Patent Application
20080307930
1. Field of the Invention
The present invention relates generally to power tongs and, more specifically, to power tongs that may be used for making and breaking connections in oil well tubular strings such as drill pipe and casing.
2. Description of the Prior Art
Power tongs have been used for many years for making and breaking tubular connections. However, as power tong systems have become larger and heavier so as to include back-up grips, spinners, and other valuable features that reduce time and improve reliability of the made up tubular connections, it has become necessary to build tracks and the like to control movement of the power tongs on the rig floor. The large size of and heavy weight of modern power tongs makes cable supports a less desirable means of supporting such systems. Movement of large heavy power tong systems either laterally or rotationally produces logistics problems on the rig floor and increases the likelihood of accidents.
Representative patents and publications seeking to solve such problems and related issues include the following:
U.S. Pat. No. 4,492,134, issued Jan. 8, 1985, to Reinholdt et al., discloses a power tongs for threadedly connecting together pipes which are to constitute casings for boreholes, which has a platform for a reciprocable slide which supports a power-driven threading clamp and a counter device. The clamp and the counter device are connected to each other by several level compensating hydraulic cylinders each of which is movable horizontally within limits relative to the slide against the opposition of resilient support elements. The upper end portions of the cylinders are connected to a holding plate for the clamp.
U.S. Pat. No. 4,082,017, issued Apr. 4, 1978, to Emery Eckel, discloses a hydraulically or pneumatically powered drill pipe tongs of the scissors-type used in making up or breaking apart joints of drill pipe, drill collars, and the like including an upper tong and a lower tong each including tong die heads for biting into or gripping the upper and lower joints of drill pipe, drill collars and the like with the upper and lower tongs being swivel connected and being swiveled by a hydraulically or pneumatically powered torqueing piston and cylinder assembly for rotating the upper and lower tongs in relation to each other when making up or breaking apart the drill pipe joints. Each of the upper and lower tongs includes a sliding door having one of the tong die heads thereon that can be moved a substantial distance toward and away from the tong body by the use of a pair of hydraulically or pneumatically powered piston and cylinder assemblies to enable tool joints, drill pipe protectors and the like to pass through the tongs while leaving the tongs on the pipe. Each of the tongs also includes a hinged mounting for one edge portion of the tong door and a latch for the other edge portion to enable the tong door to be latched or unlatched and swung outwardly in a manner to enable the tongs to be removed from the drill pipe when necessary.
U.S. Pat. No. 5,081,888, issued Jan. 21, 1992, to Joerg E. Schulze-Beckinghausen, discloses an apparatus for connecting and disconnecting threaded members including a power tong, a backup unit disposed below the power tong for tripping a second pipe, and apparatus for transmitting reaction forces generated by the power tong to the backup unit, the backup unit having devices for transmitting compressive or tensile forces between its members from the power tong which, in one embodiment, includes a hydraulic connection between a double acting hydraulic piston and cylinder assemblies incorporated in the members.
U.S. Pat. No. 6,138,776, issued Oct. 31, 2000, to Hart et al., discloses a pipe handling system comprising a rig floor supported frame adapted to be positioned above the rotary table and in alignment with the hole in the rotary table. It incorporates a centrally located bowl lined with the frame to enable a string of pipe to extend through the rotary table. Appropriate releasable slips are moved into and out engagement. The frame supports an overhead mounting plate, and one version thereof incorporates hydraulic jacks to raise and lower the mounting plate. The mounting plate supports a horizontally directed hydraulic ram which moves the two end lengths of a long multi length chain looped into a bight to go around a pipe passing near the end of the mounting plate. The bight in the chain grips the coupling of the pipe to hold it fast. This mechanism cooperated with an overhead power tong assembly to enable threading or unthreading of pipe casing and tubing.
U.S. Pat. No. 4,515,045, issued May 7, 1985, to Gnatchenko et al., discloses an automatic wrench comprising a high-torque, a low-torque, and a locking device. The wrench control system includes a torque detector and a rotation angle detector, in response to whose signals passing through an AND gate a control unit delivers a command to end the thread tightening by the rotation actuator of the high-torque device in screwing a pipe string together or to end the initial loosening of the thread with the aid of the same actuator in screwing it apart. The control unit incorporates a unit for monitoring the duration of the command execution, which stops operation of the high-torque device if no signal comes from said AND gate during the time allotted to accomplish the tightening or the initial loosening of the thread.
U.S. Pat. No. 5,271,298, issued Dec. 21, 1993, to Gilles Gazel-Anthoine, discloses a machine for screwing and unscrewing two rods, comprising an annular carcass forming a frame about a central axis and, staggered in height on the carcass, upper and lower wrenches each adapted to grip two successive rods. One of the wrenches, referred to hereinafter as the rotary drive wrench, is mounted rotatably relative to the carcass and the rotary drive wrench at least comprises a plurality of cams distributed circumferenfially and each mounted to pivot about an axis parallel to the central axis between a retracted position in which they leave around the central axis a space sufficient for the rods to pass through and a deployed position in which they intrude on the space and are able conjointly to grip a rod present in the latter. The machine is useful in drilling installations.
U.S. Pat. No. 6,142,041, issued Nov. 7, 2000, to David A. Buck, discloses a power tong positioning apparatus, including a power tong support positionable on the surface of drilling rig deck and attachable to at least one power tong. The power tong support is adapted to position at least one power tong so that it may engage the tubular member. The power tong positioning apparatus a frame, a base moveably positioned on the frame, at least one arm pivotally attached to the base, a power tong support pivotally attached to the arm(s) and movably attachable to at least one power tong.
U.S. Pat. No. 6,142,040, issued Nov. 7, 2000, to Vernon J. Bouligny, discloses a spider, preferably a flush mounted spider, and powered lead tong which are coupled by a rotationally rigid structure so that torque reaction forces apply no side load to pipe. The tong preferably tilts upward to clear larger objects approaching the spider. An optional grabber is mounted, preferably atop the lead tong, and may tilt with the lead tong. Fluid powered motors, linear or rotary, provide the tilting energy and extend and retract the grabber. The tong and related structure has quick coupler provisions for removal from the spider.
Farrcanada provides a tong assembly on a track that moves along a track to engage the tubular connections as shown at website www.farrcanada.com.
The above power tong systems show tongs that either move laterally with respect to the pipe and/or have outer housings that rotate around the pipe and/or do not include a complete power tong assembly capable of spinning, backing up, applying torque, automatic slips, and the like. Consequently, it would be desirable to provide a system and method that is designed to avoid lateral and rotational movement of large power tong housings and provide virtually all functions required at the rig floor for making and breaking connections of either drill pipe or casing. Those skilled in the art will appreciate the present invention that addresses the above and other needs and problems.
Accordingly, it is an object of the present invention to provide an improved power tong system and method.
It is yet another object of the present invention to provide an improved system and method for performing making and breaking functions at the rig floor with improved safety features.
It is yet another object of the present invention to provide an improved system that provides virtually all functions of making and breaking pipes at the rig floor without the need for movement of large housings either laterally or rotationally around the pipe.
These and other objects, features, and advantages of the present invention will become apparent from the drawings, the descriptions given herein, and the appended claims.
Therefore, in accordance with the present invention, an apparatus is disclosed for a power tong system for making and breaking connections in a tubular string. The power tong system may be used on a rig floor and comprises one or more elements such as a power tong housing, and at least one rotary drive tong mounted within the power tong housing for encircling and gripping a first portion of the tubular string. The rotary drive tong preferably has a rotatable gear therein for applying rotational force to the first portion of the tubular string. Other elements may include at least one backup tong having gripping elements therein for holding a second portion of the tubular string while the rotary drive tong applies the rotational force to the first portion of the tubular string. A plurality of lift assemblies may each include slidable shafts for moving the power tong housing upwardly and downwardly. The plurality of lift assemblies may be secured with respect to the rig floor such that the power tong housing is moveable upwardly and downwardly with respect to the rig floor and such that the power tong housing is prevented from rotating with respect to the rig floor.
Preferably the system includes powered slips operable for powered movement of slips into and out of gripping engagement with the tubular string. The powered slips are operable for supporting a weight of the tubular string.
In one embodiment, a collar locator produces a collar locator signal in response to at least one of the connections in the tubular string. A tong control is responsive to the collar locator signal for automatically controlling the upwardly or downwardly movement of the power tong housing for positioning the rotary drive tong and the backup tong with respect to one of the connections.
As an added feature of the invention, either the collar locator itself, or a separate detector, for example, a magnetic flux detector, can be used as an inspection device to locate cracks, holes, leaks and other anomalies in the tubulars being made up or broken out of an oil well tubular string.
A drive gear may be provided within the at least one rotary drive tong which completely encircles the tubular string. A plurality of cams may be mounted to the drive gear for movement therewith. A removable section for the drive gear may be provided such that when removed the drive gear can be laterally moved away from the tubular string.
An expandable connection may be provided between the rotary drive tong and backup tong to permit relative up and down movement therebetween. Moreover, an extension member may be used for connecting between the at least one rotary drive tong and the at least one backup tong to permit the rotary drive tong and the backup tong to both grip either on a respective portion of the connection or simultaneously above and below the connection.
A plurality of piston driven gripping elements may be provided within the backup tong for selectively engaging and disengaging the second portion of the tubular string.
Thus, in one embodiment, the power tong system may comprise at least one rotary drive tong for gripping a first portion of the tubular string having a rotatable gear therein for applying rotational force to the first portion of the tubular string and at least one backup tong having gripping elements therein for holding a second portion of the tubular string while the rotary drive tong applies the rotational force to the first portion of the tubular string. A plurality of lift assemblies move the rotary drive tong upwardly and downwardly with respect to the rig floor. The plurality of lift members may be secured with respect to the rig floor. Powered slips are preferably provided that are operable for powered movement of slips into and out of gripping engagement with the tubular string for supporting a weight of the tubular string as desired. As well, a preferred embodiment includes a collar locator for producing a collar locator signal in response to at least one of the connections in the tubular string, and a control responsive to the collar locator signal for automatically controlling the upwardly or downwardly movement of the plurality of lift members.
The collar locator may be of various types and may include an electronic proximity detector for the collar locator such as circuitry for detecting variations in a magnetic field or circuitry for detecting variations in a transmitted signal.
A method for making or breaking connections in a tubular string as the tubular string is run into or out of a wellbore may comprise steps such as providing a power tong housing with a rotatable drive gear therein such that the power tong housing remains encircling the tubular string as the tubular string is run into or out of the wellbore. Other steps may include securing a back up power tong with respect to the power tong housing and/or moving the rotary drive tong and the back up power tong in a direction substantially parallel with respect to the tubular string. In a preferred embodiment, the method of the invention may comprise steps such as supporting the rotary drive tong to prevent rotation of the power tong housing during the making or breaking of the connections and/or producing an electronic signal in response to locating a connection. The method may further comprise positioning the rotary drive tong and the power tong backup in response with respect to the tubular string in response to the electronic signal.
A more complete understanding of the invention and many of the attendant advantages thereto will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein corresponding reference characters indicate corresponding parts throughout the drawing and wherein:
Referring now to the drawings and, more particularly to
It will be understood that such terms as up, down, vertical, and the like, are made with reference to the drawings and/or the earth and that the inventive devices may not be arranged in such positions at all times depending on variations in operation, transportation, and the like. It will also be understood that the drawings are intended to describe the concepts of the invention so that the presently preferred embodiments of the invention will be plainly disclosed to one of skill in the art but are not intended or required to be manufacturing level drawings or renditions of final products and therefore may include simplified conceptual views as desired for easier and quicker understanding or explanation of the invention. As well, the relative size and relative dimensions of the components may be greatly different from that shown.
In
Referring now to
Since tong system 10 is already positioned correctly laterally, it is only necessary that power tong housing 36 be moved upwardly or downwardly, i.e., axially along pipe string 18 in a direction substantially parallel to pipe string 18 until power tong housing 36 is adjacent connection 22. For this purpose, powered lift assembly 41 is preferably used whereby shafts 42 may preferably be telescopically mounted with respect to cylinders 44 and/or 46. Shafts 42 may therefore extend or retract with respect to cylinders 44 and/or 46. In this manner, powered lifts thereby extend or retract power tong housing 36 so as to locate power tong housing 36 adjacent connection 22. Power for powered lift assembly 41 may include hydraulic, pneumatic, or electric power. Other means for operating powered lifts or constructions of powered lift assembly 41 could also be used. For instance, a screw drive might be used. A single cylindrical powered lift might be used whereby the cylinder surrounds pipe 18. However regardless of construction thereof, preferably openings such as opening 48 are provided for power lift assembly 41, so that power tong system 10 can be moved laterally with respect to pipe string 18, if and when necessary.
Preferably powered lift assembly 41 is securely fastened with respect to rig floor 12. In many cases, rig floor 12 will often have standard openings therein that can be used for this purpose. If cross bars or supports are used between shafts 42, then one portion of the cross bars or shaft would then preferably be removable. Thus, foot elements 50 are preferably fixably secured to rig floor 12 to prevent any movement of foot elements 50 with respect to rig floor 12. Some slight movement or preferably adjustments, usually less than one inch, may be made as necessary to centralize pipe string 18 with respect to the power tongs with adjustment elements located at a convenient position of tong system 10. Thus, rotational movement of power tong system 10 is preferably substantially or completely prevented so as to avoid the safety problem of having large equipment rotate. Moreover, the secure fastening permits secure upward and downward movement of power tong housing 36 with respect to rig floor 12 without permitting rotational movement of power tong housing 36.
As an example of operation, as drive gear 52 rotates as shown by arrow 64, then cams 66 wedge slips 68 radially inwardly to thereby force grips 70 to engage and thereby grip pipe string 18 for applying rotational force thereto. The use of a ring gear, such as drive gear 59 that completely encircles pipe string 18 is desirable to distribute forces and provide a longer lasting system. However, a ring gear that completely encircles pipe string 18 would prevent tong system 10 from the capability of moving laterally for removal of the system, if desired. While tong system 10 could also be moved either by lowering the pipe below ring gear 59 or by lifting tong system 10, it may be desirable to permit lateral movement thereof. For this purpose, housing 36 preferably includes an opening, which may comprise removable housing section 72. Also, in one preferred embodiment drive gear 52 includes removable gear section 74. Thus, upon removing removable gear section 74, and removable housing section 72, then tong system 10 can be laterally moved with respect to pipe string 18 when desired or necessary.
Rotary drive 38 preferably provides all rotating functions including spinning and torqueing. Preferably, rotary drives 54, 56, 58, 60 have high and low geared speeds such that in low gear very high torque is produced with a very low rotational speed. In high gear, much less torque is produced but the rotational speed is quite high so that spinning operation takes place rapidly. However, if desired, separate drives, such as drive 38 in accord with the present invention, could be specifically designed for spinning and for torqueing although having one rotary drive to perform both functions is presently considered more efficient.
For simplicity,
As rotary drive tong 38 rotates one pipe while backup tong 40 holds the other pipe stationary, relative axial movement occurs between tong 38 and tong 40 due to the threads making up or breaking. Referring to
In
However, for the situation where it is necessary that rotary drive tong 38 and backup tong 40 be positioned on the enlarged or upset portions of a connection, such as shown in
The same magnetic flux detector used for locating a collar, or an analogous type of detector can be used to detect a decrease in the metal of a tubular, and thus detect cracks, holes, leaks or other anomalies in the tubular being made up or broken out of the oil well tubular string. Using techniques well known in the electronic art, the collar locator and the anomaly detector can be the same detector using time share or time multiplexing, or the like, or can involve the use of separate devices for the two functions.
In summary, power tong system of the present invention preferably provides a wrap-around tong for performing all operations of making and breaking joints including spinning and torqueing joint connections without the need for lateral movement with respect to pipe string 18. Preferably powered slips, such as representative powered slips 34, are used as part of the system. Moreover, preferably a collar locator and processing means are provided for automatic positioning of the rotary drive tong 38 and backup tong 40 in accord with the present invention.
Numerous variations of the above system and method are possible, some of which have already been described. Therefore, it will be understood that many additional changes in the details, materials, steps and arrangement of parts, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.
