NO20150916A1 - Apparatus and method for applying torque to a first tube against a second tube - Google Patents

Description

APPARATUS AND METHOD FOR SUPPLYING TORQUE TO A FIRST PIPE IN RELATION TO A SECOND PIPE

This invention relates to screw pliers and other power pliers.

When constructing oil or gas wells, it is usually necessary to construct long drill pipes. Because of the length of these pipes, sections or lengths of pipe are added to the pipe as it is lowered into the well from a drilling platform. Especially when it is desired to add to a pipe section or pipe length, the string is usually held against falling into the well by applying the retaining wedges in a spider placed in the deck of the drilling platform. The new pipe section or pipe length is then moved from a stand to the well center above the spider. The threaded male part of the pipe section or pipe length to be connected is then placed over the threaded female part of the pipe in the well, and the connection is tightened by rotation between them. A pipe clamp is connected to the top of the new pipe section or pipe length, and the entire pipe string is lifted slightly so that the retaining wedges in the spider can be released. The entire pipe string is then lowered to the top of the section adjacent to the spider, after which the retaining wedges in the spider are again applied, the pipe clamp is disconnected, and the process is repeated.

It is common practice to use a pair of pliers to tighten the connection to a predetermined torque to make this connection. The forceps are placed on the platform, either on rails or suspended by a chain in a tower. To tighten or loosen a threaded connection, an arrangement of two pliers is required. An active tong (or wrench) applies torque to the pipe section above the threaded connection, while a passive tong (or support tong) applies a reaction torque below the threaded connection. The support clamp clamps the pipe below the threaded connection and prevents it from rotating. This clamping can be done mechanically, hydraulically or pneumatically. The vise grips the upper part of the connection and is driven to apply torque over a limited angle.

This power pliers arrangement is also used to pull connections between other pipes, such as casing and production pipes.

To provide high torque, the vise is usually hydraulically driven. One or two hydraulic cylinders drive the tong through a small angle, typically in the region of 25°, depending on the tong design. Due to the geometric design commonly used, the torque performance of the pliers changes as a sine function of the angle over which it is driven, resulting in a reduction in torque performance over the drive angle of up to 15%.

To tighten or loosen a joint of modern drill pipe or casing, high torque must be applied over a large angle. This angle is sometimes six

times greater than what a traditional screwdriver can provide. To overcome this, the pliers must grip and twist the pipe several times to fully tighten or loosen the threaded connection. This has a number of disadvantages. The activity of gripping and releasing the pipe repeatedly can damage the pipe surface. Due to the high costs associated with the construction of oil and gas wells, time is critical, and the repeated clamping and release of the vise greatly increases the time it takes to fasten each new pipe section or pipe length. It also has the effect of making the supplied torque inconsistent, increasing the difficulty of accurately controlling the torque with respect to the angular rotation.

WO 93/18276 describes an apparatus which should apply torque to a first pipe in relation to a second pipe. The apparatus comprises first and second pliers which are to grip the first and the second pipe, respectively.

GB 2128526 describes a tongs to grip a pipe, which tongs are driven by a pinion and gear.

GB 1215967 describes a tool fixed in rotary table holding wedges and pliers for connecting and disconnecting pipes.

US 2566651 describes a tool according to the preamble of claim 1.

According to a first aspect of the present invention, there is provided apparatus for applying torque to a first pipe in relation to a second pipe, wherein the apparatus comprises a first pliers for gripping the first pipe, and a second pliers for gripping the second pipe , wherein the first pinion is provided with teeth around a peripheral surface, and wherein the second pinion is provided with at least one pinion, the pinion engaging the teeth in such a way that the first pinion and the second pinion can be rotated in relation to each other when the pinion is rotated. Between the first tongs and the second tongs, bearings supported on resilient means are provided to support one tong on top of the other

pliers.

The first plier is preferably a support plier, and the second plier is a screw plier. Both tongs are preferably substantially cylindrical, and an axial through passage for receiving tubes is preferably provided. A passage is preferably provided from a peripheral edge to the axial passage in each tong to allow insertion of tubing into the axial passage. The pinion is preferably located at or near the periphery of the second pinion. A motor may be provided on the second pinion and be coupled to the pinion or each pinion.

The second pinion is preferably provided with two pinions, although in another embodiment it may be provided with only one. The pinions are preferably located at or near the periphery of the second pinion with essentially 180° mutual distance around the longitudinal axis of the pinion. In another embodiment, they can be placed with a distance of essentially 120° from each other around the longitudinal axis of the tang.

The first tong preferably comprises a plurality of hydraulically driven clamping jaws to grip the first pipe, and the second tong comprises a plurality of hydraulically driven clamping jaws to grip the second pipe. Each jaw may be equipped with two or more jaws and is preferably attached to the hydraulic drive means via a spherical bearing, although the jaws may be in an integral part of the hydraulic drive means.

The bearings, which are supported on elastic means, facilitate mutual axial movement between the first and second pliers.

Also described is an apparatus for applying torque to a first tube relative to a second tube, which apparatus comprises a gear and at least one pinion and a first clamping device for clamping the first tube inside the gear, where the pinion is attached to a second clamping means which is to clamp the second tube, and the pinion engages with the gear in such a way that the first clamping means and the second clamping means can be rotated relative to each other by rotating the pinion.

The first clamping means preferably comprises jaws mounted inside the gear around an axial passage extending through the gear. The second clamping means preferably comprises jaws mounted inside a clamping housing around an axial passage which extends through it. A motor is preferably attached to the clamping housing and connected to the pinion or each pinion.

According to a second aspect of the present invention, there is provided a method for applying torque to a first pipe in relation to a second pipe, which method comprises: clamping the first pipe in a first pair of pliers; clamping the second tube in a second tongs; and rotating a pinion which is connected to the second pinion and which engages with teeth provided around a peripheral surface of the first pinion to thereby rotate the first pinion relative to the second pinion; and supporting one pincer on top of the second pincer using bearings, supported on resilient means, provided between the first pincer and the second pincer.

Also described is a method for connecting a tool to a length of pipe, which method comprises the steps: securing the tool in a basket; lowering a plier arrangement having a rotatable portion and a stationary portion relative to the basket to engage respective locking members of the plier arrangement and the basket with each other thereby securing the basket and the tool relative to the stationary portion of the plier arrangement; and rotating the length of pipe using the rotatable part of the pliers arrangement to thereby connect the tool to the length of pipe.

This method can be used to connect a tool, such as a drill bit, to a length of drill pipe. The coupling part on the drill pipe length can be brought close to a corresponding coupling part on the tool either before or after lowering the tong arrangement.

The drill string length can be gripped by the rotatable part of the tong arrangement either before or after the lowering of the tong arrangement. The drill string length can be placed close to the basket containing the tool either before or after the string is gripped by the rotatable portion of the tong arrangement.

By performing the steps according to the above fourth aspect of the present invention in reverse order (including rotating the length of pipe in the opposite direction), a tool can be disconnected from a length of pipe.

An apparatus is also described which will make it possible to attach a tool to a length of drill pipe, which apparatus comprises: a basket which is arranged to hold a tool securely; a tong arrangement having a rotatable portion and a stationary portion, the rotatable portion being adapted to grip and rotate the length of pipe in use; and first locking means provided on the basket and second locking means provided on the stationary portion of the tong arrangement, the first and second locking means being engageable with each other to secure the basket relative to the stationary portion of the tong arrangement.

The first and second locking means can preferably be brought into engagement with each other and released from each other by means of linear movement of the pliers arrangement in relation to the curve.

The basket is preferably arranged to prevent rotation of the tool within the basket, while the rotatable portion of the tong arrangement in use can be used to rotate the length of drill pipe to secure a screw connection between the length of drill pipe and the tool.

One of the first and the second locking means preferably comprises one or more slots, and the other of the first and the second locking means comprises one or more projecting elements, where the slots and the elements can be brought into engagement with each other and released from each other by mutual linear movement between the pincer arrangement and the curve.

It further describes a pair of pliers for use when clamping a length of pipe while connecting or unscrewing a connection, which pliers comprise: a body portion having a central opening to receive a length of pipe; and at least two clamping mechanisms mounted on said body, the clamping mechanisms being mutually positioned at a radial distance around said opening; a plurality of elongate fastening elements placed between each of the clamping mechanisms and the body of the pliers, where each fastening element has a flat surface to rest against one side of a clamping mechanism, and a rounded side to be placed in a complementary designed recess in the pliers body, where each to some extent can be displaced from radial alignment in line with the central opening of the pliers.

It will now be described, only as an example, some preferred embodiments of the invention with reference to the accompanying drawings, where: Fig. 1 is an elevation of an arrangement of a screwdriver and a support pliers; Fig. 2 is a side view of the screw pliers and the support pliers in fig. 1; Fig. 3 is an elevation of the support tongs in fig. 1; Fig. 4 is a sectional perspective of the support tongs in fig. 1; Fig. 5 is a sectional perspective of the screwdriver in fig. 1; Fig. 6 is an elevation of the screw pliers and the support pliers in fig. 1 carried by a C-frame and fixed in a frame for handling equipment on tracks at a rigging deck; Fig. 7 is an elevation of the screw pliers and the support pliers in fig. 1 in use, with a tube clamped in the vise; Fig. 8 is an elevational view of an alternative vise and support tong arrangement; Fig. 9 is an elevational view of an arrangement of a further alternative vise and support tong; Fig. 10 illustrates a modified pincer arrangement; Fig. 11 illustrates a modified support tong; Fig. 12 illustrates in detail a clamping arrangement in the pliers of fig. 11 included support elements; Fig. 13 illustrates an arrangement for connecting a drill bit to a length of drill pipe; Fig. 14 illustrates the arrangement in fig. 13 during the pairing operation;

and

Fig. 15 illustrates the arrangement in fig. 13 after the pairing operation

has ended.

Fig. 1 and 2 show an arrangement with a vise-support pliers combination. A vise 1 is generally in the form of a plate with an opening 2 through its center to receive a length of drill pipe (not shown), and a recess 3 cut from the edge to the opening 2 in the middle. The vise 1 is provided with two pinion drives 4 arranged opposite each other at the periphery of the disk, with an equal distance to each side from the recess 3. Each pinion drive comprises a drive motor 5, drive shaft 6 and pinion 7 attached to the drive shaft 6.

A support plier 11 is placed below the screwdriver 1. The support plier generally has the shape of a disk with similar dimensions to the screwdriver 1. The support plier is also provided with an opening 12 through the center and a recess 13 from the edge to the center opening. The opening 12 and the recess 13 correspond to the opening 2 and the recess 3 in the pliers when the support pliers 11 and the pliers 1 are aligned correctly in line with each other.

A plurality of guide rollers 10 or other guide elements are distributed around the edge of the pliers 1 to maintain the alignment of the pliers 1 in line with the support pliers 11.

A gear wheel 14 is provided along the periphery of the support pinion 11, interrupted by the recess 13. The gear wheel 14 engages with the pinions 7 attached to the motors 5 on the pinion, so that when the drive motors 5 drive the drive shafts 6 and the gears 7, the pinion 1 rotates in relation to the pinion 11 The angle of rotation is limited by the recess 13 of the support pliers.

Fig. 3 shows support pliers 11 before the screwdriver is placed on top of it. The support passage 11 has a plurality of roller bearings 21, and the pliers 1 are designed to be placed on top of these. The roller bearings 21 are supported by resilient means such as springs, elastic material or hydraulic/pneumatic cylinders, to support the vise during tightening. During one tightening cycle, the pipe lengths will move axially in relation to each other as the connection is tightened. The pliers must follow the upper pipe length's axial movement during one tightening cycle. The length of this axial movement depends on the pitch of the threads.

Three clamping jaws 8 equipped with jaws 9 are placed inside each of the vises

1 and the support tongs 11. These are operated hydraulically to clamp the length of drill pipe in place in the middle of the tongs. The supply of hydraulic power can be provided via hoses (not shown).

Fig. 4 shows the clamping mechanism of the support pliers 11. Three hydraulic pistons 16, comprising piston rods 17 and

chambers 18, are placed inside the supporting tongs 11 frame. Each piston rod 17 has an end 19 which is attached to the support pin 11's outer edge. At the other end of the piston, the jaw 8 containing two jaws 9 with teeth (not shown) is attached to the chamber 18 via a spherical bearing 20. With the arrangement shown, each length of drill pipe is clamped by three jaws and six jaws at the joint. The spherical bearings 20 enable the jaws and jaws to fit closely to the pipe surfaces, which results in a small penetration depth for the teeth of the jaws into the pipe surface and thus extends the life of the drill pipe. The pliers have a similar clamp in an oblique design, as shown in fig. 5.

Fig. 6 shows the pliers 1 and the support pliers 11 carried by a C-frame 22 for handling on the rig. The C-frame 22 is in turn fixed in a frame 23 which will handle the equipment on tracks on the rig deck. A drill pipe spinner 24 is mounted on the C-frame above the tongs to rotate a length of drill pipe at high speed.

To create a connection between two lengths of drill pipe, align the recesses 3

and 13 in the pliers 1 and the support pliers 11 in line with each other (the pliers may already be in this position after the pliers have been removed from a previous pipe section). Two lengths of drill pipe 25, 26 are then fed into the openings 2, 12 in the vise 1 and the support tong 11, respectively, through the recesses 3, 13, and the lower length of pipe 26 is clamped in place in the support tong 11. The upper length of pipe 25 is fed into the drill pipe

the spinner 24 and is rotated at high speed to pre-attract the threaded connection. The final high torque will be supplied by the pliers 1.

The upper pipe length 25 is now clamped in place in the opening 2 through the pliers 1. The pinion drives 4 are then driven to tighten the connection between the pipe lengths 25, 26 until the connection is fully tightened, or until one of the pinion drives 4 is at the edge of the recess 13, at which stage the screwdriver 1 is at one end of its possible arc of movement in relation to the support pliers 11. The maximum screw angle that can be reached in one cycle in the embodiment shown is +/- 75°. If necessary, the upper pipe length 25 can then be released from the pliers 1, the pliers can be returned to their original position and the tightening process repeated.

To loosen a connection, the above operation is performed in reverse order.

An even greater screw angle can also be easily achieved with this arrangement, as shown in fig. 7. The drill pipe lengths 25, 26 are fed into the tongs 1, 11 through the recesses 3, 13 and pre-tightened using the drill pipe spinner 24 as described above. Before the upper pipe length 25 is clamped in place in the opening 2, however, the screwdriver's drive device is reversed, and the screwdriver 1 is driven to its end position in relation to the support pliers, as shown in fig. 7. The upper pipe length 25 is now clamped firmly with the pliers in this position, so that with the design shown a screw angle of 150° can be achieved. Fig. 8 shows a similar arrangement of a vise-support pliers combination to that described above. In this case, however, only one pinion drive 4 is used, which increases the possible screw angle to 300°. Fig. 9 shows another similar arrangement, where two pinion drives 4 are used as in fig. 1 to 7. This time the pinion drives 4 are not located opposite each other, but are located at a distance of 120° to each side from the recess 3. This gives the advantage of torque and control provided by two drives, but allows a greater screw angle than the arrangement in fig. 1. This design's maximum screw angle will be in the range of 210°.

The torque can be monitored by measuring the reaction torque at each drive device using a load cell, or by measuring the power from the drive motor.

It should be understood that other variations are possible, but still fall within the scope of the invention. For example, the preferred embodiments show an arrangement where the pinion drives are mounted on the collet, and the pinion is mounted on the support collet. However, the arrangement could be reversed, with the pinion drives mounted on the support collet and the large pinion mounted on the collet. Such an arrangement is illustrated in fig. 10.

Alternatively, the vise could be provided with a gear, and the pinion drives be mounted on the frame 24.

Hydraulic clamping cylinders are shown, but the tongs will be able to clamp the lengths of drill pipe by any known means.

The preferred designs show one or two pinion gears, but more could be used if arranged in a suitable design.

Although the preferred embodiments have been described in relation to tightening lengths of drill pipe, it should be understood that the arrangements described are suitable for applying torque to any tubular sections. Fig. 11 illustrates, partially cut through, a modified support tongs 40 which can replace the support tongs 11 in the embodiment of fig. 1 to 9. The modified pliers 40 has only two jaws 41 which are attached to the respective clamping arrangements 42. Each arrangement 42 is held in place within the main body 43 of the pliers 40 by a set of four "pendulum" bolts 44. A clamping arrangement 42 attached to four pendulum bolts 44 are illustrated in more detail in fig. 12, where it can be seen that each bolt comprises a cylinder split in half along its longitudinal axis to provide a flat surface and a rounded surface. The flat surface of each bolt 44 abuts the side of the clamping arrangement 42, while the rounded side is placed in a rounded recess 45 provided in the side of the main body 43 opposite the clamping arrangement. It should be understood that since the bolts 44 are able to rotate within their respective recesses in the pliers body 43, each clamping arrangement 42 can rotate slightly about its center. This allows the jaws 41 to adapt to the outer surface of a pipe to be clamped, when the pipe is not, for example, perfectly cylindrical. Fig. 13 illustrates apparatus that can be used in conjunction with a tong arrangement 49 to connect a tool such as a drill bit to and from a length of pipe such as a drill pipe. The apparatus comprises a basket 50 which, in use, is arranged to be placed on the deck of a drilling rig. The basket 50 has an opening in its top to receive a tool 51 to be connected to a length of pipe 52. The opening has a shape which is complementary to the shape of the tool 51, so that the tool is held securely in an upright position, and rotation of the tool within curve 50 is prevented.

Two opposite sides of an upper plate in the basket 50 are provided with slits 53. The slits 53 are shaped to receive locking members 54 projecting downwardly from the lower surface of the support tongs 55 in the tong arrangement. The operation to connect to a tool will now be described.

As shown in fig. 13, the tool 51 is first placed in the basket 50. The length of pipe 52 is moved to a position above the tool (Fig. 14) and lowered to bring the female coupling of the pipe into engagement with the externally threaded coupling of the tool 51. At this point the tong arrangement is brought forward to the tube 52 with the jaws of the rotary and support tongs fully open, and the tongs are placed around the tube 52. The tong arrangement is then lowered within its frame to a position where the locking elements 54 are received by the respective receiving slots 53 in the basket 50. In this position, the curve is locked to the support clamp. The jaws of the rotary plier are then clamped firmly against the pipe 52, and the rotary plier is rotated in relation to the support plier to tighten the threaded joint (fig. 15). The jaws of the rotary bar are then released, and the tong assembly is withdrawn from around the pipe. The pipe and the connected tool can then be lifted clear of the basket 50.

It should be understood that the tool 51 can be disconnected from the tube 52 by performing the same operation, but in reverse order.

Claims (19)

1. Apparatus for applying torque to a first pipe (26) relative to a second pipe (25), wherein the apparatus comprises a first tongs (11) for gripping the first pipe (26), and a second tongs (1) to grip the second tube (25), where the first pincer (11) is provided with teeth (14) around a peripheral surface, and where the second pincer (1) is provided with at least one pinion (7), the pinion engages with the teeth (14) in such a way that the first pincer (11) and the second pincer (1) can be rotated relative to each other when the pinion (7) is rotated, and characterized in that between the first pincer (11) and the second pincer (1) is provided with bearings (21) which are supported on resilient means, to support one pincer on top of the other pincer. 2. Apparatus as stated in claim 1, where the first pliers (11) are support pliers, and the second pliers (1) are screw pliers. 3. Apparatus as stated in claim 1 or 2, where the pinion or each pinion (7) is located at or near the periphery of the second pinion (1). 4. Apparatus as stated in claim 1, 2 or 3, where the first forceps (11) is essentially cylindrical. 5. Apparatus as set forth in any preceding claim, wherein the second forceps (1) is substantially cylindrical. 6. Apparatus as set forth in any preceding claim, wherein the first (11) and the second tongs (1) each have an axial through passage (12, 2) for receiving a tube (26, 25). 7. Apparatus as set forth in claim 6, wherein a passage (13, 3) is provided from the edge of the axial passage (12, 2) in both the first (11) and the second forceps (1) to allow the introduction of a tube (26, 25) in the axial passage (12, 2) in both the first and the second tongs. 8. Apparatus as set forth in any preceding claim, wherein a motor (5) is provided on the second pinion (1) and is coupled to the pinion or each pinion (7). 9. Apparatus as set forth in any preceding claim, wherein the second pinion (1) is provided with two pinions (7). 10. Apparatus as set forth in claim 9, where the pinions (7) are located at or near the periphery of the second pincer (1) and are placed essentially 180° apart around the longitudinal axis of the pincer. 11. Apparatus as stated in claim 9, where the pinions (7) are located at or near the periphery of the second pincer (1) and are placed with essentially 120° mutual distance around the longitudinal axis of the pincer. 12. Apparatus as set forth in any one of claims 1 to 8, wherein the second pinion (I) is provided with only one pinion (7). 13. Apparatus as set forth in any preceding claim, wherein the first gripper (II) comprises a plurality of hydraulically operated clamping jaws (8) for gripping the first tube (26). 14. Apparatus as set forth in any preceding claim, wherein the second gripper (1) comprises a plurality of hydraulically operated clamping jaws (8) for gripping the second pipe (25). 15. Apparatus as stated in claim 13 or 14, where each jaw (8) is equipped with two or more jaws (9). 16. Apparatus as stated in claim 13, 14 or 15, where each jaw (8) is attached to hydraulic propellant (18) via a spherical bearing (20). 17. Apparatus as stated in claim 13, 14 or 15, where the first tongs (11) and the second tongs (1) each comprise a plurality of hydraulic propellants, where each hydraulic propellant comprises a piston rod (17) and a piston chamber (18) ), and the jaw (8) is an integral part of the hydraulic propellant, where the jaws (9) are placed in pockets in the piston chamber (18). 18. Apparatus as claimed in any preceding claim for assembly of borehole pipe. 19. Method for applying torque to a first pipe (26) in relation to a second pipe (25), where the method comprises: clamping the first pipe in a first tongs (11); clamping the second tube (25) in a second tongs (1); rotation of a pinion (7) which is connected to the second pinion (1) and which engages with teeth (14) provided around a peripheral surface of the first pinion (11), thereby rotating the first pinion relative to the other seaweed; and characterized by supporting one pincer on top of the second pincer using a bearing (21), supported on resilient means, provided between the first pincer (11) and the second pincer (1).