GB2092496A - Pipe alignment apparatus - Google Patents

Abstract

A pipe alignment tool includes upper and lower pipe clamp assemblies (28, 26) having hinged jaws and connected together in axial alignment by hydraulic cylinders (34, 35) that are selectively operable to adjust the extent of vertical separation of the clamp assemblies. A set of slips (122) on the lower clamp assembly (26) grip the upper end of a pipe joint extending into a well, and a set of rollers (85) on the upper clamp assembly (28) grip the lower end of a pipe joint suspended thereabove in order to hold the adjacent threaded ends of the pipe in precise axial alignment. One of the rollers (85) is driven by a motor (125) to cause the suspended pipe joint to be rotated as the cylinders (34, 35) are operated to slowly lower the suspended pipe joint relative to the first-mentioned pipe joint to at least partially make up the threaded connection. Alternatively, the upper and lower assemblies each have vertically movable sets of slips wedged to grip the pipes. The upper assembly has the slips on a ring rotated by a motor for threading-up. <IMAGE>

Description

SPECIFICATION Pipe alignment apparatus and methods This invention relates generally to methods and apparatus for facilitating alignment, stabbing threading of tubular members such as drill pipe or casing during running of the same into a well.

A long standing problem in the oil drilling industry is to properly align and then join or "make up" threaded tubular members that are being run into a well, particularly large diameter casing that is used to line the well. Prior procedures have involved the use of the cat line and a choke loop to lift pipe joints lying in the "V" door ramp up into the interior of the derrick and then lower the male or pin end of the joint toward the upward looking female or box end of a pipe joint previously run and left hanging in the slips in the rotary table. A member of a special casing work crew known in oil patch parlance as a "stabber" working on a catwalk called a "stabbing board" that is located some 30 to 35 feet above the rig floor attempts to maneuver the pipe and to judge whether it is properly aligned and ready to screw in.

He may use various types of mechnical devices to pull the top of the pipe over while crew members below try to center it, all of which involves a certain amount of guesswork in addition to being somewhat hazardous duty since a joint of 20" casing may weigh about 3,000-9,000 pounds.

During typical pipe stabbing operations, the driller will cause the lower threaded end of the suspend pipe joint to enter and engage the collar looking up, and then he will slack-off on the elevators to allow the full weight of the pipe to be set down on the threads. This procedure has made it quite difficult to properly mate the threads, and has caused galling cross threading and other thread damage. If the damage goes unnoticed and the pipe is lowered into the well, threaded joint failure can occur which may allow the pipe to break in two, or a leak can develop.

Where the threaded connections are hydraulically tested, of course the discovery of a leak dictates that the joint be unscrewed and recoupled, resulting in lost rig time with attendant expense.

The foregoing problems are amplified when attempting to run casing or other tubular goods into a well from a floating drilling vessel that may pitch and roll in heavy seas.

In accordance with the present invention a pipe alignment apparatus comprises an upper clamp assembly and a lower clamp assembly that are connected to one another in axial alignment by adjustable means for controlling the amount of vertical separation of the assemblies. The adjustable means includes one or more hydraulicaily operated rams having their cylinders connected to one of the clamp assemblies and their piston rods connected to the other.Each clamp assembly includes a relatively fixed segment and a pivotally mounted segment that are hinged together, and means are provided for opening the segments to enable the lower clamp assembly to be positioned around the upper end portion of a lower pipe section, and the upper clamp assembly to be positioned around the lower end portion of an upper pipe section, whereupon the clamp assemblies are closed to encircle and grip the respective ends of the pipe sections and thus automatically align the same for threaded engagement. With all or a part of the weight of the upper pipe joint slacked-off on and supported by the upper clamp assembly the adjustable means then is operated to lower the upper pipe section toward the lower pipe section at a controlled rate of descent while the upper pipe section is rotated by suitable means to at least partially make up the threaded connection.

Each of the clamp assemblies has gripping elements mounted thereon that are arranged to be brought into forceful engagement with the outer peripheral wall surfaces of the pipe as the segments are closed. In one embodiment of the present invention the gripping elements on the upper clamp assembly comprise rollers having knurled outer surfaces, and the gripping elements on the lower clamp assembly comprise slips having toothed inner surfaces. The upper and lower gripping elements can be shifted laterally with respect to the longitudinal axis of the assemblies by motor operated cam means. At least one of the rollers on the upper clamp assembly is arranged to be driven so that the upper pipe section can be rotated as it is lowered with respect to the lower pipe section.In another embodiment of the invention the gripping elements on each clamp assembly comprise circumferentially spaced slip elements mounted on annular bowl segments.

The upper bowl segments have downwardly and inwardly inclined expander surfaces and the lower bowl segments have upwardly and inwardly inclined expander surfaces. The slip elements on the upper bowl segments have upwardly facing teeth and inner inclined surfaces that are companion in shape to the expander surfaces on the upper bowl segments, and the slip elements on the lower bowl segments have downwardly facing teeth and inclined surfaces that are companion in shape to the expander surfaces on the lower bowl segments. The respective sets of slip elements are coupled to a vertical position control that can be remotely actuated to cause lateral inward and outward movement of the slip elements with respect to the longitudinal axis of the clamp assemblies.The upper bowl segments are rotatably mounted in a housing and are arranged to be driven by a suitable motor so that the upper pipe section can be rotated as it is lowered with respect to the lower pipe section.

In accordance with a method of the present invention, the manipulative steps comprise suspending one pipe joint with the lower end thereof extending into a well, raising another pipe joint into position above the suspended pipe joint and in general alignment therewith, clamping onto the upper end portion of the suspended pipe joint and the lower end portion of the raised pipe joint with lower and upper clamp assemblies that are connected together in axial alignment with one another by a connection means that is longitudinally adjustable so as to bring the adjacent threaded ends of the pipe joints into precise axial alignment, at least partially supporting the weight of the raised pipe joint on the clamp assemblies, and then lowering the raised pipe joint toward the suspended pipe joint as the raised pipe joint is being rotated in orderto at least partially make up a threaded connection between the ends of the pipe joints.

The use of the method and appartus of the present invention virtually eliminates the haphazard operations and dangerous conditions that have existed in connection with the running of casing and other tubular goods into wells in the past.

The present invention will be best understood in connection with the following detailed description of the preferred embodiments, taken in conjunction with the appended drawings in which: Figure lisa somewhat schematic view of a drill site where tubular goods are being run into the well using the alignment apparatus of the present invention; Figure 2 is a cross-sectional view, with portions in side elevation, of a pipe alignment apparatus in accordance with the present invention; Figure 3 is a top view of the apparatus shown in Figure 2; Figure 4 is a side view of one of the clamp assemblies shown Figure 2; Figure 5 is an enlarged sectional view of a roller means that may be used in the upper clamp assemblies;; Figure 6 is an enlarged cross-sectional to illustrate further detail of the closing motor and drawbar nut arrangement of each clamp assembly; Figure 7 is an enlarged isometric view of one of the plurality of gripping devices used in the lower clamp assembly; Figure 8 is an enlarged fragmentary view of the scroll ring slot system that is used to enable inward and outward movement of the rollers and gripping devices of the respective clamp assemblies; Figure 9 is a cross-sectional view, with portions in side elevation, of another embodiment of pipe alignment apparatus in accordance with the present invention; Figure 10 is a top view of the apparatus shown in Figure 9, Figure 11 is a side view of the lower one of the clamp assemblies shown Figure 9;; Figure 12 is an enlarged cross-sectionai view of a slip segment, bowl, and position control system that is used in the lower clamp assembly; and Figure 13 is a view similar Figure 12 of the rotatable gripping structure used in the upper clamp assembly.

Referring initially to Figure 1, a joint of well casing 10 is shown suspended within the derrick 11 of a drilling rig on elevators 12 that are hung from the traveling block 13. The traveling block 13 is sus pended by cable 14from the crown block 15, and of course the cable is led to a draw works (not shown) on the rig floor that is operated to adjust the vertical position of the elevators 12 and anything hung therefrom within the derrick. A joint of casing 16 that already has been lowered into the well is shown suspended in slips 17 that are positioned in the rotary bushing 18, and another casing joint 19 that eventually will be aligned and threaded to the upper end of the suspended joint 10 is shown resting on the "V" door ramp 20.A pipe alignment apparatus 25 that is constructed in accordance with the principles of the present invention is shown with the lower clamp assembly 26 clamped onto the upper end of the casing joint 16 below its threaded collar 27, and with the upper clamp assembly 28 thereof clamped onto the lower end portion of the suspended casing joint 10 so as to align the lower threaded or pin end 29 thereof for stabbing into the box end of the pipe joint 16 provided by the collar 27. Although the running of well casing is illustrated, other types of tubular goods such as drill pipe and tubing may be run as well.

A stabbing board 30 is attached within the derrick 11 at a considerable distance above the rig floor and provides a work station and walkway for a casing crew member called a "stabber", whose job it is to maneuver the pipe joint 10 into axial alignment with the lower joint 16 so that the threaded connection can properly be made. It will be recognized that due to the distance that this station is above the rig floor and to the weight of the pipe, the stabber has rather hazardous duty and normally will attach himself to the board 30 by suitable safety devices.

The alignment tool 25 is suspended within the derrick 11 on a line that is attached to a height adjusting cylinder 32 that can be extended and retracted through use of suitable pneumatic or hydraulic controls. When the tool 25 is not in use, it can be moved to the side of the derrick 11 to an out-of-the-way position shown in dotted lines in Figure 1 to permit the use of other tools and equipment.

Turning now to Figures 2 and 3 for an illustration of the structural detail of the alignment tool 25, the assembly includes a lower clamp assembly 26 and an upper clamp assembly 28 that are coupled together by diametrically opposed hydraulic rams indicated generally at 34 and 35. The rams 34 and 35 are each double-acting devices that can be selectively extended and retracted in order to adjust the vertical separation of the clamp assemblies 26 and 28. Each of the clamp assemblies comprises a relatively fixed semi-circular segment 36 and a hinged semi-circular segment 37 with the center line of the hydrauic ram 35 defining a hinge axis X-X in a manner such that the hinged segments can be individually opened and closed with respect to their companion fixed segments. As shown Figure 3, the opening and closing of each hinged segment is controlled by a hydraulic ram 38 having its cylinder 39 pinned to a bracket 40 that is welded or otherwise attached to the fixed segment 36. The piston rod 41 of each ram similarly is pinned to a bracket 42 that is secured to the hinged segment 37, so that extension of the ram will cause the hinged segment to swing toward closed position, and retraction of the ram will cause the hinged segment to swing toward the open position shown in phantom lines in Figure 3. Hyd raulic lines (not shown) are connected to the respective ports 43 and 44 of the cylinder 38 so as to supply and exhaust hydraulic fluid to and from the opposite sides of the piston to effect the extension and retraction of the rod 41.The hydraulic lines extend to an operator control console 45 (Figure 1) that is provided with a source of fluid under pressure and a typical valving arrangement the details of which will be readily understood by those skilled in the art and need not be set forth in detail herein.

Each of the fixed segments 36 of the clamp assemblies 26 and 28 includes a bowl 48 having arcuate stiffeners or ribs 49 and 50 welded to the upper and lower outer surfaces thereof. The end portion 51 of each of the ribs that is located opposite the hinge axis X-X has an aperture 52 formed therein. The apertures 52 in the ribs of the lower clamp assembly 26 receive a shaft 53 that forms a depending extension of the cylinder 54 of the ram 34, and the apertures 52 in the ribs of the upper clamp assembly 28 receive a shaft 56 that forms an extension of the piston rod 55 of the ram 34. The lower end of the cylinder 54 has an outwardly directed flange 57 that is bolted by studs 58 to the end portion 51 of the upper rib 49, and another flange 60 that is appropriately secured to the piston rod 55 similarly is bolted by studs 61 to the end portion of the lower stiffener rib 50.Nuts 62 are threaded to the ends of the respective shafts 53 and 56 in order to secure the cylinder and the rod assemblies to the respective clamp assemblies 26 and 28.

The stiffener rib end potions 64 that are adjacent the hinge axis X-X are reduced in thickness and arranged in overlapping relationship with companion end portions 65 of stiffener ribs 66 that are welded to upper and lower outer surfaces of the semi-circular bowl 67 that comprises the hinged segment 37 of each of the clamp assemblies 26 and 28. Axially aligned holes 68 in the respective end portions 64 and 65 receive a shaft 70 that forms an extension of the cylinder 71 of the ram 35, whereas a like arrangement of rib end portions and holes receives a shaft 72 that forms an extension of the piston rod 73 of the ram.Hereagain the assembly is provided with flanges 74 and 75 that are bolted by studs 76 in a mannerto rigidly attach the cylinder 71 to the lower clamp assembly 26 and the piston rod 73 to the upper clamp assembly 28, with nuts 77 being threaded on the lower end of the shaft 70 and a clevis 130 threaded onto the upper end of the shaft 72. The clevis has a hole 131 for attaching the alignment apparatus 25 to the adjusting cylinder 32 so that the apparatus may be suspended within the derrick as shown in Figure 1.

The inner walls of the respective bowls 48 and 67 are each provided with upper and lower inwardly directed flanges 80 and 81 that provide cam tracks for semi-circular scroll rings 82 and 83 that are slidably mounted thereon. In the illustrated embodiment, the upper clamp assembly 28 is provided with a plurality of circumferentially spaced cylindrical rollers 85, as shown in further detail in Figures 5 and 8, having axles 86 extending from the opposite ends thereof and passing through radially elongated holes 87 formed in the cam track flanges 80 and 81 as well as through elongated slots 88 in the scroll rings 82 and 83.The principal axis of each of the slots 88 is skewed somewhat and thus crosses the circle on which the rollers are arranged so that when viewed from above in Figure 3, clockwise rotation of the scroll rings with respect to the cam track flanges 80 and 81 will force each roller 85 to move inwardly toward the center of the clamp assembly 28. Conversely, counterclockwise rotation of the scroll rings will cause the rollers to be shifted outwardly with respect to such center.

Spacer rods 90 are located between the various rollers 85, and extend through arcuate slots 91 in the upper and lower cam track flanges 80 and 81, with the ends of the rods being secured to the scroll rings 82 and 83 by nuts. An oppositely disposed pair of the spacer rods 90 are each connected to a return spring 93 that has one end attached by a bracket 94 to a respective bowl segment 67 or 48, whereby the scroll rings 82 and 83 are returned to the rotational positions shown in the drawings after having been rotated in a clockwise direction as will be described hereafter.

A drawbar arrangement that includes upper and lower plates 100 and 101 that are fixed to a spacer member 102 extend through a window 103 provided by cut out regions of the adjacent ends of the bowls 48 and 67. The ends of the member 102 are rigidly attached to the upper and lower scroll rings 82 and 83 by studs 107 or the like. The outer ends of the plates 100 and 101 are coupled to a take-up nut 104 by a kingpin 105. The nut 104, shown in enlarged detail in Figure 6, has an elongated slot 106 therein that receives the kingpin 105 so as to enable a certain amount of play, and suitable means are provided to enable a limited amount of pivotal rotation of the nut about the axis of the kingpin while maintaining the general directional orientation of the nut shown in the drawing.

A reversibie hydraulic motor 110 is mounted on the hinged segment 37 of each clamp assembly by a plate 111 that extends between the upper and lower stiffener ribs at the outer ends thereof and is fixed thereto by studs 112 (Figure 4). As shown in Figure 6, an opening 113 receives the output shaft 114 of the motor 110, and the shaft has a spline coupling to a drive member 115 that is journaled in a bearing 116 which is bolted to the plate 111 by studs 112. The drive member 115 has threads 118 that are adapted to mesh with the threads 119 of the drawbar nut 104.

The threads 118 and 119 preferably are large acmetype threads, and chamfered surfaces 120 and 121 may be provided as guides. The motor 110 is mounted as shown in a proper orientation so that as the hinged segment 37 is closed toward the fixed segment 36, the threaded end of the drive member 115 automatially engages and aligns with the nut 104. Then operation of the motor 110 causes the nut 104 to be threaded onto the drive member 115 to thereby cause the drawbarto pull the scroll rings 82 and 83 and thus cause their rotation in the clockwise direction when viewed from above in Figure 3. Such rotation forces the rollers 85 laterally inward as previously described so that the knurled outer surfaces thereof engage and frictionally grip the outer wall surfaces of a section of pipe extended therethrough. The hydraulic circuit that supplies fluid under pressure to the motor 110 includes components to enable the motor to stall when a predetermined tension is applied to the drawbar arrangement to thereby keep the inward forces applied by the rollers to the pipe within design limits.

It should be noted that although the scroll rings 82 and 83 are formed in semi-circular segments, when the jaws of the clamp assemblies are closed the segments provide an essentially continuous ring.

Thus rotary movements thereof in order to shift the rollers inwardly or outwardly may be considered as if the segments form a solid or continuous ring.

The upper and lower clamp assemblies 26 and 28 are substantially identical except for the form of the gripping members 122 which are shown in enlarged detail in Figure 7. The members 122 are generally rectangular slip blocks having slightly concave inner faces 123 provided with downwardly facing wickers or teeth 124 that are adapted to bite into the outer wall of the pipe joint 16 as the members are shifted inwardly into engagement therewith. Longitudinally extending bores 125 are adapted to receive the rods that have their ends extended through the slots in the cam track flanges and the scroll rings as previously described, and transverse bores 126 are provided and have threads (not shown) that receive locking pins which are employed to fix the slip blocks along the rods.The amount of concavity of the faces 123 is designed so that the faces fit snugly against the peripheral wall of the pipe, and thus are substantially self-aligning as the apparatus is operated.

The upper clamp assembly 28 can be provided with a hydraulic drive motor 125, as shown in Figure 2, that is appropriately mounted by a bracket 126 to the upper stiffener rib 49 and coupled to at least one of the rollers 85 so as to power the same and cause rotation of the pipe joint that is being engaged by the entire set of rollers. A suitable coupling between the motor 125 and a roller 85 can take the form of sprocket 127 fixed to the upper end of the roller axle and driven by a chain 128 that passes around another sprocket 129 on the output shaft of the motor. Slack in the chain 128 will enable the driven roller 85' to be shifted inwardly and outwardly as previously described.

In operation, the pipe alignmenttool 25, which is suspended in the derrick 11 by the line and the height adjusting cylinder 32, is moved over into alignment with the well bore axis. The hydraulic controls at the control console 45 are activated to open the hinged segments 37 of both clamp assemblies 26 and 28. The tool then is positioned such that the lower clamp assembly 26 is located below the collar 27 of the previously run pipe joint 16, whereupon the lower clamp assembly is closed around the pipe. The drive member 115 of the closing motor 110 automatically engages the nut 104 of the drawbar to cause the scroll rings 82 and 83 to rotate clockwise to bring the members 122 into forceful gripping engagement with the outer periphery of the pipe.Since these members 122 cannot rotate, the entire tool assembly is at this time rigidly fixed to the upper end portion of the pipe joint 16.

The upper pipe joint 10 which has been suspended from the elevators 12 then is approximately aligned with the axis of the well by the stabber, who works on the board 30, and the lower end of the pipe positioned within the jaw segments of the upper clamp assembly 28. Then the upper clamp assembly 28 is closed around the lower end portion thereof with the threaded pin end located somewhat above the collar 27 of the lower pipe joint 16. Hereagain the closing motor 110 of the upper clamp assembly 28 cooperates with the drawbar arrangement and scroll rings to cause the knurled rollers 85 to firmly grasp the pipe. With the rollers 85 engaging the end section of the pipe, it is contemplated that the elevators 12 of the rig can be lowered somewhat so that the entire weight of the pipe joint 10 is slacked off upon, and suspended by, the alignment tool.

However, it will be recognized that full support is not necessary to the operation of the tool, and it may be preferable to suspend at least some of the pipe weight from the elevators 12. Either procedure will cause the pipe joint 10 to be precisely axially aligned with the lower pipe joint 16, whereupon the drive motor 125 may be activated to cause the pipe joint 10 to begin to rotate at a low rpm. Hydraulic fluid then is bled from the rams 34 and 35 below the respective pistons thereof to cause the rams to slowly close or retract, thereby lowering the rotating pin end of the joint 10 toward the stationary box end of the joint 16. As the pin enters the box the threaded connection is at least partially made up under power of the motor 125.Then the alignment tool 25 is released from the pipe joints by reversing the closing motors 110 to unthread the members 115 from the drawbar nuts 104 and actuating the cylinders 39 to open the clamp assemblies 26 and 28.

Now the tool 25 can be moved away to the side so that conventional power tongs or the like can be used to fully tighten the joint to a specified make-up torque value.

The hydraulic circuits that are used to actuate the various cylinders and motors for the operator's console are constructed of well-known components and thus need not be described in detail herein.

Although two rams 34 and 35 are shown, a single ram could be used at the hinge axis X-X, together with suitable means such as a slidable spline connection to prevent relative rotation between the piston rod 73 and the cylinder 71. It also is within the scope of the present invention to use an axial cam means such as a jack with helical threads to adjust the vertical spacing of the clamp assemblies 26 and 28 instead of a hydraulic ram as disclosed.

Turning nowto Figures 9 and 10 for an illustration of the structural detail of another embodiment of an alignment tool in accordance with the present invention, the assembly includes a lower clamp assembly 226 and an upper clamp assembly 228 that are coupled together by diametrically opposed hydraulic rams indicated generally at 234 and 235. The rams 234 and 235 are each double-acting devices that can be selectively extended and retracted in order to adjust the vertical separation of the clamp assemblies 226 and 228. Each of the clamp assemblies comprises a relatively fixed semi-circular segment 236 and a hinged semi-circular segment 237 with the center line of the hydraulic ram 234 defining a hinge axis X-X in a manner such that the hinged segments can be individually opened and closed with respect to their companion fixed segments.As shown in Figure 10, the opening and closing of each hinged segment is controlled by a hydraulic ram 238 having its cylinder 239 pinned to a bracket 240 that is welded or otherwise attached to the fixed segment 236. The piston rod 241 of each ram similarly is pinned to a bracket 242 that is secured to the hinged segment 237, so that extension of the ram will cause the hinged segment to swing toward closed position, and retraction of the ram will cause the hinged segment to swing outwardly and away from the fixed segment to an open position. Hydraulic lines (not shown) are connected to the respective ports 243 and 244 of the cylinder 239 so as to supply and exhaust hydraulic fluid to and from the opposite sides of the piston to effect the extension and retraction of the rod 241.The hydraulic lines extend to an operator control console 45 (Figure 1) that is provided with a source of fluid under pressure and a typical valving arrangement the details of which will be readily understood by those skilled in the art and need not be set forth in detail herein.

Each of the clamp assemblies 226 and 228 includes a bowl 248 that is divided into semi-circular segments, and each segment has arcuate stiffeners or ribs 249 and 250 welded to the upper and lower outer surfaces thereof. Of course it will be recognized that ribs and bowl segments can be formed as integral parts. The end portion 251 of each of the ribs 249 that is located opposite the hinge axis X-X has an aperture 252 formed therein. The apertures 252 in the ribs of the lower clamp assembly 226 receive a shaft 253 that forms a depending extension of the cylinder 254 of the ram 235, and the apertures 252 in the ribs of the upper clamp assembly 228 receive a shaft 256 that forms an extension of the piston rod 255 of the ram 235.The lower end of the cylinder 254 has an outwardly directed flange 257 that is bolted by studs 258 to the end portion 251 of the upper rib 249, and another flange 260 that is appropriately secured to the piston rod 255 similarly is bolted by studs 261 to the end portion of the lower stiffener rib 250. Nuts 262 are theaded to the ends of the respective shafts 253 and 256 in order to secure the cylinder and the rod assemblies to the respective clamp assemblies 226 and 228.

The stiffener rib end portions 264 that are adjacent to the hinge axis X-X are reduced in thickness and arranged in overlapping relationship. Axially aligned holes 268 in the respctive end potions 264 and 265 receive a shaft 270 that forms an extension of the cylinder 271 of the ram 234, whereas a like arrangement of rib end portions and holes receives a shaft 272 that forms an extension of the piston rod 273 of the ram. Hereagain the assembly is provided with flanges 274 and 275 that are bolted by studs 276 in a manner to rigidly attach the cylinder 271 to the lower clamp assembly 226 and the piston rod 273 to the upper clamp assembly 228, with a nut 277 being threaded on the lower end of the shaft 270 and a clevis 230 being threaded onto the upper end of the shaft 272.The clevis has a hole 231 for attaching the alignment apparatus 225 to the adjusting cylinder 32 so that the apparatus may be suspended within the derrick as shown in Figure 1.

As shown in some detail in Figure 9 and in enlarged detail in Figure 12, the housing or bowl of the lower clamp assembly 226 has upwardly and inwarldy inclined annular surfaces 280 and 281 on which are mounted a set of circumferentially spaced slip segments 282. Each slip segment 282 has downwardly facing wickers or teeth 283 on its arcuate uppefr and lower inner faces, as well as inclined inner surfaces 284,285 that are companion in shape to the inclined surfaces 280 and 281 of the bowl. Studs 286,287 are threaded into the bowl and extend through elongated T-shaped slots 288, 289 in the slip segments 282, with the heads of the studs retaining the segments on the bowl, and the slots enabling limited vertical movement of the slip segment relatively along the bowl.An L-shaped bracket 290 is bolted to the lower end of each slip segment 282, with the horizontal reach 291 of the bracket being loosely received in the internal annular recess of a control ring 292. The control ring 292 is bolted to the rods 293 of several cylinders 294 that are fixed to the lower ribs 250, the rods being connected to pistons 294' that can be selectively subjected to hydraulic pressure from above or below through suitable ports and lines (not shown). Extension of the rods will move the slip segments 282 downwardly relative to the bowl, and retraction of the rods will move the segments upwardly. Of course, downward movement will cause the slip segments to be shifted laterally outwardly, whereas upward movement will cause lateral inward movement thereof.

As shown in Figures 9 and 13, the upper clamp assembly 228 includes a fixed outer bowl 296 and a rotatable inner bowl 297, with each bowl being formed in semi-circular sections that together form substantially continuous rings when the clamp assembly is closed around the pipe. An inwardly directed flange 298 that is bolted or otherwise secured to the lower end of the bowl 296 has an upwardly opening guide track 299 that receives the head of guide rollers 300 that are fixed to the lower end of the innner bowl 297 as shown. In a similar fashion, guide rollers 302 are received in an annular, upwardly opening track 303 in the upper end of the outer bowl sections 296. To carry thrust loading, a set of radially directed rollers 304 that ride in an internal recess 305 in the bowl are provided.

The rotatable inner bowl 297 has upwardly and outwardly inclined annular surfaces 308, 309 on which are mounted a set of annularly distributed slip segments 310 that have upwardly facing wickers or teeth 311 on their arcuate inner peripheries and inclined outer surfaces 312 that are companion in shape to the bowl surfaces 308 and 309. Studs 314 that are mounted on the bowl 297 extend through elongated T-shaped slots 315 in each slip segment 310, with the heads of the studs retaining the segments on the bowl, and the slots enabling limited vertical movement of the segments relative to the bowl. An L-shaped bracket 320 is bolted.to the upper end of each of each slip segment 310, with the horizontal reach 321 of each bracket being loosely received in an internal annular recess of a control ring 322.The control ring 322, which also is formed two semi-circular sections, is bolted to the rods 323 of several cylinders 324 that are fixed to the upper ribs 249, the rods being attached to pistons 323' that can be selectively subjected to the pressure of a hydraulic fluid from above or below via suitable ports and lines (not shown). Extension of the rods 323 will move the slip segments 310 upwardly relative to the bowl 297, and retraction of the rods will move the segments downwardly. Of course, upward movement will cause the slip segments 310 to be shifted laterally outwardly, whereas downward movement will cause lateral inward movement thereof.

The upper clamp assembly 228 is provided with a hydraulic drive motor 340, as shown in Figures 9 and 13, that is appropriately mounted by studs or the like to an outer bowl 296. The output shaft of the motor 340 is provided with a pinion 341 that meshes with a beveled ring gear 342 that is fixed to the rotatable bowl segments 297. Operation of the motor 340 causes corresponding rotation of the inner bowl 247, the slip segments 310 and the pipe joint that is being engaged by the slip segments.

As shown in Figure 10, a structure for locking each respective clamp assembly in its closed position includes a hydraulic cylinder 330 pinned to the fixed bowl segment 237 and having its rod 331 pivoted to a latch member 332 that is rotatably mounted on a hinge pin 333. The latch member 332 has a detent 333 and a finger 334 that cooperates with a rod 335 on the hinged bowl segment 236 to capture the rod and thus lock the clamp assembly closed in response to extension of the rod 331. Of course, the retraction of the rod 331 will pivot the latch member 332 away from the lock pin 335 and thereby enable the clamp assembly to be opened.

In operation, the pipe alignment tool, which is suspended in the derrick 11 by the line and the height adjusting cylinder 32, is moved over into alignment with the well bore axis. The hydraulic controls at the control console 245 are activated to open the hinged segments 237 of both clamp assemblies 226 and 228. The tool then is positioned such that the lower clamp assembly 226 is located below the collar 27 of the previously run pipe joint 16, whereupon the lower clamp assembly is closed around the pipe and locked closed through actuation of the cylinder 330. The rods 293 are retracted to cause the slip segments 282 to shift laterally inward to positions where the teeth 283 can bite into and thus grip the pipe joint. Since the slips 282 cannot rotate relative to the bowl, the entire tool assembly is at this point rigidly fixed to the upper end portion of the pipe joint 16.

The upper pipe joint 10, which has been suspended from the elevators 12, then is approximately aligned with the axis of the well by the stabber who works on the board 30. The lower end portion of the pipe is positioned within the jaw segments of the upper clamp asssembly 228. Then the upper clamp assembly 228 is closed around the lower end portion thereof with the threaded pin end located somewhat above the collar 27 of the lower pipe joint 16.

Hereagain the closing motor 330 of the upper clamp assembly 228, which may be either a pneumatic or a hydraulic cylinder, is actuated to cause the latch member 332 and the lock rod 335 to lock the clamp in the closed position, and the cylinders 324 are activated to move the slip segments 310 downward and cause lateral inward shifting of thereof into gripping engagement with the pipe. With the slips engaged, it is contemplated that the elevators 12 of the rig can be lowered somewhat so that the entire weight of the pipe joint 10 is slacked off upon, and suspended by, the alignment tool. However, it will be recognized that full support is not necessary to the operation of the tool, and it may be preferable to suspend at least some of the pipe weight from the elevators 12.Either procedure will cause the pipe joint 10 to be precisely axially aligned with the lower pipe joint 16, whereupon the drive motor 340 is activated to cause the pipe joint 10 to begin to turn to the right at a low rpm. Hydraulic fluid then is bled through operation of a needle valve or the like from the rams 234 and 235 below the respective pistons thereof to cause the rams to slowly close or retract, thereby lowering the rotating pin end of the joint 10 toward the stationary box end of the joint 16. As the pin enters the box the threaded connection is at least partially or perhaps even fully made up under power of the motor 340. Then the alignment tool can be released from the pipe joints by retracting the closing motors 330 and actuating the cylinders 239 to open the clamp assemblies 226 and 228. Now the tool can be moved away to the side if it is more desirable to use conventional power tongs or the like to further tighten the joint to a specified make-up torque value.

The hydraulic circuits that are used to actuate the various cylinders and motors for the operator's console are constructed of well-known components and thus need not be described in detail herein.

It now will be recognized that a new and improved pipe alignment apparatus has been provided. Since certain changes or modifications may be made in the disclosed embodiment by those skilled in the art without departing from the inventive conepts involved, it is the aim of the appended claims to cover all such changes and modifications falling within the true spirit and scope of the present invention.

Claims (18)

1. Apparatus adapted for use in positioning the ends of pipe joints in axial alignment to facilitate the making of a threaded connection therebetween, comprising: an upper clamp assembly and a lower clamp assembly, said lower clamp assembly being adapted to grasp the upper end portion of a pipe joint that extends downwardly into a well and said upper clamp assembly being adapted to grasp the adjacent lower end portion of a pipe joint that initially is suspended above said first-mentioned pipe joint, each of said clamp assemblies including a fixed segment and pivotal segment hinged to said fixed segment, whereby said segments may be opened to permit said end sections to be positioned therein and then closed in order to grasp the same; and means for connecting said clamp assemblies in vertical alignment with one anotherto correspondingly align the said end portions of said pipe joints, said connecting means being operable to lower said upper clamp assembly toward said lower clamp assembly to bring the adjacent ends of said pipe joints into abutting engagement.

2. The apparatus of claim 1 further including means mounted on said upper clamp assembly for rotating said suspended pipe joint as the same is lowered relative to said first-mentioned pipe joint to at least partially make up said threaded connection.

3. The apparatus of claim 2 wherein said upper clamp assembly has first gripping means mounted thereon and said lower clamp assembly has second gripping means mounted thereon, each of said gripping means being adapted to be brought into forceful engagement with outer peripheral wall surfaces of said pipe joints as said segments are closed.

4. The apparatus of claim 3 wherein said first gripping means comprises a plurality of circumferentially spaced roller elements having knurled outer surfaces and said second gripping means comprises a plurality of circumferentially spaced slip elements having toothed inwardly facing arcuate wall surfaces.

5. The apparatus of claim 4wherein said rotating means includes motor means coupled to at least one of said roller elements.

6. The apparatus of claim 4wherein each of said roller elements and said slip elements are mounted for inward and outward movement on said clamp assemblies; and means for forcing said rollerele- ments and said slip elements inwardly against wall surfaces of said pipe joints upon closure of said segments.

7. The apparatus of claim 6 wherein said forcing means comprises cam means including ring segments rotatably mounted on each of said clamp assemblies, rotation of said ring segments in one rotational direction causing inward movement of said roller and slip elements and rotation of said ring segments in the opposite rotational direction causing outward movement of said roller and slip elements; and motor means mounted on said clamp assemblies for rotating said ring segments in said one rotational direction.

8. The apparatus of claim 7 further including bias means for aiding in rotating said ring segments in said opposite rotational direction.

9. The apparatus of claim 3 wherein said first and second gripping means each comprise a plurality of circumferentially spaced slip elements having toothed inwardly facing wall surfaces.

10. The apparatus of claim 9 wherein each of said slip elements is mounted for movement between an inner extended position and an outer retracted position; and further including inclined surface means on said segments and the outer walls of each slip element for shifting said slip elements between said extended and retracted positions.

11. Theapparatusofclaim 10furtherincluding first selectively operable means for controlling the shifting of the slip elements on said upper clamp assembly between said extended and retracted positions; and second selectively operable means for controlling the shifting of the slip elements on said lower clamp assembly between said extended and retracted positions.

12. The apparatus of claim 11 wherein said first controlling means comprises ring means mounted for vertical movement on said upper clamp assembly, and linkage means for connecting each of the slip elements on said upper clamp assembly with said ring means.

13. The apparatus of claim 11 wherein said second controlling means comprises ring means mounted for vertical movement on said lower clamp assembly, and linkage means for connecting each of the slip elements on said lower clamp assembly with said ring means.

14. The apparatus of claim 3 wherein said upper clamp assembly includes inner and outer bowl means, said inner bowl means being mounted for rotation relative to said outer bowl means, said first gripping means being carried on said inner bowl means.

15. The apparatus of claim 14 wherein said rotating means comprises motor means on said outer bowl means having gear means meshed with companion gear means on said inner bowl means.

16. A method for facilitating the making of threaded connections between successive pipe joints as they are being run into a wall, comprising the steps of: suspending a pipe joint with the lower end thereof extending into the well; raising another pipe joint into position above the suspended pipe joint and positioning it in general alignment therewith; clamping onto the upper end portion of the suspended pipe joint and the lower end portion of said other joint with upper and lower clamping assemblies that are connected together in axial alignment with one another by a connection means that is longitudinally adjustable, said clamping steps bringing the adjacent threaded ends of said pipe joints into precise alignment; at least partially supporting the weight of said other pipe joint on aid clamping assemblies; ; lowering said other pipe joint toward the suspended pipe joint by adjusting the length of said connecting means to bring the adjacent threaded ends of said pipe joints into abutting contact; and rotating said other pipe joint as it is being lowered relative to said suspended pipe joint to at least partially make up said threaded connection.

17. Pipe alignment apparatus substantially as hereinbefore described with reference to and as illustrated in any of the accompanying drawings.

18. A method of aligning piping substantially as hereinbefore described with reference to and as illustrated in any of the accompanying drawings.