Backup wrench for power tong

Abstract

The invention relates to a backup wrench for a power tong. The backup wrench comprises a wrench head jaw, a wrench body, and measuring means for measuring torque, wherein the wrench head jaw is pivotable with respect to the wrench body, and the measuring means is actuatable upon pivoting the wrench head jaw with respect to the wrench body.

Description

[0001] Backup wrench for power tong

[0002] The present invention relates to a backup wrench for a power tong, a backup wrench assembly for a power tong, a method of assembling a backup wrench, and the use of a backup wrench.

[0003] In mature oil fields, it may be necessary to promote the production of a hydrocarbon well. A common way of promoting this production is to introduce to the well a positive displacement pump, such as a reciprocating pump, downhole that is connected to driving means, such as a pump jack, at the surface level of the well. The reciprocating pump is connected to the driving means via a string of sucker rods.

[0004] The string is formed by a multitude of sucker rods that are connected to each other by means of threaded connections. The threaded connections comprise a first threaded connection member that is provided at a first longitudinal end of a sucker rod, and a second threaded connection member that is provided at a second longitudinal end of another sucker rod. In some cases, the first threaded connection member has a first thread on its outer circumferential surface, and the second threaded connection member has a second thread on its inner circumferential surface, wherein the first and second threads correspond to facilitate rotational engagement with each other. In other cases, the threaded connection further comprises a coupling with at a first longitudinal coupling end a first threaded coupling member with a first coupling thread, and at a second longitudinal coupling end opposite to the first longitudinal coupling end a second threaded coupling member with a second coupling thread. In this case, the first threaded connection member has a first thread that corresponds with the first coupling thread to facilitate rotational engagement, and the second threaded connection member has a second thread that corresponds with the second coupling thread to facilitate rotational engagement. The first and second coupling thread may be provided on the inner circumferential surface of the first and second threaded coupling members of the coupling, wherein the first and second thread of the first and second threaded connection members are provided on the outer circumferential surface of the first and second threaded connection members.

[0005] To connect (or make-up) the sucker rods with each other, a power tong in combination with a backup wrench may be used. A first sucker rod is lowered into the well and held in place with the first threaded connection member pointing upwards, wherein rotational movement

[0006] 17051835.JCP2.JCP2 of this lower sucker rod is prevented by means of the backup wrench. A second sucker rod is positioned above the lower sucker rod with the second threaded connection member pointing downwards, wherein this upper sucker rod is held in place with a jaw of the power tong. A coupling may be provided on either of the lower and upper sucker rods. The sucker rods are then brought towards each other, wherein the jaw of the power tong is actuated to rotate the upper sucker rod with respect to the lower sucker rod wherein a threaded connection between the sucker rods is formed.

[0007] When making up the sucker rods, it is important that the correct amount of torque is applied. Too much torque may yield the threads, causing permanent deformations at the threads, whereas too little torque might result in inadvertent disengagement of the sucker rods during operation.

[0008] To determine whether the sucker rods have been made up correctly, the sucker rods and / or coupling may have on the outer circumferential surface thereof a make-up mark. The marks are used to obtain an indication about whether or not the sucker rods have been made up correctly. For example, if the mark of the lower sucker rod is within a certain allowable distance from the mark of the upper sucker rod, the sucker rods have been made up correctly.

[0009] This way of determining whether the sucker rods have been made up correctly is, however, inefficient. In particular, dedicated measuring tools are required that are fitted to the specifications (e.g. diameter, allowable deviation between the marks, etc.) of the sucker rods, and the act of measuring takes up time that could have been spent differently. Moreover, the accuracy of the resulting measurements may differ from operator to operator.

[0010] To meet demands of the high-end market, more sophisticated power tongs are available. These sophisticated power tongs are outfitted with measuring equipment to measure the amount of torque applied by the power tong.

[0011] Although these power tongs take away the need to measure manually, they generally come with many features and functionalities to meet higher market demands. As such, these power tongs tend to be relatively expensive, and less abundantly available. Moreover, these power tongs tend to have a complex structure with many interconnected parts. As

[0012] 17051835.JCP2.JCP2 such, it can be difficult to replace broken or worn parts, wherein a considerable amount of skill is needed to do so.

[0013] This complexity becomes in particular relevant in cases where the measuring equipment has to be serviced and / or does not function properly and the hydrocarbon well is located at a difficult to reach location.

[0014] It is an object of the present invention to provide an improved, or at least alternative solution with respect to the prior art. In particular, it is an object of the present invention to provide a solution, wherein operating a power tong is more efficient and less complex.

[0015] The object is achieved in a first aspect in accordance with the present invention with a backup wrench for a power tong, comprising: a wrench head jaw, a wrench body, and measuring means for measuring torque, wherein:

[0016] -- the wrench head jaw is pivotable with respect to the wrench body, and

[0017] -- the measuring means is actuatable upon pivoting the wrench head jaw with respect to the wrench body.

[0018] The present invention provides an easy to use modular solution to the problems of the prior art. As the measuring means is located on the backup wrench, all torque measuring equipment can be provided to the power tong by assembling the backup wrench with the power tong, and taken away from the power tong by removing the backup wrench from the power tong, respectively. This way, it is possible to enable existing power tongs to conduct torque measurements. In addition, installation and / or replacement of the measuring means can be performed with few structural adjustments to the power tong. Accordingly, the present invention is more efficient and less complex.

[0019] Moreover, the backup wrench in accordance with the present invention is pre-assembled with the measuring means. In the event that the measuring means does not function properly, the operator has a strong indication that something is wrong with the backup wrench. The backup wrench can then simply be replaced, wherein downtime at the well is limited.

[0020] 17051835.JCP2.JCP2 Even further, the present invention enables efficient logistics. To meet certain quality standards, it may be required to have a power tong, including the torque measuring equipment, (re)certified. With the present invention, it is possible to have the backup wrench with the measuring means certified apart from a power tong. As such, (re)certification of the measuring means can be done with fewer parts. Accordingly, the invention allows to have less demanding, and cheaper logistics when (re)certification of the measuring means of a power tong is required.

[0021] By providing a backup wrench wherein the wrench head jaw is pivotable with respect to the wrench body, and the measuring means is actuatable upon pivoting of the wrench head jaw with respect to the wrench body, torque received at the wrench head jaw is directly transferred to the measuring means. Accordingly, it is possible to accurately measure torque applied, in particular to the lower sucker rod.

[0022] The backup wrench may comprise a wrench head comprising the wrench head jaw. The wrench head may be connected to the wrench body. In particular, the wrench head is integrally formed with the wrench body. In other words, the wrench head and the wrench body may be made of a single piece of material, in particular steel, or cast iron.

[0023] The wrench head jaw may be configured for engaging the non-circular portion of a sucker rod. In particular, the wrench head jaw may define a sucker rod rotation axis position for positioning the longitudinal axis of a sucker rod. The wrench head jaw and the wrench body may be pivotable about the sucker rod rotation axis at the sucker rod rotation position.

[0024] In particular, the measuring means is arranged between the wrench head jaw and the wrench body. The measuring means may be provided at the wrench head jaw or at the wrench body. Preferably, the measuring means is provided at, in particular on, the wrench body. More in particular, the measuring means may be connected to the wrench body. The measuring means may be arranged to measure torque in tangential direction with respect to the sucker rod rotation axis.

[0025] The measuring means as described in the present document may comprise an analogue sensor, or a digital sensor. In particular, the measuring means is adapted to measure torque applied by a power tong to a sucker rod by measuring torque received, via the

[0026] 17051835.JCP2.JCP2 sucker rods, at the backup wrench. In particular, the torque is measured during the makeup process.

[0027] The measuring means may be configured for measuring a torque indicator. The torque indicator may relate, for instance, to a material deformation, a relative movement of parts, or a hydraulic pressure change. Preferably, the measuring means converts the torque indicator into an electrical output signal. The electrical output signal may change in proportion to the measured torque indicator. More in particular, the measuring means may comprise a Wheatstone bridge, wherein the electrical output signal is an electric pressure.

[0028] The measuring means may comprise an actuation element and an actuation element housing. The actuation element may comprise a pin, wherein relative movement of the actuation element with respect to the actuation element housing provides the torque indicator. The actuation element may be actuatable in tangential direction with respect to the sucker rod rotation axis defined by the wrench head jaw.

[0029] Embodiments in accordance with the first, a second, a third, and a fourth, aspect of the present invention are described in the following.

[0030] In an embodiment of the first aspect in accordance with the present invention, the wrench head jaw defines a sucker rod rotation axis for positioning the longitudinal axis of a sucker rod. In particular, the wrench head jaw may define a sucker rod rotation axis position through which the sucker rod rotation axis extends. The sucker rod rotation axis may be vertical when engaging a sucker rod at the well.

[0031] In an embodiment of the first aspect in accordance with the present invention, the wrench head jaw is pivotable with respect to the wrench body about the sucker rod rotation axis. As such, the wrench head jaw and the wrench body share a rotation axis which rotation axis is the sucker rod rotation axis.

[0032] In an embodiment of the first aspect in accordance with the present invention, the measuring means is actuatable in tangential direction with respect to the sucker rod rotation axis.

[0033] 17051835.JCP2.JCP2 In an embodiment of the first aspect in accordance with the present invention, the measuring means comprises an actuation element and an actuation element housing, wherein the actuation element is actuatable upon pivoting of the wrench head jaw with respect to the wrench body. In particular, the actuation element is movable with respect to the actuation element housing.

[0034] In an embodiment of the first aspect in accordance with the present invention, the wrench head jaw comprises an actuation arm arranged to actuate the measuring means. In particular, the wrench head jaw may comprise a wrench head jaw body defining the sucker rod rotation axis position, wherein the actuation arm extends from an actuation arm first end adjoining the wrench head jaw body to an actuation arm second end opposite to the actuation arm first end. The wrench head jaw body may be integrally formed with the actuation arm.

[0035] In an embodiment of the first aspect in accordance with the present invention, the actuation arm comprises an actuation arm contact face for contacting the measuring means, wherein the actuation arm contact face is flush to a plane containing the sucker rod rotation axis. In particular, the actuation arm contact face is provided at the actuation arm second end. In such embodiment, the measuring means may comprise an actuation element with an actuation element contact face for contacting the actuation arm contact face. The actuation element contact face may also be flush to the plane containing the sucker rod rotation axis.

[0036] An advantage of the above embodiments is, that torque measurements may be relatively accurate. In addition, in embodiments wherein torque is measured in a plane containing the sucker rod rotation axis it may be relatively easy to determine torque values.

[0037] In an embodiment of the first aspect in accordance with the present invention, the backup wrench further comprises a mounting member for mounting the backup wrench to a backup wrench mount of a power tong, wherein the measuring means is located away from the mounting member.

[0038] In an embodiment of the first aspect in accordance with the present invention, the mounting member is integrally formed with the wrench body. In particular, the mounting member is integrally formed with the wrench body and the wrench head.

[0039] 17051835.JCP2.JCP2 An advantage of an integrally formed backup wrench is that the backup wrench may be less susceptible to damage. As such, the backup wrench is less likely to be damaged, wherein it is less likely that the backup wrench needs to be replaced. In particular, the backup wrench is adapted to sustain a torque of 100 to 10000 pound-foot (Ib-ft).

[0040] In an embodiment of the first aspect in accordance with the present invention, the mounting member comprises a mounting hole for receiving a mounting part. The mounting hole, may be a through hole. The mounting hole comprises a mounting hole axis. The mounting hole axis preferably extends in a torque application direction. In other words; the mounting hole may extend perpendicular to the sucker rod rotation axis and perpendicular to the longitudinal axis of the backup wrench. In particular, the mounting hole axis may extend tangential to the rotational torque received at the backup wrench. This way, rotation of the backup wrench about the mounting member may be prevented.

[0041] An advantage of the above embodiments is that the measuring means can function independently from the mounting member. This allows design freedom with respect to the mounting member. In particular, the mounting member can be customized to comply with the design requirements of various power tongs (that are already in use). Hence the backup wrench design may be even more efficient.

[0042] In an embodiment of the first aspect in accordance with the present invention, the measuring means comprises an actuation element, and an actuation element housing with an actuation element housing support surface, and the wrench body comprises a wrench body support wall with a wrench body support wall surface, wherein at least 85% of the, in particular the entire, actuation element housing support surface is covered by the wrench body support wall surface. In particular, the actuation element housing support surface is in contact with the wrench body support wall surface.

[0043] In an embodiment of the first aspect in accordance with the present invention, the backup wrench comprises a support wall, the support wall comprising a measuring means support wall portion with a measuring means support wall portion thickness, and a wrench head jaw support wall portion with a wrench head jaw support wall portion thickness, wherein the measuring means support wall portion thickness is greater than the wrench head jaw support wall portion thickness. The measuring means support wall portion thickness may be measured at the measuring means, in particular at the actuation element of the

[0044] 17051835.JCP2.JCP2 measuring means, in a direction perpendicular to the sucker rod rotation axis and perpendicular to the longitudinal axis of the backup wrench. The wrench head jaw support wall portion thickness may be measured in a plane containing the sucker rod rotation axis which plane is perpendicular to the longitudinal axis of the backup wrench. In particular, the wrench head jaw support wall portion thickness should be measured in a plane perpendicular to the sucker rod rotation axis which plane extends through the wrench head jaw.

[0045] An advantage of the above embodiments is, that the backup wrench can be used to measure higher torques. In particular, the backup wrench may be relatively robust, as the measuring means may be located in a sturdy part of the backup wrench.

[0046] In an embodiment of the first aspect in accordance with the present invention, the measuring means further comprises a communication means. In particular, the communication means comprises a communication line. The communication line may comprise a cable with, for instance, an electrically conductive material or glass fibre.

[0047] Embodiments having communication means configured for wired communication with a processing unit allow for the processing of measurement data, wherein the power source for providing power to the measuring means, and / or processing unit is located at a distance from the hydrocarbon well. Apart from the fact that the construction of the measuring means of the backup wrench remains relatively simple, a safer environment at the hydrocarbon well can be provided. In particular, the backup wrench can be free from a battery that could cause a fire hazard at the hydrocarbon well.

[0048] In an embodiment of the first aspect in accordance with the present invention, the wrench head jaw is releasable from the backup wrench.

[0049] In an embodiment in accordance with the first aspect of the present invention, the measuring means comprises a strain gauge, or an array of strain gauges. The strain gauge(s) may comprise a grid with a strain sensitive grid length direction, and a strain insensitive grid width direction. Preferably, the strain sensitive grid length direction is aligned with the torque application direction. The strain gauge may comprise a Wheatstone bridge, comprising an electric input, and an electric output, wherein, during operation, a

[0050] 17051835.JCP2.JCP2 torque indicator may be taken based on a difference in electrical pressure between input and output.

[0051] In an embodiment of the first aspect in accordance with the present invention, the wrench head jaw comprises a wrench head jaw profile having two (parallel) sucker rod engagement surfaces. The sucker rod engagement surfaces may define a wrench head jaw opening for receiving the non-circular portion of the sucker rod, wherein, after receiving the non-circular portion, rotational movement of the sucker rod with respect to the backup wrench is limited. In particular, the sucker rod engagement surfaces may contact the wrench flats of the non-circular portion of a sucker rod. An advantage of this embodiment is that the wrench head jaw can engage a sucker rod from a lateral side of the sucker rod.

[0052] It should be appreciated, that the sucker rod engagement surfaces are not necessarily parallel to each other. The surfaces could be non-parallel with respect to each other. It is merely important that the surfaces are adapted to engage the non-circular portion of a sucker rod, wherein during engagement rotational movement of the sucker rod is limited by the backup wrench. For example, the sucker rod engagement surfaces could be aligned with a portion of a sucker rod having a triangular shaped cross section.

[0053] In a second aspect in accordance with the present invention, there is provided a backup wrench assembly, the backup wrench assembly comprising a backup wrench in accordance with the first aspect in accordance with the present invention. In particular, the backup wrench assembly may comprise backup wrench for a power tong, comprising: a wrench head jaw, a wrench body, and measuring means for measuring torque, wherein:

[0054] - the wrench head jaw is pivotable with respect to the wrench body, and

[0055] - the measuring means is actuatable upon pivoting the wrench head jaw with respect to the wrench body.

[0056] In an embodiment of the second aspect in accordance with the present invention, the backup wrench assembly, the backup wrench comprises a releasable wrench head jaw, and the backup wrench assembly comprises a releasable further wrench head jaw. The

[0057] 17051835.JCP2.JCP2 further wrench head jaw may be configured for engaging the non-circular portion of a sucker rod of a different size than the wrench head jaw.

[0058] An advantage of embodiments employing a further wrench head jaw is, that efficiency can be further increased, and that complexity can be further reduced. In particular, a single backup wrench can be used for various sucker rod sizes, wherein an operator can easily select a wrench head jaw to make the backup wrench suitable for a particular sucker rod size. In this regard it should be appreciated that a backup wrench comprising measuring means may be relatively expensive as compared to a conventional backup wrench. By providing a backup wrench assembly with one or more inserts, one may require fewer wrenches, and fewer certifications. The present invention may thus provide a cost efficient and easy to use solution for a wrench including measuring means.

[0059] In an embodiment of the second aspect in accordance with the present invention, the further wrench head jaw comprises a further actuation arm arranged to actuate the measuring means. In particular, the further wrench head jaw comprises a further wrench head jaw body defining a further sucker rod rotation axis position, and the further actuation arm extends from a further actuation arm first end adjoining the further wrench head jaw body to a further actuation arm second end. Preferably, the further sucker rod rotation axis is, when the further wrench head jaw is mounted in the backup wrench, located at the same sucker rod rotation position as the sucker rod rotation axis of the (other) wrench head jaw when the wrench head jaw is mounted in the backup wrench. The further wrench head jaw body may be integrally formed with the further actuation arm.

[0060] In an embodiment of the second aspect in accordance with the present invention, the further actuation arm comprises a further actuation arm contact face for contacting the measuring means, in particular the actuation element of the measuring means.

[0061] In an embodiment of the second aspect in accordance with the present invention, the further actuation arm contact face is flush to a plane containing the further sucker rod rotation axis. In such embodiment, the measuring means may comprise an actuation element with an actuation element contact face for contacting the further actuation arm contact face. In particular, the actuation element contact face is also flush to the plane containing the sucker rod rotation axis.

[0062] 17051835.JCP2.JCP2 In an embodiment of the second aspect in accordance with the present invention: the wrench head jaw defines a sucker rod rotation axis for positioning the longitudinal axis of a first sucker rod, the further wrench head jaw defines a further sucker rod rotation axis for positioning the longitudinal axis of a further sucker rod.

[0063] In an embodiment of the second aspect in accordance with the present invention: the wrench head jaw is dimensioned to receive a first sucker rod of a first size with the longitudinal axis of the first sucker rod at the sucker rod rotation axis, and the further wrench head jaw is dimensioned to receive a further sucker rod of a further size with the longitudinal axis of the further sucker rod at the further sucker rod rotation axis. The further size may be different from the first size.

[0064] It should be appreciated, that the wrench head jaw and the further wrench head jaw may define a sucker rod rotation axis position and a further sucker rod rotation axis position, respectively, wherein, when the wrench head jaw engages the first sucker rod, the longitudinal axis of the first sucker rods is positioned at the sucker rod rotation axis position, and wherein, when the further wrench head jaw engages the further sucker rod, the longitudinal axis of the further sucker rod is positioned at the further sucker rod rotation axis position. Preferably, wrench head jaw and the further wrench head jaw are dimensioned such, that, when the wrench head jaw is arranged in the backup wrench, the sucker rod rotation axis position is positioned with respect to the measuring means at a sucker rod rotation axis distance, and, when the further wrench head jaw is arranged in the backup wrench, the further sucker rod rotation axis position is positioned with respect to the measuring means at a further sucker rod rotation axis distance, wherein the sucker rod rotation axis distance and the further sucker rod rotation axis distance are the same.

[0065] In an embodiment of the second aspect in accordance with the present invention, the wrench head jaw and the further wrench head jaw further comprise: a (further) wrench head jaw opening having a (further) wrench head jaw opening size for receiving a (further) sucker rod, and a (further) sucker rod positioning surface for positioning a sucker rod received in the (further) wrench head jaw opening, wherein each wrench head jaw complies with:

[0066] (1) A = T - -2B,

[0067] 17051835.JCP2.JCP2 wherein A is the longitudinal distance, in particular along a (further) longitudinal wrench head jaw axis, from the (further) sucker rod positioning surface up to the (further) actuation arm contact face, B is the (further) wrench head jaw opening size, and T is the longitudinal distance, along the (further) longitudinal wrench head jaw axis, from the (further) actuation arm contact face up to the (further) sucker rod rotation axis. In particular, the actuation arm contact face of the wrench head jaw and the further actuation arm contact face of the further wrench head jaw cover the measuring means, in particular the actuation element end face of the actuation element, when the wrench head jaw is arranged in the wrench head. More in particular, the actuation element extends along an actuation element axis, wherein the actuation arm contact face covers the actuation element axis when the wrench head jaw is arranged in the wrench head. As such, the distance T may be the longitudinal distance from the actuation element axis to the (further) sucker rod rotation axis.

[0068] It should be appreciated, that the above equation (1 ) takes into account sucker rods with a non-circular portion whereat the sucker rod has a square-shaped cross section. If the cross section of a sucker rod at the non-circular portion location is non-square (e.g. rectangular) the wrench head jaw may comply with:

[0069] (2) A = T — ^B + x, wherein % is a correction factor depending on the cross sectional shape of the sucker rod at the non-circular portion. The distance x is measured in a cross sectional plane perpendicular to the longitudinal sucker rod axis. Distance x may be retrieved from a database comprising specific sucker rod specifications.

[0070] In an embodiment of the second aspect in accordance with the present invention, backup wrench assembly comprises: a processing unit for processing measurement data of the measuring means, and communication means, wherein the communication means is suitable for communicatively connecting the measuring means to the processing unit.

[0071] In an embodiment of the second aspect in accordance with the present invention, the backup wrench assembly further comprises: a control unit for controlling torque applied by a power tong based on measurement data processed by the processing unit.

[0072] 17051835.JCP2.JCP2 In a third aspect in accordance with the present invention, there is provided a method of assembling a backup wrench with a power tong, comprising the step of: providing a backup wrench in accordance with the first aspect of the present invention, and mounting the backup wrench to a power tong.

[0073] In an embodiment of the third aspect in accordance with the present invention, the method comprises the step of: connecting the measuring means to a processing unit.

[0074] In an embodiment of the third aspect in accordance with the present invention, the method comprises the steps of: connecting the processing unit to a control unit, and connecting the control unit to the torque application system of a power tong.

[0075] An advantage of embodiments of the third aspect of the present invention is that a conventional power tong can easily be improved to allow the measuring of torque and / or the controlling of the power tong based on torque measurements. In particular, the backup wrench measures the torque received at the lower sucker rod (as opposed to measuring torque applied to the upper sucker rod). This way, more accurate torque reading may be provided.

[0076] In a fourth aspect in accordance with the present invention there is provided the use of a backup wrench, comprising the steps of: providing a backup wrench in accordance with the first aspect in accordance with the present invention, and measuring, by means of measuring means, a torque.

[0077] In an embodiment of the fourth aspect the use further comprises the steps of:

[0078] - processing, by means of a processing unit, measurement data of the measuring means, and / or

[0079] - controlling, by means of a control unit, the torque applied by the power tong based on measurement data processed by the processing unit.

[0080] 17051835.JCP2.JCP2 It should be clear that the third and fourth aspect of the present invention may comprise a backup wrench in accordance with any embodiment of the first aspect, or a backup wrench assembly in accordance with any embodiment of the second aspect, of the present invention.

[0081] Moreover, embodiments of the second, third, and fourth, aspect in accordance with the present invention may include features relating to the first aspect of any combination of the above-described embodiments of the first aspect.

[0082] Advantages of the present invention in respect to the first aspect may also be applicable to the second, third, and fourth, aspect in accordance with the present invention.

[0083] For a better understanding of the present invention, and to show how the same may be put into effect, reference will now be made, by way of example only, to the accompanying drawings in which:

[0084] Figure 1 shows a perspective view of a backup wrench in accordance with the present invention engaging the non-circular portion of a sucker rod;

[0085] Figure 2 shows in perspective view the backup wrench of Figure 1 without the sucker rod;

[0086] Figure 3 shows in another perspective view the backup wrench of Figure 2;

[0087] Figure 4 shows a top view of the backup wrench of Figure 2;

[0088] Figure 5 shows in perspective view the backup wrench of Figure 2 wherein the wrench head jaw is removed;

[0089] Figure 6 shows in perspective view measuring means as included in the backup wrench of Figure 5;

[0090] Figure 7 shows a schematic side view of the measuring means of Figures 5 & 6;

[0091] Figure 8 shows a further perspective view of the backup wrench of Figure 5 wherein the measuring means has been removed;

[0092] Figures 9 & 10 show in perspective view the wrench head jaw as included in the backup wrench of Figures 1 to 4;

[0093] Figure 11 shows a top view of the wrench head jaw of Figures 9 & 10;

[0094] Figure 12 shows a top view of a further wrench head jaw for use in a backup wrench assembly in accordance with the present invention;

[0095] 17051835.JCP2.JCP2 Figure 13 shows a backup wrench assembly in accordance with the present invention; and

[0096] Figure 14 shows a top view of a second embodiment of a backup wrench in accordance with the present invention.

[0097] Figure 1 shows a backup wrench 1 in accordance with the present invention, wherein the backup wrench 1 engages the non-circular portion 2 of a lower sucker rod 3. Figure 2 shows the backup wrench 1 without the lower sucker rod 3.

[0098] The backup wrench 1 comprises a wrench head 4, a wrench body 5, a mounting member 6, measuring means 7, a wrench head jaw 8, and a stop shoulder 9.

[0099] The backup wrench 1 extends, along a backup wrench longitudinal axis 10, from a first longitudinal end 11 to a second longitudinal end 12 located opposite to the first longitudinal end 11 , wherein wrench head 4 is provided at the first longitudinal end 11 and the mounting member 6 is located at the second longitudinal end 12. The wrench body 5 is located between the wrench head 4 and the mounting member 6.

[0100] The wrench head 4 is integrally formed with the wrench body 5 and the mounting member 6. As such, the wrench head 4, the wrench body 5 and the mounting member 6 are together formed of a single piece of material, in particular cast iron.

[0101] The backup wrench 1 comprises a housing 15 in which the wrench head jaw 8 and the measuring means 7 are provided. The housing 15 comprises a first housing part 16 housing the wrench head jaw 8, and a second housing part 17 housing the measuring means 7. The first housing part 16 has a shape corresponding with the exterior of the wrench head jaw 8, wherein the wrench head jaw 8 is rotatable with respect to the wrench head 4. In particular, the wrench head jaw 8 defines a sucker rod rotation axis position 18, and a sucker rod rotation axis 19 extending through the sucker rod rotation axis position 18. When the wrench head jaw 8 engages the sucker rod 3, the (central) longitudinal axis 20 of the sucker rod 3 is aligned with the sucker rod rotation axis 19. The wrench head jaw 8 is rotatable with respect to the wrench head 4 about the sucker rod rotation axis 19 extending through the sucker rod rotation axis position 18. When the wrench head jaw 8 engages a sucker rod 3, the sucker rod rotation axis 19 is the same as the longitudinal axis 20 of the sucker rod.

[0102] 17051835.JCP2.JCP2 The wrench head jaw 8 is releasable from the wrench head 4. In particular, the wrench head jaw 8 is form-fit in the wrench head 4, wherein the wrench head jaw 8 is rotatable, or pivotable, about the sucker rod rotation axis 19 with respect to the wrench body 5 to actuate the measuring means 7. The wrench head jaw 8 is in a direction 21 along the sucker rod rotation axis 19 limited by a bolt 23 and a protective cap 24 (see Figure 13). By removing the bolt 23 (and the protective cap 24) the wrench head jaw 8 may be removed from the wrench head 4.

[0103] As can be seen in Figure 5, the housing 15 comprises a side wall 29 with an internal side wall surface 25 and an internal guide surface 26 which surfaces form physical boundaries for the wrench head jaw 8. In the internal guide surface 26 there is provided a circular groove 27 with a circumferential edge 28. The circular groove 27 is centered around the sucker rod rotation axis 19.

[0104] The measuring means 7 is located at a longitudinal distance 30, along the longitudinal axis 10 of the backup wrench 1 , from the sucker rod rotation axis 19, wherein the measuring means 7 are configured to measure torque upon rotation in a first rotation direction 31 of the wrench head jaw 8 with respect to the measuring means 7.

[0105] The measuring means 7 is provided in the second housing part 17 of the housing 15. The second housing part 17 comprises a sunk surface 32 with respect to the internal guide surface 26 of the first housing part 16. As such, the measuring means 7 is in a direction 33 along the sucker rod rotation axis 19 in part located further in the wrench body 5 than the wrench head jaw 8. The actuation element housing 34 of the measuring means 7 extends entirely within the boundaries of the housing 15 of the wrench body 5. As such, the internal side wall surface 25 of the housing 15 covers the entire actuation element housing support surface 35 of the actuation element housing 34 of the measuring means 7. This way, the backup wrench 1 may be relatively compact. Further, the backup wrench 1 may be more robust.

[0106] The second housing part 17 and therewith the measuring means 7 extends in longitudinal direction 37 along the backup wrench longitudinal axis 10 further from the sucker rod rotation axis 19 than the wrench head jaw 8. With reference to Figure 3 and 6, showing in perspective view the backup wrench 1 and the measuring means 7, the measuring means

[0107] 17051835.JCP2.JCP2 7 is mounted to the wrench body 5 by means of three bolts 38a, 38b, 38c. The bolts extend through three respective bores 39a, 39b, 39c provided in the side wall 29 of the housing 15.

[0108] The measuring means 7 comprises an actuation element 43 in the form of a pin 44, and an actuation element housing 34. The actuation element housing 34 is mounted to the wrench body 5 by means of the three bolts 38a, 38b, 38c. The measuring means 7 further comprises a communication means 45, in the form of a communication line 46. The communication line 46 extends from the housing 15 through a bore 49 from the housing 15 to a bottom surface 47 of the wrench body 5 and away from the wrench body 5. The communication line 46 may be connected to user equipment 48.

[0109] The actuation element 43 is cylindrical, wherein the actuation element 43 extends along an actuation element axis 50 from an actuation element first end 51 with an actuation element end face 52 to an actuation element second end (not shown) inside the actuation element housing 34. The actuation element axis 50 extends in tangential direction 54 with respect to the sucker rod rotation axis 19. The actuation element housing 34 comprises an actuation element housing end face 53. The actuation element end face 52 and the actuation element housing end face 53 are parallel to each other. Movement of the actuation element 43 along the actuation element axis 50 with respect to the actuation element housing 34 generates an electrical signal that is communicated from the measuring means 7 through the communication line 46 to user equipment 48. The electrical signal changes in proportion to the movement of the actuation element 43 with respect to the actuation element housing 34. As can be seen in Figure 4, which provides a top view of the backup wrench 1 , including the measuring means 7 and wrench head jaw 8, the actuation element end face 52 extends in a plane 55 that contains the sucker rod rotation axis 19.

[0110] The mounting member 6 is suitable for mounting the backup wrench 1 to a backup wrench mount 59 of a power tong 56. To this end, the mounting member 6 comprises a through hole 57 for receiving a mounting part 68, in particular a pin, of the power tong 56. The through hole 57 extends along a through hole axis 58. The through hole axis 58 extends in a direction 54 perpendicular to the longitudinal axis 10 of the backup wrench 1 and perpendicular to the sucker rod rotation axis 19.

[0111] 17051835.JCP2.JCP2 Turning to the wrench head jaw 8 of the present invention. The wrench head jaw 8 comprises a wrench head jaw body 60 and a wrench head jaw actuation arm 61 . The wrench head jaw body 60, that has a circular exterior surface 62 corresponding to the circular envelope of the internal side wall surface 63 of the first housing part 16 of the housing 15, defines the sucker rod rotation axis 19. In particular, the wrench head jaw body 60 comprises a wrench head jaw profile 64 with sucker rod engagement surfaces 65, 66, and a sucker rod positioning surface 67, for engaging the wrench flats 93 of the noncircular portion 2 of a sucker rod 3, wherein the sucker rod engagement surfaces 65, 66, and the sucker rod positioning surface 67, are dimensioned to position the sucker rod 3 with its longitudinal axis 20 at the sucker rod rotation axis position 18. Further, and with reference to Figure 10, the wrench head jaw body 60 comprises at a bottom surface 69 thereof a protrusion 71 extending from the bottom surface 69 and having a circular outer edge 70. The envelope of the circular outer edge 70 corresponds to that of the circumferential edge 28 of the circular groove 27 provided in the internal guide surface 26 of the housing 15.

[0112] The wrench head jaw actuation arm 61 actuates the measuring means 7, in particular the actuation element 43 of the measuring means 7, upon rotation of the wrench head jaw 8 in the make-up direction 31 . The wrench head jaw actuation arm 61 extends from an actuation arm first end 72 that adjoins the wrench head jaw body 60 to an actuation arm second end 73. The actuation arm 61 comprises, at the actuation arm second end 73, an actuation arm contact face 74. The actuation arm contact face 74 is configured to contact the actuation element 43, in particular the actuation element end face 52, of the measuring means 7. The actuation arm contact face 74 extends in the plane 55 containing the sucker rod rotation axis 19.

[0113] Figures 11 and 12 show in top view a wrench head jaw 8 and a further wrench head jaw 8’. The further wrench head jaw 8’ has similar features as the wrench head jaw 8. In particular, the further wrench head jaw 8’ comprises a wrench head jaw body 60’ and a further wrench head jaw actuation arm 61 ’. The further wrench head jaw body 60’, that has a circular exterior surface 62’ corresponding to the envelope of the internal side wall surface 63 of the first housing part 16 of the housing 15, defines the sucker rod rotation axis 19. In particular, the further wrench head jaw body 60’ comprises a wrench head jaw profile 64’ with further sucker rod engagement surfaces 65’, 66’, and a further sucker rod positioning surface 67’, for engaging the surfaces of the non-circular portion 2 of a sucker rod 3, wherein the further

[0114] 17051835.JCP2.JCP2 sucker rod engagement surfaces 65’, 66’, and the further sucker rod positioning surface 67’, are dimensioned to position the sucker rod 3 with its longitudinal axis 20 at the sucker rod rotation axis position 18. The further wrench head jaw body 60’ comprises a further bottom surface thereof a further protrusion extending from the further bottom surface that is the same as the bottom surface and the protrusion of the wrench head jaw 8. The further protrusion also has a further circular outer edge (not shown). The envelope of the further circular outer edge corresponds to that of the circumferential edge 28 of the circular groove 27 provided in the internal guide surface 26 of the housing 15.

[0115] The further wrench head jaw actuation arm 61 ’ actuates the measuring means 7, in particular the actuation element 43 of the measuring means 7, upon rotation of the further wrench head jaw 8’ in the make-up direction 31 . The further wrench head jaw actuation arm 61 ’ extends from a further actuation arm first end 72’ that adjoins the further wrench head jaw body 60’ to a further actuation arm second end 73’. The further actuation arm 61 ’ comprises, at the further actuation arm second end 73’, a further actuation arm contact face 74’. The further actuation arm contact face 74’ is configured to contact the actuation element 43, in particular the actuation element end face 52, of the measuring means 7. The further actuation arm contact face 74’ extends in the plane 55 containing the sucker rod rotation axis 19.

[0116] As can be seen in Figures 11 and 12, the wrench head jaws 8, 8’ comprise a positioning part 77, 77’. The positioning part 77, 77’ is designed to position the longitudinal axis 20 of an engaged sucker rod 3 at the sucker rod rotation axis position 18 of the wrench head jaw 8, 8’. The positioning part 77, 77’ extends from a positioning part surface 78, 78’ to a sucker rod positioning part surface 79, 79’. In the shown embodiments, the positioning part

[0117] 77, 77’ includes part of the wrench head jaw body 60, 60’ and the wrench head jaw actuation arm 61 , 61 ’. When arranged in the wrench head 4, the positioning part surface

[0118] 78, 78’ contacts an axial contact surface 83 of the housing 15.

[0119] The positioning part 77, 77’ comprises the wrench head jaw actuation arm 61 , 6T with the actuation arm contact face 74, 74’, wherein the actuation arm contact face 74, 74’ starts at a distance A from the sucker rod positioning surface 67, 67’. When arranged in the wrench head 4, the actuation arm contact face 74, 74’ covers the measuring means 7, in particular the actuation element 43 thereof. More in particular, the actuation arm contact face 74, 74’ covers the measuring means 7 at the actuation element axis 50. The distance A is

[0120] 17051835.JCP2.JCP2 measured in longitudinal direction 81 , 81 ’ along a longitudinal wrench head jaw axis 82, 82’ between the actuation arm contact face 74, 74’ and the sucker rod positioning part surface 79, 79’.

[0121] The longitudinal extent A may be determined based on a given wrench head jaw opening size B, and on a given distance T, wherein distance T is the longitudinal distance between the actuation arm contact face 74, 74’ and the rotation axis position 18. Hence, distance T may be determined with respect to the wrench head 4.

[0122] When comparing the wrench head jaw 8 of Figure 11 with the further wrench head jaw 8’ of Figure 12, it can be seen that the wrench head jaw 8’ of Figure 12 has a smaller opening size B, than the wrench head jaw 8 of Figure 11 . The distance T is the same for both wrench head jaws 8, 8’. The wrench head jaw 8’ of Figure 12 has a positioning part 77’ that has a greater distance A from the actuation arm contact face 74’ to the sucker rod positioning surface 67’ than the positioning part 77 of the wrench head jaw 8 of Figure 11 . Accordingly, it can be made sure that the longitudinal axis 20 of a sucker rod 3 engaged by the wrench head jaw 8 of Figure 11 is positioned at a distance T from measuring means 7, and that the longitudinal rotation axis 20 of a sucker rod 3’ engaged by the further wrench head jaw 8’ of Figure 12 is positioned at the same distance T from the measuring means 7. This way, a fixed distance between a sucker rod 3, 3’ engaged by the wrench head 4 and the measuring means 7 can be maintained for various sucker rod sizes.

[0123] The opening size B of the wrench head jaw 8 of Figure 11 is the same as the size 84 of the non-circular portion 2 of the sucker rod 3 provided in the wrench head jaw 8 of Figure 11 . The opening size B, of the wrench head jaw 8’ of Figure 12 is the same as the size 85 of the non-circular portion 2’ of the sucker rod 3’ provided in the further wrench head jaw 8’ of Figure 12. The size 84, 85 of the non-circular portion 2, 2’ may be measured in a cross section plane perpendicular to the longitudinal axis 20 of a sucker rod 3, 3’.

[0124] The stop shoulder 9 extends from the wrench body 5 between the wrench head 4 and the mounting member 6 in a direction 87 perpendicular to the longitudinal axis 10 of the backup wrench 1 and perpendicular to the sucker rod rotation axis 19 (see Figure 4). The stop shoulder 9 has a stop shoulder surface 88 that is located in direction 87 further than any other part of the backup wrench 1 .

[0125] 17051835.JCP2.JCP2 Figure 13 shows a schematic representation of an embodiment of a backup wrench assembly 100 in accordance with the present invention, which comprises a backup wrench 1 including a wrench head jaw 8 as shown in Figure 1 . Figure 13 further shows a power tong 56, two sucker rods 3, 3’, and a coupling 90.

[0126] The power tong 56 holds 91 an upper sucker rod 3’ of the two sucker rods 3, 3’ at its wrench flats 93 by means of rotatable power tong jaws (not shown). The backup wrench 1 is mounted 106 to the backup wrench mount 59 of the power tong 56 at the mounting member 6 via a mechanical connection as described above. The wrench head 4 with the wrench head jaw 8 holds 94 a lower sucker rod 3 of the two sucker rods 3, 3’ in place, wherein rotational movement of the lower sucker rod 3 about the rotation axis 19, 20 is limited by the backup wrench 1 . In many cases, the lower sucker rod 3 and the coupling 90 are already connected to a string of sucker rods during the make-up process.

[0127] The backup wrench assembly 100 further comprises a communication means 45 that is communicatively connected, on the one hand, to the measuring means 7, and, on the other hand, to a processing unit 94. To this end, the communication means 45 comprises a communication line 46, in particular an electrical cable. The communication line 46 is configured for transferring an electrical signal. In particular, an electrical input signal is transferred via the communication line 46 to the measuring means 7, and an electrical output signal is transferred via the communication line 46 from the measuring means 7 to the processing unit 94.

[0128] The processing unit 94 is comprised by user equipment 48 in the form of a laptop. Alternatively, user equipment 48 may be a tablet, a desktop computer, a smartphone, portable torque reader, etc.

[0129] The processing unit 94 is configured for processing measurement data, in particular an electrical output signal, from the measuring means 7. In particular, the measuring means 7 comprises an electrical input and an electrical output, wherein a torque indicator, in this case a relative movement of the actuation element 43 with respect to the actuation element housing 34 causes a change in electrical resistance at the measuring means 7. The processing unit 94 is arranged to process the measurement data of the measuring means 7, wherein the electrical input signal, which may relate to an electric pressure, is compared to the electrical output signal, which may also relate to an electric pressure. The difference

[0130] 17051835.JCP2.JCP2 between input and output is then, based on an algorithm, translated to an amount of torque. For determining the amount of torque, the distance 30 between the measuring means 7, in particular the actuation element 43 of the measuring means 7, and the rotation axis position 18 is taken into account. Preferably, measurements are time stamped, wherein the time stamped measurement data is stored in a storage unit 95. The storage unit 95 is provided at the user equipment 48.

[0131] In certain embodiments, the processing unit 94 is configured to compare the processed measurement data with threshold torque values. In particular, the processing unit 94 is configured for comparing the determined torque value with a lower bound and an upper bound of a threshold torque value range. If the lower or upper bound of the threshold torque value range is surpassed, the processing unit 94 may provide a signal.

[0132] The processing unit 94 may further be connected to a database 96. The database 96 is comprised by the user equipment 48. The database 96 comprises specific sucker rod information, such as a minimum and maximum threshold torque value required for making up specific sucker rods, sucker rod outer diameter, and the above mentioned correction factor x.

[0133] The assembly 100 further comprises a control unit 98. The control unit is provided at the user equipment 48. The control unit 98 is communicatively connected by means of a communication line 99 to a torque application system 101 of the power tong 56, wherein the control unit 98 is configured to control the torque applied by the power tong 56.

[0134] The user equipment 48 comprises an interface (e.g. screen) 102 for presenting to an operator an amount of torque received at the backup wrench 1 .

[0135] The backup wrench assembly 100 further comprises a user system 103. The user system 103 is arranged at a distance from the user equipment 48, wherein the user equipment 48 and the user system 103 are connected with each other via a wireless communication line 104. The user equipment 48 and the user system 103 communicate with each other via a cellular network. Preferably, the user system 103 comprises a second processing unit 105, wherein the second processing unit 105 is configured for receiving time stamped torque measurement data from the user equipment 48, and for plotting the time stamped torque

[0136] 17051835.JCP2.JCP2 data on a screen at the user system 103. The user system 103 may comprise the database 96.

[0137] In use, the power tong 56 applies a torque to the upper sucker rod 3’, which torque causes the upper sucker rod 3’ to rotate with respect to the coupling 90 and the lower sucker rod 3. As the make-up process proceeds, torque applied by the power tong 56 is transferred via the coupling 90 and the lower sucker rod 3 to the backup wrench 1 . The measuring means 7 measure the torque received at the backup wrench 1 , wherein the measurements are communicated via the communication cable 46 to the user equipment 48. Here, the processing unit 94 of the user equipment 48 processes the measurement data, wherein the measurement data is translated into a certain amount of torque. The torque measurements are presented via the laptop screen 102 to the power tong operator. If the torque received at the backup wrench 1 increases to above the upper threshold value, the control unit 98 instructs the torque application system 101 of the power tong 56 to reduce the amount of torque applied by the jaws of the power tong 56. When an amount of torque has been applied that corresponds with the specifications of the particular sucker rods 3, 3’, the connection between the sucker rods has been made up, and the make-up process may be terminated.

[0138] Figure 14 shows a top view of a second embodiment of a backup wrench in accordance with the present invention. As can be seen, the backup wrench 1 comprises a wrench head jaw 8 engaging a sucker rod 3, a wrench body 5, and measuring means 7, wherein the wrench head jaw 8 is pivotably arranged with respect to the wrench body 5, and wherein pivoting of the wrench head jaw 8 with respect to the wrench body 5 causes the measuring means 7 to be actuated. A mounting part 68 in the form of a pin extends through the mounting member 6 of the backup wrench 1 .

[0139] Different from the embodiment shown in Figure 1 , in Figure 14 the wrench head jaw 8 is connected to the wrench body 5 by means of a pivot 108 which pivot 108 is located at a distance from the sucker rod rotation axis 19. In particular, the wrench head jaw 8 comprises a wrench head jaw pivot part 109 with a wrench head jaw pivot part through hole 110 and the wrench body 5 comprises a wrench body pivot part 111 with a wrench body pivot part through hole 112. A pivot pin 115 extending along a pivot pin axis 113 extends through both the wrench head jaw pivot part through hole 110 and the wrench body pivot part through hole 112. The pivot pin axis 113 is parallel to the sucker rod rotation axis 19.

[0140] 17051835.JCP2.JCP2 Accordingly, in the second embodiment a pivoting connection 108 is formed between the wrench head jaw 8 and the wrench body 5, wherein the wrench head jaw 8 is pivotable with respect to the wrench body 5 about an axis 113 that is located at a distance from the sucker rod rotation axis 19. Further, in the embodiment shown in Figure 14, the measuring means 7 extend in the longitudinal direction 37 of the backup wrench 1 . The measuring means 7 comprises two actuation elements 43, 43’, one on either side of the pivot axis 113. As such, it is possible to measure torque in two rotation directions of the sucker rod 3.

[0141] Although in the above-described embodiments the measuring means is configured for measuring torque, during the make-up process, received at a lower sucker rod in a makeup rotation direction, it is envisioned that the measuring means is configured for measuring torque, during the break-out process, received at a lower sucker rod in a break-out rotation direction opposite to the make-up rotation direction. In particular, the measuring means may be provided at the opposite lateral side of the actuation arm of the wrench head jaw. Moreover, it is envisioned that the backup wrench in accordance with the present invention may comprise, in addition to the measuring means for measuring torque applied to a sucker rod in the make-up direction, further measuring means for measuring torque in the opposite break-out direction. In particular, the further measuring means may be located opposite to the measuring means, wherein the actuation arm is located between the measuring means and the further measuring means. In such case, the actuation arm of the wrench head jaw may comprise an actuation arm first contact face for contacting the actuation element of the measuring means when torque is applied in the make-up direction, and an actuation arm second contact face for contacting a further actuation element of the further measuring means when torque is applied in the opposite breakout direction. In such case, it is preferred that either the actuation arm first contact face or the actuation arm second contact face is flush to a plane containing the sucker rod rotation axis.

[0142] As required, detailed embodiments of the present invention have been disclosed in the figures. However, it is to be understood that the disclosed embodiments are merely exemplary, wherein invention can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.

[0143] 17051835.JCP2.JCP2 The terms "a" or "an", as used herein, are defined as one or more than one. The terms multitude or plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and / or having, as used herein, are defined as comprising (i.e., open language, not excluding other elements or steps). Any reference signs in the claims should not be construed as limiting the scope of the claims or the invention.

[0144] It will be apparent to those skilled in the art that various modifications can be made to the shown backup wrench and backup wrench assembly according to the invention without departing from the scope as defined in the claims.

[0145] 17051835.JCP2.JCP2

Claims

CLAIMS1 . Backup wrench for a power tong, comprising: a wrench head jaw, a wrench body, and measuring means for measuring torque, wherein:- the wrench head jaw is pivotable with respect to the wrench body, and- the measuring means is actuatable upon pivoting the wrench head jaw with respect to the wrench body.

2. Backup wrench of claim 1 , wherein the wrench head jaw defines a sucker rod rotation axis for positioning the longitudinal axis of a sucker rod.

3. Backup wrench of claim 2, wherein the wrench head jaw is pivotable with respect to the wrench body about the sucker rod rotation axis.

4. Backup wrench of claim 2 or 3, wherein the measuring means is actuatable in tangential direction with respect to the sucker rod rotation axis.

5. Backup wrench of any previous claim, the wrench head jaw comprising an actuation arm arranged to actuate the measuring means.

6. Backup wrench of any of claims 2 to 4, and claim 5, wherein the actuation arm comprises an actuation arm contact face for contacting the measuring means, wherein the actuation arm contact face is flush to a plane containing the sucker rod rotation axis.

7. Backup wrench of any previous claim, further comprising a mounting member for mounting the backup wrench to a backup wrench mount of a power tong, wherein the measuring means is located away from the mounting member.

8. Backup wrench of any previous claim, wherein the measuring means comprises an actuation element and an actuation element housing, wherein the actuation element is actuatable upon pivoting of the wrench head jaw with respect to the wrench body.17051835.JCP2.JCP29. Backup wrench of claim 8, wherein the actuation element housing comprises an actuation element housing support surface, and the wrench body comprises a wrench body support wall with a wrench body support wall surface, wherein at least 85% of the, in particular the entire, actuation element housing support surface is in contact with the wrench body support wall surface.

10. Backup wrench of any previous claim, the measuring means further comprising communication means.11 . Backup wrench of any previous claim, wherein the wrench head jaw is releasable from the backup wrench.

12. Backup wrench assembly, comprising a backup wrench in accordance with claim 11 , the backup wrench assembly comprising a releasable further wrench head jaw.

13. Backup wrench assembly of claim 12, wherein the further wrench head jaw comprises a further actuation arm with a further actuation arm contact face arranged to actuate the measuring means.

14. Backup wrench assembly of claim 13, comprising a backup wrench in accordance with claim 6, wherein the further actuation arm contact face is flush to the plane containing the sucker rod rotation axis.

15. Backup wrench assembly of any of claims 13 or 14, wherein the wrench head jaw and the further wrench head jaw each comprise: a wrench head jaw opening having a wrench head jaw opening size for receiving a sucker rod, and a sucker rod positioning surface for positioning a sucker rod received in the wrench head jaw opening, wherein each wrench head jaw complies with:(1) A = T - -2B, wherein A is the longitudinal distance from the sucker rod positioning surface up to the actuation arm contact face, B is the wrench head jaw opening size, and T is the longitudinal distance from the actuation arm contact face up to the sucker rod rotation axis.17051835.JCP2.JCP216. Backup wrench assembly, comprising a backup wrench in accordance with any of claims 1 to 11 , the backup wrench assembly comprising: a processing unit for processing measurement data of the measuring means, and communication means, wherein the communication means is suitable for communicatively connecting the measuring means to the processing unit, and optionally a control unit for controlling torque applied by a power tong based on measurement data processed by the processing unit.

17. Method of assembling a backup wrench with a power tong, comprising the steps of: - providing a backup wrench in accordance with any of the claims 1 to 11 , and mounting the backup wrench to a power tong.

18. Use of a backup wrench, comprising the steps of: providing a backup wrench in accordance with any of the claims 1 to 11 , and - measuring, by means of the measuring means, a torque.17051835.JCP2.JCP2

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