APPARATUS AND METHOD FOR ALIGNING TUBULARS

Abstract: An apparatus for aligning tubulars which apparatus comprises at least one guide (11; 115), a tong (2; 102) and a backup unit (3; 103) wherein said at least one guide (11; 115) is arranged on or between said tong (2; 102) and said backup unit (3; 103), characterised in that said at least one guide (11; 115) is, in use, movable towards and away from a box of a tubular with respect to said backup unit. An apparatus for aligning tubulars which apparatus comprises a tong (2), a backup unit (3), at least one torsion post (4, 5) arranged therebetween, the apparatus further comprising at least one guide (11), characterised in that said at least one guide (11) is mounted on said at least one torsion post (4, 5). A method for aligning tubulars using the apparatus of the invention, comprising the step of moving said at least one guide towards and away from a box of a tubular with respect to said backup unit.

Description: Apparatus and Method for Aligning Tubulars This invention relates to an apparatus and a method for aligning tubulars. During the construction, maintenance and repair of oil and gas wells it is necessary to connect a large number of tubulars, for example lengths of drill pipe or casing. Conventionally the upper end of a tubular is provided with a threaded socket or box whilst the lower end is provided with a threaded pin which is slightly tapered. In practice it is very easy for the pin of one tubular to be incorrectly inserted into the socket of another tubular with the result that the threads on one or both the pin and the socket can readily be damaged. Considerable skill is required to correctly align tubulars and historically this task has been undertaken by a highly experienced rig-hand called a "stabber". In order to facilitate correct alignment a device known as a "stabbing guide" is frequently used. One such stabbing guide comprises a plastic body member which can be mounted on the socket of a pipe held in slips. The plastic body member has a central passageway the upper part of which defines a funnel which leads into a lower passageway which is concentric with the socket. In use, as the upper tubular is lowered, its pin enters the funnel of the stabbing guide and then travels down the lower passageway into the socket. The stabbing guide (which comprises two semi-circular pieces hinged together around the socket) is then removed and the tubulars are screwed together and tightened to the required torque either by a power tong or a tong assembly comprising a power tong and a backup tong. It has been observed that an accuracy in alignment of approximately 1mm is required to inhibit problems associated with thread misalignment. PCT Publication Number WO 98/32948, owned by the applicants for the present application, discloses an apparatus for aligning tubulars which apparatus comprises a guide mounted on one of a power tong and a backup tong. It has been observed that the prior art apparatus, although reasonably accurate, is not sutiable for multiple uses where accuracy is paramount and with little physical input from rig hands. Accordingly, the present invention provides an apparatus for aligning tubulars which apparatus comprises at least one guide, a tong and a backup unit wherein said at least one guide is arranged on or between said tong and said backup unit, characterised in that said at least one guide is, in use, movable towards and away from a box of a tubular with respect to said backup unit. The at least one guide may be shaped to act like a funnel in guiding a pin into a box. The guide is moveable in a substantially radial direction towards and away from the centre of the backup unit. Preferably, the apparatus further comprises a piston and cylinder, wherein the at least one guide is moveable towards and away from a box of a tubular through the operation said piston and cylinder. The piston and cylinder may be activated by pneumatic or preferably, hydraulic fluid. Advantageously, the apparatus further comprises an axle wherein the at least one guide is moveable thereabout. Preferably, the apparatus further comprises a guide holder. Advantageously, the apparatus comprises two guides which are attachable to the guide holder. Preferably, the apparatus further comprises a spring which biases said at least one guide to an open position. Advantageously, the apparatus further comprises at least one torque post wherein said at least one guide is attachable thereto. Preferably, the apparatus further comprises a bracket wherein said at least one guide is moveable with respect to said bracket. Advantageously, said at least one guide is made from an elastomeric material. The invention also provides an apparatus for aligning tubulars which apparatus comprises a tong, a backup unit, at least one torsion post arranged therebetween, the apparatus further comprising at least one guide, characterised in that said at least one guide is mounted on said at least one torsion post. The invention also provides a method for aligning tubulars using the apparatus of the invention, comprising the step of moving said at least one guide towards and away from a box of a tubular with respect to said backup unit. For a better understanding of the present invention reference will now be made, by way of example, to the accompanying drawings, in which:- Figure 1 is a perspective schematic view of a first embodiment of an apparatus of the present invention in a first stage of operation, with parts cut away; Figure 2 is an enlarged perspective schematic view of the apparatus of Figure 1 in a second stage of operation; Figure 3 is an exploded perspective view of part of the apparatus of Figure 1 ; Figure 4 is a side plan view of the apparatus of Figure 1, in the second stage of operation; Figure 5 is a front plan view of the apparatus of Figure 1, in the second stage of operation, with parts cut away and parts shown in cross-section; Figure 6 is a top plan view of the apparatus of Figure 1, in the second stage of operation, with parts cut away; Figure 7 is a perspective schematic view of a second embodiment of an apparatus of the present invention, in a first stage of operation, with parts cut away; Figure 8 is a perspective view of the apparatus of Figure 1 in a second stage of operation, with parts cut away; Figure 9 is a side plan view of the apparatus of Figure 7; Figure 10 is a front plan view of the apparatus of Figure 7; and Figure 11 is a top plan view of the apparatus of Figure 7. Referring to Figures 1 to 7, there is shown an apparatus generally identified by reference numeral 1. The apparatus 1 comprises a power tong 2 and a backup tong 3. Torsion posts 4 and 5 are arranged between the power tong 2 and the backup tong 3 on opposing sides thereof. A guide unit 6 is provided on each of the torsion posts 4 and 5. Referring to Figure 3, each guide unit 6 comprises a clamp 7, a spring 8, a piston and cylinder unit 9, a guide shoe holder 10 and a guide shoe 11. The guide units 6 may be mirror images of each other. The clamp 7 comprises two semi-cylindrical parts 12 and 13 which are bolted together via lugs 14, 15, and 16 and 17. Semi-cylindrical sleeves 18 and 19 lie between the semi-cylindrical parts and the torsion post 4, 5 on which the clamp 7 is mounted. The semi-cylindrical part 13 is provided with upper and lower substantially horizontal lugs 20 and 21. The lugs 20 and 21 are substantially triangular and are provided with stub axles 22 and (not shown) at the apexes. The spring 8 comprises a reel 23 fixed to the upper lug 20 and a sprung wire 24 wrapped around the reel 23. The spring wire 24 has two ends extending from the reel 23 substantially at a tangent thereto. One of the ends is retained in a clamping element 25 which is fixed to the upper lug 20, and the other end contacts, and is biased against a pin 26 arranged on one side of the piston and cylinder unit 9. The piston and cylinder unit 9 comprises a cylinder 27 which has a square neck portion 28 at a front end thereof. Holes 28, 29 are provided in the top centre and bottom centre of the square neck portion 28 for receiving the axle stubs (22 and not shown). The piston and cylinder unit 9 is moveable about stub axles 22 and (not shown) against spring 8. The square neck portion 28 is also provided with posts 30 and (not shown) on opposing sides thereof which are fixed thereto. A block 31 is provided with holes 32 and (not shown) for slideably receiving the posts 30 and (not shown). The block 31 is attached to one end of a piston rod 33 (Figure 5). A piston 34 is attached to the opposing end of the piston rod 33. The piston 34 is slideably arranged in the cylinder 27. The block 31 is connected to a guide shoe holder 10 by bolts 35 and 36. The guide shoe holder 10 comprises a curved face 37 which is provided with reinforcing ribs 38 and 39 which are arranged substantially horizontally and spaced apart vertically. The reinforcing ribs 38 and 39 are provided with holes 40 for receiving bolts 35 and 36. The ends of the guide shoe holder are provided with lugs 41 which facilitate holding of the guide shoe 11. The guide shoe 11 may be formed from an elastomeric material. The guide shoe 11 has a top section 42 which has an inwardly sloping angled portion 43 and a lower lip 44. A bottom section 45 is substantially flat. The top section 42 is arranged above the guide shoe holder 10. Prior to use, a guide unit 6 is attached to each torsion posts 4 and 5 by clamps 7. The semi-cylindrical sleeves 18 and 19 inhibit rotation of the clamps 7 about the torsion posts 4 and 5. In use, a tubular 46 such as casing or drill pipe which forms part of a string, is held in a spider in a floor of an oil or gas rig (not shown). Jaws 47 and 48 of the backup unit 3 are opened and placed around the top of the tubular 46. The top of the tubular 46 is gripped by closing the jaws 47 and 48 of the backup unit 3. The tubular 46 is gripped at a point such that the lip 44 of guide shoe 11 will be above a box 47 of the tubular 46. Springs 8 bias the rear of the guide shoe holder 10 outwardly towards the mouth of the backup unit 3 and hence open. As the backup unit 3 is moved towards the tubular 46, the box 47 contacts the rear of the lower section 45 of the guide shoes 11. The guide shoes 11 move about the box 47 around stub axles (22 and not shown). Once the backup unit 3 has firmly gripped the tubular 46, piston and cylinders 9 are actuated by either hydraulic or pneumatic fluid, engaging and firmly pressing the lower section 45 of the guide shoe 11 against the box 47. A section or stand of tubulars 51 is lowered through jaws 49 and (now shown) of the power tong 2. A pin on the lower end of the section or stand of tubulars is lowered into the box 47, being guided by the top section 42 of the guide shoe 11. The tubular may now be rotated by a top drive to screw the pin into the box to a low torque. The jaws 49 and (not shown) of the power tong 2 are closed and the power tong is activated to torque the connection. Referring now to Figures 7 to 11 there is shown a second embodiment of the apparatus of the present invention generally identified by reference numeral 101. The apparatus 101 comprises a power tong 102 and a backup tong 103. Torsion posts 104 and 105 are arranged between the power tong 102 and the backup tong 103 on opposing sides thereof. Three guide units 106, 107 and 108 are arranged about and fixed to the backup tong 103. The first guide unit 106 is fixed to a left jaw 109 of the backup tong 103, the second guide unit 107 is fixed to a rear portion 110 of the backup tong 103 and the third guide unit 108 is fixed to a right jaw 111 of the backup tong 103. Referring to Figure 10, each guide unit 106, 107 and 108 comprises a bracket 112, a piston and cylinder unit 113, a guide shoe holder 114 and two guide shoes 115. The bracket 112 comprises a base plate 116, a vertical plate 117 arranged at the inner most point of the base plate 116, and two spaced apart strengthening plates 118 arranged therebetween. A piston and cylinder unit 113 is located in a hole 119 through the top of the vertical plate 117. A cylinder 120 is provided with a flange 121 which is attached to the vertical plate 112. A piston 122 extends from the cylinder 120. The guide shoe holder 114 is fixed to a free extend of the piston 122. The guide shoe holder 114 comprises a central block 123 to which upper and lower horizontal bars 124 and 125 are fixed, as can best be seen in Figure 7. Each guide shoe 1 15 is mounted on a block 126 which is movably disposed on a stub axle 127, as can best be seen in Figure 8. The guide shoe 1 15 is similar to that of the first embodiment, in that the guide shoe 115 may be formed from an elastomeric material. The guide shoe 115 has a top section 128 which has an inwardly sloping angled portion 129 and a lower lip 130. A bottom section 131 is substantially flat. The top section is arranged above the guide shoe holder 114. In use, a tubular (not shown) such as casing or drill pipe which forms part of a string, is held in a spider in a floor of an oil or gas rig. Jaws 109 and 110 of the backup tong 103 are opened and placed around the top of the tubular. The top of the tubular is gripped by closing the jaws 109 and 110 of the backup tong 103. The tubular is gripped at a point such that the lip 130 of guide shoe 115 will be above a box of the tubular. The piston and cylinders 113 are actuated by hydraulic or pneumatic fluid to engage the guide shoes 115 with the box and firmly pressing the lower section 131 of the guide shoe 115 against the box. A section or stand of tubulars is lowered through jaws 132 and 133 of the power tong 102. A pin on the lower end of the section or stand of tubulars is lowered into the box, being guided by the top section of the guide shoe 115. The tubular may now be rotated by a top drive to screw the pin into the box to a low torque. The jaws 132 and 133 of the power tong 102 are closed and the power tong is activated to torque the connection.

Claims: Claims: 1. An apparatus for aligning tubulars which apparatus comprises at least one guide (11;115), a tong (2; 102) and a backup unit (3; 103) wherein said at least one guide (11;115) is arranged on or between said tong (2;102) and said backup unit (3;103), characterised in that said at least one guide (11;115) is, in use, movable towards and away from a box of a tubular with respect to said backup unit. 2. An apparatus as claimed in Claim 1, further comprising a piston and cylinder (9;113), wherein said at least one guide is moveable towards and away from a box of a tubular through the operation of said piston and cylinder. 3. An apparatus as claimed in Claim 1, or 2, further comprising an axle (22;125) wherein said at least one guide (11;115) is moveable thereabout. 4. An apparatus as claimed in Claim 1, 2 or 3, further comprising a guide holder (10;114). 5. An apparatus as claimed in Claim 4, wherein two guides (115) are attachable to said guide holder (114). 6. An apparatus as claimed in any preceding claim, further comprising a spring (8) which biases said at least one guide (11) to an open position. 7. An apparatus as claimed in any preceding claim, further comprising at least one torque post (4,5) wherein said at least one guide (11) is attachable thereto. 8. An apparatus as claimed in any preceding claim, further comprising a bracket (106, 107, 108), wherein said at least one guide (115) is moveable with respect to said bracket. 9. An apparatus as claimed in any preceding claim, wherein said at least one guide (11 ; 115) is made from an elastomeric material. 10. An apparatus for aligning tubulars which apparatus comprises a tong (2), a backup unit (3), at least one torsion post (4,5) arranged therebetween, the apparatus further comprising at least one guide (11), characterised in that said at least one guide (11) is mounted on said at least one torsion post (11). 1 1. A method for aligning tubulars using the apparatus as claimed in any preceding claim, comprising the step of moving said at least one guide towards and away from a box of a tubular with respect to said backup unit.

Inventors: LIESS MARTIN, PIETRAS BERND-GEORG, LIESS, MARTIN, PIETRAS, BERND-GEORG
Applicants: HARDING RICHARD PATRICK, LIESS MARTIN, PIETRAS BERND GEORG, WEATHERFORD LAMB, HARDING, RICHARD, PATRICK, LIESS, MARTIN, PIETRAS, BERND-GEORG, WEATHERFORD/LAMB, INC.
Application year: 2000
Main classification: E21B19
IPC codes: E21B19