collars, wellbore liners, subs drill bits, etc. are referred to herein as tubulars.

Oil rig crews make-up and break-out numerous connections between tubulars. Positioning the torque wrench about the tubular string, above the wellbore and a mouse hole, tends to be performed manually each time, using visual inspection to confirm adequate positioning. Considering that drill strings are made-up and broken-out a number of times to drill the well to a desired depth, manually positioning the torque wrench each time it incurs high operational overheads.

Summary

In accordance with a broad aspect of the present invention, there is provided an oilfield torque wrench comprising: a torque wrench including a lower tong and an upper tong; a support member for supporting the torque wrench above a drilling floor and for moving the torque wrench between a parked position and a position extending out over the drilling floor; a positional monitoring device to detect the position of the torque wrench above the drilling floor; and a control system to monitor the positional monitoring device to obtain a value for the extension of the torque wrench and for controlling the positioning of the torque wrench based on the value obtained.

In accordance with a broad aspect of the present invention, there is provided a method for operating an oilfield tubular torque wrench comprising: providing a torque wrench including an upper tong and a lower tong; providing an extendible support member to move the torque wrench over a drilling floor of a rig between a parked position and an extended well center operational position; recording in computer memory a parking position positional threshold value for the torque wrench at the parking position; obtaining reported positional values for the torque wrench during movement thereof; and controlling the wrench to stop at the parked position by comparing the reported positional values against the parking position positional threshold value and stopping the movement of the torque wrench when a reported positional value substantially equals the parking position positional threshold value.

In accordance with a broad aspect of the present invention, there is provided A control system for controlling a torque wrench, the torque wrench being supported above a drilling floor by a support member and drivable between a parked position and an extended well center operational position, the system comprising: a positional monitoring device for generating values relating to the position of the torque wrench; a monitoring function for monitoring the positional monitoring device and obtaining generated values therefrom; a system control function to control torque wrench movement; and a processing function for receiving inputs from the monitoring function and outputting directions to the system control function.

In accordance with a broad aspect of the present invention, there is provided an oil field torque wrench having automated positioning means.

In accordance with another broad aspect of the present invention, there is provided an oil field torque wrench having automated repositioning means.

In accordance with a further broad aspect of the present invention, there is provided an oil field torque wrench having automated positioning means configured to position the torque wrench above one of a well bore and a mouse hole.

In accordance with a further broad aspect of the present invention, an oil field torque wrench is provided with position feedback means including at least one of an angular encoder and a linear transducer reporting values thereof. In accordance with a further broad aspect of the present invention, there is provided an oil field torque wrench having a drilling information store for retrievably storing value reported by the position feedback means.

In accordance with a further broad aspect of the present invention, there is provided an oil field torque wrench applying at least one displacement smoothing or displacement limiting function to torque wrench positioning controls.

In accordance with a further broad aspect of the present invention, there is provided an oil field torque wrench employing a proportional flow valve to control pressure in hydraulic or pneumatic circuits.

In accordance with yet another broad aspect of the present invention, there is provided a wireless console for an oil field torque wrench enabling an operator to walk about the torque wrench while in operation.

It is to be understood that other aspects of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein various embodiments of the invention are shown and described by way of illustration. As will be realized, the invention is capable for other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present invention. Accordingly the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

Brief Description of the Drawings

Referring to the drawings wherein like reference numerals indicate similar parts throughout the several views, several aspects of the present invention are illustrated by way of example, and not by way of limitation, in detail in the figures, wherein: Figures IA and I B are perspective and top plan views, respectively, of a torque wrench mounted on a drill floor in an extended position.

Figures 2A and 2B are perspective views of a torque wrench with Figure 2A showing the torque wrench tongs in a neutral position and Figure 2B showing the torque wrench tongs in a torque up start position.

Figures 3A and 3B are side elevations of a torque wrench mounted on a drill floor, in a parked position and an extended position respectively.

Detailed Description of Various Embodiments

The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments contemplated by the inventor. The detailed description includes specific details for the purpose of providing a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.

While the invention is hereafter described utilizing hydraulically actuated power cylinders and hydraulic circuits therefor, it will be readily appreciated and understood by those skilled in the art that any one or all of such power cylinders of this invention can alternately be pneumatic and corresponding pneumatic circuits may be used in conjunction therewith. Alternately, screw drives or other drivers may be used.

The present invention generally relates to drill pipe torque wrench tongs used in making up or breaking apart oilfield tubular strings on the floor of a drilling rig. To facilitate understanding of drill pipe torque wrenches, it is noted that such devices often include hydraulically or pneumatically powered upper and lower tongs that are swivelly connected for a scissoring action. Each of the tongs includes dies that act to bite into or grip tubular string components to be handled.

Referring now specifically to Figures 1 A to 3B of the drawings, one embodiment of a power actuated drill pipe torque wrench of the present invention are generally designated by numeral 10. The torque wrench is illustrated in association with a drill rig floor 12. Torque wrench 10 is supported over the drill floor by a supporting member, which in this embodiment includes an arm 16 with a laterally extending arm extension 18 connected to the wrench. The support member may be mounted on or adjacent the drilling floor in various ways. For example, as shown, the supporting member may include a flange 19a that is secured as by bolts 19b onto the rig floor. Alternately, the supporting member may include a stem that may be inserted into a mounting hole on floor 12 or supporting member may be supported above the floor as by use of a post or other intermediate member.

The wrench is often associated with a spinner, generally designated by numeral 20, which is mounted above the wrench for spinning tubulars.

Torque wrench 10 includes an upper tong 22 and a lower tong 24 each of which may be substantially identical and which each include a horizontally disposed body 26 with a generally U-shaped recess 28 in an edge thereof to receive oilfield tubulars to be handled thereby including for example joints of drill pipe, drill collars, casing, wellbore liners, drill bits and the like. Recesses 28 are formed to act about an axis x.

In operation, the torque wrench is moved so that its recesses 28 are positioned about a tubular to be gripped, herein shown in phantom as tubulars 30 and 31. In the position to be gripped tubulars 30, 31 extend generally along an axis that is aligned with axis x through the recesses. Upper tong 22 may act on an upper tubular 30 and lower tong 24 may act on a lower tubular 31. The tubulars 30, 31 are shown in phantom to facilitate illustration. With the upper tong 22 gripping an upper tubular and the lower tong gripping a lower tubular, tongs 22, 24 may be swiveled relative to each other, which often includes holding one of the tongs stationary, while the other tong swivels relative thereto, to either torque up or break out a threaded connection between the tubulars.

Mounted on the body 26 in recess 28 is a plurality of dies 34 having pipe gripping teeth mounted thereon. In the illustrated embodiment, dies 34 are mounted on die heads 38 that are moveable, as by hydraulics 39, pneumatics, screw drives, etc., toward and away from axis x. As such, dies 34 may be moved into a gripping position or pulled back from a gripping position, as desired. The die heads are positioned in each recess 28 to act substantially diametrically opposite each other to act to grip a tubular therebetween.

Each die head 38 may have an angular or curved surface on which its dies 34 are mounted in spaced apart relation so that the dies are arranged along an arcuate path to generally follow the outer surface of a tubular 30 to be gripped, which outer surface is, of course, also generally acuate. The spaced, angular positioning may enable the dies 34 to engage spaced points on the circumference of the drill pipe or tool joint.

The upper tong 22 may swivel in relation to the lower tong 24 to move the tongs from a neutral position shown in Figures 1 and 2A to one of the make up or break out torqueing positions, the make up torquing start position of which is illustrated in Figure 2B. To permit the swiveling action, a driver such as double acting hydraulic piston and cylinder assembly 96 may be provided adjacent the end of the tong bodies 26 remote from the die heads 38 which interconnects the upper and lower tongs 22 and 24 so that by extending and retracting the torqueing piston and cylinder assembly 96 in timed relation to extension and retraction of the die heads, the upper and lower tubulars 30 and 31 may be gripped and torqued in a manner to make-up or break apart a threaded connection therebetween.

Extension and retraction of the piston and cylinder assembly 96 cause the upper and lower tongs 22 and 24 to move toward and away from the torqueing position illustrated in Figure 2B and into or through the neutral position shown in Figure

2A. That is, with the upper tong 22 either in alignment with the lower tong 24 or the upper tong 22 moved into angular position with respect to the lower tong 24 which is the torqueing position illustrated in Figure 2B, the tongs 22 and 24 are moved in a swivelling manner and after gripping them by use of dies, rotate one tool joint in relation to the other.

When the tongs are properly aligned with oilfield tubulars 30, 31 to be handled, a threaded connection therebetween is positioned between the dies 34 of upper tong 22 and the dies of lower tong 24 and the tubulars extend generally along axis x. In that position, die heads 38 of lower tong 24 may be actuated to grip therebetween lower tubular 31. Then, depending upon whether the threaded connection is being made up or broken apart, the torque piston and cylinder assembly 96 is extended or retracted. During the extension or retraction of the torque cylinder, the die heads 38 on the upper tong 22 will be in their retracted positions so that the upper tong 22 can rotate in relation to the upper tubular 40. Thus, with the upper tong 22 released and the torque piston and cylinder assembly 96 either extended or retracted to an initial position depending upon whether the drill pipe is being made up or broken out, the upper tong 22 may then be brought into gripping engagement with the upper tubular 30 by moving the die heads out to place the dies carried thereon into gripping relation with the tubular. After this has occurred, both the upper tubular 30 and the lower tubular 31 are securely gripped by the respective tongs. Then, the piston and cylinder assembly 96 is actuated for moving the upper and lower tongs 22 and 24 pivotally or swivelly in relation to each other thus torqueing the drill pipe joints 30 and 31 either in a clockwise manner or a counterclockwise manner depending upon whether the drill pipe is being made up or broken out. Co-pending commonly assigned PCT Patent Application serial no.s PCT/CA2006/001387, PCT/CA2OO6/OO1388 and PCT/CA2006/001406, filed August, 2006 describe aspects of torque wrenches, and are incorporated herein by reference.

Correct positioning of the torque wrench relative to a tubular being handled may be important for a number of reasons. For example, in using torque wrenches for making up/breaking out oilfield tubulars, it is desired that the torque wrench operate close, but not beyond, physical material limits of the tubulars, the rig, the torque wrench and the torque wrench dies. However, such physical material limits are difficult to predict and typically vary with environmental parameters. In one situation for example, it is desired that the torque wrench be operated below a condition where the dies slip on the tubular being handled. Die slippage may be indicative of worn dies, or other problems, but can also occur when the dies are not properly oriented to grip the pipe.

Also, efficient and directed movements, including correct positioning, of the torque wrench can speed and facilitate pipe handling.

A drilling floor 12 generally has a fixed well center location WC and may include other fixed locations such as the mousehole. In addition, in the illustrated embodiment, the torque wrench support member may be mounted at a fixed location on the drilling floor, as determined by the mounting structure such as flange 19a.

The location of the torque wrench relative to fixed spots, such as well center, on drilling floor 12 may be described in terms of an angular displacement A, the extension B of arm 16, including extension 18, and the vertical displacement C of the torque wrench relative to its mount on extension 18. A tubular to be gripped generally will be in a fixed location on the drilling floor extending up substantially vertically at well center or in the mouse hole. Although the vertical position of a tubular at well center may not vary significantly, the height of the tool joint, and therefore the height of the interface at the threaded connection between the upper and lower tubulars may vary.

In one embodiment of the invention, arm 16 may be rotated on its mount, such as a rotary bearing therein, on the drilling floor 12 by a motor 302. Motor 302 drives arm 16 and therefore wrench 10 to pivot about a vertical axis through the floor. Angular displacement A may be measured from an angular origin 300, as the torque wrench 10 is rotated by motor 302. The angular displacement may be measured in various ways, as by use, for example, of an angular encoder 304 on the motor. The angular origin may be any known position. For example, angular original may be a line extending between the mounting location of arm 16 to well center.

The extension of arm 16 relative to its mounting position on the drilling floor corresponds to extension B. In the illustrated embodiment, arm 16 includes a linkage form between hinges between arm 16 and its mount and between the arm and extension 18. Using this linkage form arm 16 may be extended over the drilling floor 12 a length corresponding to extension B. A hydraulic cylinder 310 may be used to control the inclination of arm 16, the displacement of a drive rod 314 of the cylinder determining the degree of extension B. A linear transducer 312 may be used to measure the displacement of drive rod 314 of cylinder 310. As will be appreciated, extension of drive rod 314 increases extension of the arm and therefore an increase in the length of extension B and conversely when drive rod 314 is withdrawn; the length of extension B is decreased. Tongs 22/24 and the spinner attached thereto may be pivot about axis y, as by gravity acting on the center of gravity of wrench 10, to maintain a substantially vertical orientation of axis x. Vertical displacement C may be varied by movement of the torque wrench 10, including tongs 22, 24, relative to extension 18. Vertical displacement C acts to position the tongs 22, 24 to be in a position to grip a pairs of tubulars on either side of the threaded connection between them. In one embodiment, this vertical displacement may be varied by use of a telescopic member including a first slide 324 connected to extension 18, for example through bracket 320 and a second slide 323, telescopically disposed in first slide 324 and connected, for example through bracket 325, to wrench 10. Sliding movement between slides 323, 324 may be driven by a hydraulic cylinder acting therebetween, which in this illustrated embodiment is positioned within the slides and cannot be seen in this view. The vertical displacement C may be monitored by various devices, such as for example, a sensor, such as a proximity switch 321 , which may be positioned to identify when the torque wrench is in an appropriate position, such as in a fully elevated position relative to extension 18. Alternately, vertical displacement may be monitored by a measuring device such as by a linear transducer 322 as the member 323 moves with respect to bracket 320.

In accordance with an implementation of the embodiment of the invention, linear transducers may include linear variable transducers, without limiting the invention thereto.

In one embodiment, any or various combinations of the variables A, B and C may be used to determine the wrench position. For example, as motor 302, piston 314, and members 323, 324 move the arm and the wrench, the monitoring devices, such as angular encoder 304 and linear transducers 312 and 322 may provide feedback in the form of reported values corresponding to the position of the torque wrench 10.

A torque wrench control system may be provided for automated positioning and repositioning of the torque wrench. The control system may include an information store, such as for example a computer memory, for storage of reported values, a monitoring function to read outputs from monitoring devices such as encoders, linear transducers, proximity switches, etc., a system control function to control the torque wrench operation, for example, including control of the hydraulic drive systems, pumps, valves, etc. and a processing function for receiving inputs and outputting control functions. The control system may take various forms such as a computer, programmable logic controller, etc.

The angular value reported by angular encoder 304 and the linear displacement values reported by linear transducers 312 and 322 when the torque wrench 10 is in a parked position away from well center, Figure 3 A, may be considered as a "zero" position. These values may be read, as by logic, electronic or other means, and stored. With the torque wrench 10 accurately positioned over the well center, Figures I A and 3B, the outputs of the angular encoder 304 and the linear displacement values reported by the linear transducers 312 and 322 may be read and may be stored. Such values may be stored in records for a parked position and a well center operational position in a drilling information store, such as in manual or computer logic storage records. In accordance with another implementation of the embodiment of the invention, only the read out values of selected ones of the angular encoder 304, linear transducer 312 or linear transducer 322 may be of interest and stored in the well bore position record in the drilling information store.

Generally, for regular tripping operations, the torque wrench may be mounted to simply cycle between a parked position and an extended position, directly linearly moved from the parked position, such that the value related to extension B, that of linear transducer 312 in the present embodiment, is of greatest interest with respect to wrench positioning. The value along C during pipe handling at well center may generally be manually controlled to accommodate the variances in the position of the threaded connection, as described hereinbefore. The extension value along C may also be of interest in this operation, in order to ensure that the torque wrench is not driven against the drilling floor during retraction of the arm. However, a monitoring device such as proximity switch 321 may be used in this regard, rather than a more complex linear transducer. To obtain the values for any of A, B and C₁ the operator may drive the torque wrench to a position of interest, such as the parked position, the extended to well center operational position, etc. and various device readings can be made and recorded. The operator may position the wrench by use of wrench positioning controls.

If desired, the operator may further interact with the torque wrench positioning controls to position the torque wrench 10 over the mouse hole or into a fully withdrawn position (i.e. a position where the arm fully folded and rotated as far as possible from well center to leave room for other tools at well center). With the torque wrench 10 accurately in these positions, the positional values can be determined and stored in records associated with the various positions. For example, for a position over the mouse hole, one or more of the outputs of the angular encoder 304 and the linear displacement values reported by the linear transducers 312 and 322 are read out and may be stored in a mouse hole position record in the drilling information store. In accordance with the other implementation of the embodiment of the invention, only the read out value of the angular encoder 304 and the read out value of linear transducer 312 may be stored in the mouse hole position record in the drilling information store.

Subsequent to the storage of positional values corresponding to any of the positions of parked, well center, fully withdrawn and mouse hole, the operator may interact with the torque wrench controls to select any desired position for the torque wrench and the positional information relating to that torque wrench may be retrieved from the drilling information store and used by the control system to automate to some degree, the operation of the torque wrench. The values generated from the positional monitoring devices may be monitored to determine the position of the torque wrench and movement may be stopped when a value reported (i.e generated by the device and obtained by the control system) is compared and is found to be substantially equal with the stored positional values. The positional monitoring devices may be substantially continuously monitored or set to report such that they provide feedback on the wrench location.

The control system, with reference to stored information and with reference to actual positional values being determined, may offer automatic control or operator control with automatic limiting. For example, the control system may reference the stored positional values as position threshold values. In one embodiment, for example, using position threshold values based on retrieved stored position values, and an operator may actuate the torque wrench controls manually until at least one of the positional value thresholds is substantially met, as determined by the control system, at which point the control system may prevent further drive of the torque wrench along the limited direction of movement. For example, the operator, using the torque wrench controls, may drive the torque wrench until angular encoder 304, linear transducer 312 and/or transducer 322 reported values substantially equal the corresponding position threshold values, at which time the motor or cylinder having reached the position threshold values would be shut down. Alternately, an operator may drive the torque wrench under control by the control system by, for example, requesting power to be delivered to the motor 302, cylinder 310 (and vertical translation means) until the reported values of the angular encoder 304, linear transducer 312 and/or transducer 322 substantially equal the recorded position values corresponding to any position of interest.

In accordance with an implementation of the embodiment of the invention, the torque wrench controls may include a joystick, a positional selector such as a touch screen, a button, a knob, etc.

In practice it has been found that increasing the speed with which the hydraulics are actuated results in abrupt starts and stops which may potentially lead to unnecessary wear and tear. The control system, considering threshold position values, can be used to provide soft start and/or soft stop functions. For example, the control system may monitor actual reported values from the monitoring devices and when a value approaches a positional threshold value, the control system may regulate operation of the torque wrench drivers to ramp down the speed of the drive. In one embodiment, for example, a proportional flow valve may be used in the hydraulic circuit of cylinder 310 wherein feedback from the linear transducer 312 is employed to control the hydraulic pressure in the hydraulic circuit using the proportional flow valve. In accordance with an implementation of the embodiment of the invention, the difference between the value reported by the linear transducer 312 and the corresponding position threshold value may be employed to actuate the proportional flow valve. In accordance with another implementation of the embodiment of the invention, a function may be applied to the difference between the value reported by the linear transducer 312 and the corresponding position threshold value in controlling the proportional flow valve. With feedback from linear transducer 312, the hydraulic fluid flow may be ramped up to high speed and ramped down when nearing the threshold position value in a controlled manner thereby reducing operational time overheads while minimizing wear and tear.

Considering the operator actuatable torque wrench controls, such as a joystick. When actuated manually, the force applied or the degree to which the control is actuated by the operator, for example the degree of joystick deflection, may be used to control the proportional flow valve subject to the feedback from the linear transducer 312 and the corresponding position threshold value when set. The torque wrench 10 may speed up when the degree of joystick deflection is large up to a maximum speed after which the piston 314 moves at a constant speed until the difference between the value reported by the linear transducer 312 and the position threshold value set overrides the effect of the joystick deflection. In accordance with the embodiment of the invention, allowing the joystick to return to its neutral position may not result in an immediate closure of the proportional flow valve but rather a second function having a gradual dropdown characteristic may be applied to smooth out the sudden joystick release and provide a soft stop for the torque wrench. Subsequent to the selection of one of the well bore and the mouse hole positions, automatic positioning of the torque wrench 10 may be provided by actuating a control at the operator's console, without limiting the invention, for example by double clicking the joystick and letting go, wherein a ramp-up function responsive to the double clicking action may be employed to ramp up hydraulic flow via the proportional flow valve, and a ramp-down function may be applied to gradually reduce the hydraulic fluid flow via the proportional flow valve responsive to the difference between the value reported by the linear transducer 312 and the value of the position threshold set.

In accordance with another implementation of the invention, further overhead reductions may be gained by enabling the operator to freely walk about the drill site, while operating the torque wrench 10 as by use of a wireless device with torque wrench controls thereon. This may enable the operator to be on the drilling floor, so that the entire torque wrench and tubular condition can observed, which is otherwise hard to do from the cabin where the drilling console is generally located.

In accordance with an implementation of the embodiment of the invention, the operator may be provided with a wireless console, typically embodying a portable wireless device incorporating controls otherwise integrated into the operator's console in the cabin. The portable wireless device may be worn around the operator's neck, over the shoulder, around the waist, etc.

With reference to Figures 3 A and 3B, a torque wrench is shown in parked and extended positions, respectively, relative to well center WC. In the embodiments of Figures 3A and 3B, many of the torque wrench and arm components are substantially similar to those described in reference to Figure 1 , as indicated by the use of corresponding reference numerals. However, it is noted that arm 16 is driven by a second hydraulic cylinder 410 acting between arm 16 and extension 18. Second hydraulic cylinder 410 may include a linear transducer 412 that measures extension of drive rod 414. The second hydraulic cylinder and liner transducer 412 may be monitored and controlled by an automated torque wrench positioning system, as desired, in addition or alternatively to cylinder 310.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to those embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the full scope consistent with the claims, wherein reference to an element in the singular, such as by use of the article "a" or "an" is not intended to mean "one and only one" unless specifically so stated, but rather "one or more". All structural and functional equivalents to the elements of the various embodiments described throughout the disclosure that are known or later come to be known to those of ordinary skill in the art are intended to be encompassed by the elements of the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 USC 1 12, sixth paragraph, unless the element is expressly recited using the phrase "means for" or "step for".

Claims

I claim:

1. An oilfield torque wrench comprising: a torque wrench including a lower tong and an upper tong; a support member for supporting the torque wrench above a drilling floor and for moving the torque wrench between a parked position and a position extending out over the drilling floor; a positional monitoring device to detect the position of the torque wrench above the drilling floor; and a control system to monitor the positional monitoring device to obtain a value for the extension of the torque wrench and for controlling the positioning of the torque wrench based on the value obtained.

2. An oilfield torque wrench of claim 1 wherein the positional monitoring device detects the degree to which the torque wrench is extended over the drill floor.

3. An oilfield torque wrench of claim 1 wherein the positional monitoring device detects the rotational position of the torque wrench on the drilling floor.

4. An oilfield torque wrench of claim 1 wherein the positional monitoring device detects the position of the torque wrench relative to the support member.

5. An oilfield torque wrench of claim 1 further comprising a hydraulic cylinder to drive the support arm to be retracted and extended and wherein the positional monitoring device includes a linear transducer mounted to detect the extension of the hydraulic cylinder and the control system monitors the linear transducer to obtain the value for the extension of the hydraulic cylinder.

6. An oilfield torque wrench of claim 1 further comprising a floor mount for the supporting member including a rotary bearing and a motor for driving the support member to rotate on the rotary bearing and wherein the positional monitoring device detects the rotational position of the support member.

7. An oilfield torque wrench of claim 1 further comprising a proximity switch acting between the torque wrench and the supporting member to determine a position wherein the torque wrench is at an uppermost position supported on the supporting member and the control system monitors the proximity switch.

8. An oilfield torque wrench of claim 1 wherein the control system includes an information store capable of storing a recorded value output by the positional monitoring device at the parked position and the control system further is operable to move the supporting member until the value obtained is substantially equal to the recorded value.

9. A method for operating an oilfield tubular torque wrench comprising: providing a torque wrench including an upper tong and a lower tong; providing an extendible support member to move the torque wrench over a drilling floor of a rig between a parked position and an extended well center operational position; recording in computer memory a parking position positional threshold value for the torque wrench at the parking position; obtaining reported positional values for the torque wrench during movement thereof; and controlling the wrench to stop at the parked position by comparing the reported positional values against the parking position positional threshold value and stopping the movement of the torque wrench when a reported positional value substantially equals the parking position positional threshold value.

10. A method for operating an oilfield tubular torque wrench of claim 9 further comprising recording in computer memory a well center positional threshold value for the torque wrench at the extended well center operational position; and controlling the wrench to stop at the extended well center operational position by comparing the reported positional values against the well center positional threshold value and stopping the movement of the torque wrench when a reported positional value substantially equals the well center positional threshold value.

1 1. A method for operating an oilfield tubular torque wrench of claim 10 wherein controlling includes moving the wrench from the parked position toward the extended well center operational position in response to an operator input.

12. A method for operating an oilfield tubular torque wrench of claim 9 wherein controlling further comprises slowing movement of the torque wrench when a reported positional value approaches the parked position positional threshold value.

13. A control system for controlling a torque wrench, the torque wrench being supported above a drilling floor by a support member and drivable between a parked position and an extended well center operational position, the system comprising: a positional monitoring device for generating values relating to the position of the torque wrench; a monitoring function for monitoring the positional monitoring device and obtaining generated values therefrom; a system control function to control torque wrench movement; and a processing function for receiving inputs from the monitoring function and outputting directions to the system control function.

14. A control system of claim 13 further comprising an information store to store a positional threshold value against which the generated values may be compared by the processing function.

15. A control system of claim 13 wherein the positional monitoring device includes a linear transducer for a hydraulic cylinder connected to drive extension of the support member.

16. A control system of claim 13 wherein the positional monitoring device includes an angular encoder for a motor connected to drive rotation of the support member.