Abstract:
A combination torque wrench and positioning assembly are used to provide the torque wrench function to both make up/break out pipe stands and to service drill string. While serving to make up/break out pipe stands, the wrench is positioned over and used in conjunction with a rotary or powered mouse-hole. When servicing drill string, the wrench is positioned over the drill bore rotary table. The combination of the present apparatus allows the rapid make up of pipe stands having individually torqued connections, eliminates the need for top drive torquing, and reduces the need for tongs and spin chains to handle drill pipe.

Description:
FIELD OF THE INVENTION 
     The present invention pertains to oil rig drill pipe handling devices and procedures. More particularly, it pertains to an apparatus including a duplex drill pipe wrench for both making up and breaking out drill pipe joints, and a method of use in combination with a rotary mouse-hole tool for making up and breaking out multi-joint stands of drill pipe. Still more particularly, the present invention pertains to a device and an improved method for both making up and breaking out multi-joint stands of drill pipe during top drive drilling operations. 
     BACKGROUND OF THE INVENTION 
     Oil well drilling operations usually involve rotating a string of drill pipe composed of individual sections called “joints,” each typically 30 feet in length, which carries a drill bit assembly at its lower end. As the bit bores deeper into the earth, additional joints of pipe are added to the string (see A Primer of Oilwell Drilling, (1979) Petroleum Extension Service, University of Texas, Austin, Pub., 1979, incorporated herein by reference). 
     The “top drive” is a relatively recent development in mechanisms for rotating a drill pipe string that has gained widespread acceptance in the oil and gas drilling industry. A top drive drilling mechanism and ancillary equipment are supported by and below the traveling block of a drilling rig. The traveling block provides for moving the top drive vertically along the well bore axis to enable connecting it to the drill string. The top drive mechanism includes a drive mechanism which turns a coupling to which the upper end of the pipe string can be connected. Top drive drilling procedures eliminate the need for the long “kelly joint” previously used for connecting a drive mechanism to a drill pipe string, and the need for disconnecting the kelly joint from the drill string each time it is necessary to add or remove a single section from the drill string. Also, use of a top drive permits drill pipe to be added to the drill string in multi-joint “stands” of two or three sections of drill pipe at a time, with a corresponding reduction in time wasted and man hours expended by not having to cease drilling as often to add drill pipe. 
     The mouse-hole and the rat-hole are rig features previously developed in connection with rotary table drilling rigs. A mouse-hole is a substantially vertical tubular sleeve extending below the drilling rig floor with its upper opening adjacent the drill bore. The mouse-hole is used to hold the next joint of drill pipe which is to be added to the drill string. The rat-hole is a somewhat larger diameter (and often longer) tubular sleeve also located in the drilling rig floor and serves as a receptacle for the kelly. 
     To realize the advantages obtainable with top drive systems, it is desirable to make-up stands of drill pipe while drilling operations are in progress. However, for a variety of reasons, the task of making up multiple stands of up to three sections of drill pipe often cannot be completed fast enough to keep up with drilling operations. Consequently, the maximum efficiencies possible from use of top drive drill procedures are not always obtained. Therefore, an important step in a top drive drilling procedure is the make up or connection of one pipe joint to another, in advance. 
     A problem attendant with this step is the need to insure the application of the proper amount of torque to the ends of the joints being connected. Usually, torque is measured only overall, when the multi-joint stand is attached to the top drive unit, in which case, there is no measurement or control of torque at each connection between joints in the stand. 
     Another problem commonly encountered when making up “double” and “thribble” (as they are called in the art) stands for top drive drilling is to ensure proper alignment of the “tool joint” ends. Each section of drill pipe has an externally threaded coupling at one end, called a “pin”, and at the other end, an internally threaded coupling called a “box.” Drill strings typically are assembled with each joint in the string joint disposed pin end down. Misalignment of the pin and box ends of adjacent joints can slow the task of making up a stand and can lead to galling or other thread mutilation conditions. 
     Some top drive drilling procedures actually require the use of the top drive in the make up of joint stands. Those types of procedures that require participation of the top drive in operations other than drilling may not be making full use of the advantages top drive drilling is now recognized as offering the industry. 
     A need exists in the industry for alternatives and improvements in the procedures and equipment available in top drive drill rigs to enable more rapid assembly of multi-joint stands of drill pipe, while drilling operations are concurrently proceeding. Such improvements desirably should include procedures and devices for (1) accurately and efficiently aligning the pin and box ends of two joints to be connected, (2) threading those joints together (or unthreading them for breakout), (3) applying a determined amount of torque to finish the connection (or break the connection for a backout), and (4) not requiring participation of the top drive to accomplish any of the make up operations. Further, the equipment should be flexible for use with existing drill rig arrangements and procedures to reduce the need for retraining of rig personnel. 
     The recognized advantages of top drive drilling in fact have motivated the industry to develop innovative technologies and improvements which support or attempt to optimize those advantages. Specifically, the advantage of being able to attach to the drill string multiple sections of drill pipe at-a-time has led to the development of new devices and methods for making up and breaking out multi-joint drill pipe stands. 
     Kennard (U.S. Pat. No. 3,293,959) discloses a device mounted over the rat-hole on a drilling platform. Kennard describes using a kelly joint for rotation, a housing and means for supporting a length of pipe to be added to the drill string, and clamping means for preventing the pipe from rotation during make-up with the kelly joint. The housing is mounted on spring legs to resiliently support and upwardly bias the joint to be made up relative to the kelly joint. A winch having a cable and stabbing hook swings the kelly joint into position over the housing and vertically aligns it with the pipe joint supported by the housing. 
     Stogner et al. (U.S. Pat. No. 5,351,767, herein incorporated by reference) teach an apparatus and method where multi-joint stands of drill pipe are made up and broken out in a drilling rig using a rig&#39;s mouse-hole feature. In Stogner et al., make up and break out are accomplished by using a powered mouse-hole to rotate a lower joint of pipe relative to an upper joint, which is held in alignment and prevented from rotating by tong assembly. However, this apparatus and method do not accomplish the controlled torquing of each connection between joints in a stand. 
     Additionally, Stogner et al. describe a rotating mouse-hole tool for use with a standard mouse-hole in situations where the drilling rig does not have a powered mouse-hole available. The rotating mouse-hole tool itself provides the rotational force for threading and unthreading joint of drill pipe. The rotating mouse-hole tool of Stogner et al. is to be used with a particular type of drill pipe that has a neck formed by increasing the diameter of the coupling end of the pipe (described in Stogner et al. as known in the art as “a tool joint box”). 
     The PHANTOM MOUSE® (International Tool Co., Ltd., Houston, Tex.) is a commercially available example of a rotating mouse-hole tool for tool joint make up and break out. However, rotating mouse-hole tools generally do not make up the joint connection to full torque, and a stand of pipe is tightened to full make up torque only after it is inserted into the drill string by means of the top drive. Make up torque is applied overall to the stand, not individually to each connection. This procedure consumes top drive operating time and can result in variation in the make up torque of individual connections in stands of more than two sections of drill pipe, or in the connection of the stand to the drill string. Another limitation of the rotating mouse-hole tool is that it is not easily usable on drill string. 
     SUMMARY OF THE INVENTION 
     The object of the apparatus of the present invention is a duplex drill pipe wrench and positioner combination for use with a powered mouse-hole or rotary mouse-hole tool in a top drive drilling procedure. The present invention makes it possible on top drive rigs for the drill pipe connections made up in a powered mouse hole or using a rotating mouse-hole tool to be torqued up to a full 70,000 foot pounds for 3-inch drill pipe through 8½-inch drill collars. This means that pipe stands made up using the present apparatus and method can be made up at full torque to be ready to go down hole when needed without any further torquing. 
     Another object of the present invention is to eliminate any need for spinning chains or tongs, hence eliminating prior safety problems associated with tongs and chains. 
     Another object of the present invention is a procedure allowing drilling crews to keep on drilling and making hole while they simultaneously make up and set back stands of drill pipe, or break out and lay down excess drill pipe that has been left in the derrick. The present duplex drill pipe wrench and positioner combination is mounted on the drill rig so that it may be positioned either just above the powered mouse-hole (or a rotating mouse-hole tool) or the rotary table (over the well bore). In this configuration the duplex drill pipe wrench can be used to service either drill pipe in the mouse-hole or drill pipe in the drill string. 
     The apparatus of the present invention is a duplex drill pipe torque wrench assembly, which is connected to a wrench holder. The wrench holder is located on a drilling rig so that it can be used to position the bore of the jaws of the wrench in line with the vertical bore of a mouse-hole and/or the vertical bore of the well. The duplex drill pipe wrench serves the dual purpose of: (1) a torque wrench and (2) a backup wrench. Additionally, the present wrench serves the dual purpose of: (1) aligning and holding the mating ends of two sections of drill pipe while they are threaded in or threaded out, and (2) applying the proper torque across a mated connection to make up the connection or to break out the connection. The present invention also serves the dual purpose of: (1) make up/break out of pipe stands over a mouse-hole, and (2) servicing drill string in the well bore over a rotating table. 
     The present invention is a drill pipe handling apparatus for use on a drilling rig comprising a duplex drill pipe wrench movably connected to a positionable wrench holder located on a drilling rig within reach of a mouse hole and the rotating table, and capable of alternatively positioning the wrench over the bore of either. 
     The duplex drill pipe wrench has a set of upper jaws and a set of lower jaws stacked in a horseshoe-like configuration to have concentric bores, with their open ends aligned for receiving, aligning and releaseably engaging the opposing ends of two drill pipes. The stacked jaw sets have a biasing means between them which allow for adjusting the distance between them as the wrench performs its threading or unthreading function. This biasing may be accomplished by any of a number of means known to one of skill in the art including adjustable: spring loaded standoffs; shock absorbers; and scissor jacks. 
     Each set of jaws is hydraulically activated to reversibly engage the end of a drill pipe adjacent the coupling. Also, each set of jaws has a first jaw that is manually adjustable to concentrically position different diameters of pipe in the bore of the jaws. The first jaw may be manually positioned by a number of means known in the art, including a screw thread, a detent and a lock pin. The second jaw is hydraulically positionable by activation of a hydraulic piston connected to it. Additionally, the upper set of jaws of the stacked horseshoe configuration is reversibly rotatable relative to the lower set of jaws about the axis of the concentric bore through about 30 degrees by means of a hydraulic piston. The purpose of this feature is to apply the torque necessary to make up or break out joint connections. A housing contains the stacked jaw sets as an assembly and can provide a mount for the assembly&#39;s controls. 
     The positionable wrench holder of the present invention comprises an upright post mounted on the rig, having an arm with one end connected to the upright post and extending radially outward. The arm is positionable up and down the length of the post, and also rotatable around the girth of the post. Further, the arm is movably connected to the duplex drill pipe wrench. Alternatively, the arm of the positionable wrench holder may comprise a track on which the duplex drill pipe wrench is movably connected by wheels for positioning the wrench radially with respect to the post. Additionally, the arm and post may comprise a crane having tackle for connecting to and suspending the duplex drill pipe wrench from the arm at various heights, and/or for positioning the wrench radially with respect to the post. 
     A further object of the present invention is a method for making up a connection between two individual sections of drill pipe, where each section has a complementary threaded pin and box coupling at either end. The steps of this method include providing a drilling rig mouse-hole with means for rotating a drill pipe; inserting a first drill pipe partially into the mouse-hole; and engaging the first drill pipe in the mouse-hole rotational means. Then, using the positionable wrench holder, the duplex drill pipe torque wrench is positioned to receive the upper coupling of the first drill pipe, align its axis with that of the bore of the wrench jaws. After receiving and aligning the upper coupling, the first drill pipe is engaged adjacent the upper coupling with the lower jaws of the wrench. 
     Next, a second drill pipe is suspended vertically in line with the axis of the first drill pipe, with the complementary coupling of the second drill pipe down and in proximity to be received, aligned and engaged by the upper jaws of the duplex drill pipe wrench. The second drill pipe is received, aligned and engaged by the upper jaws of the wrench in a manner similar to the first pipe. Then, the wrench is adjusted to partially disengage the first drill pipe to allow it to rotate along its axis while maintaining it alignment with the second pipe. The second drill pipe continues to be held fixed to prevent its rotation. This action, in combination with the biasing means allows mating of the complementary couplings of the two drill pipes. 
     The mouse-hole rotational means is then activated to rotate the first drill pipe and thread the complementary couplings together. The mouse-hole rotating means is then deactivated after the complementary couplings are fully threaded together. The wrench is then readjusted to fixably engage the first drill pipe to prevent rotation along its axis, and the connection between the two drill pipe sections is made up to full torque by the torquing means of the duplex drill pipe wrench to fully make up an individual connection between the two sections of drill pipe. 
     While a number of objects and advantages are disclosed above, it is well within the ability of one skilled in the art, in view of the present teachings, to conceive of additional objects and advantages that are still within the scope and spirit of the invention as a whole as disclosed herein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows the apparatus of the present invention as a crane and wrench assembly mounted on the deck of a drilling rig, and positioned over a powered mouse-hole for servicing drill pipe stands. Also shown in the figure is the proximity of the rotary table and well bore within reach of the crane. 
     FIG. 2 is a side view of the stacked jaw sets of the duplex drill pipe wrench shown without the housing. 
     FIG. 3 is a cut-away, superior view of the duplex wrench through the housing and with the upper jaw set and head of torque piston removed. Shown are the lower jaws, the horseshoe-like open end alignment feature, and jaw and housing shims for aligning drill pipe in the wrench. Particularly shown are a curved rail-slot concentric to the bore (+) of the jaws and rail-guides. 
     FIG. 4 is a cut-away type superior view of an upper jaw set without the housing, torque piston cylinder and lower jaw set. Shown as if looking through the jaw set is a curved rail, the curvature of which is concentric to the bore of the jaws. 
    
    
     The drawings are not necessarily to scale and certain features of the invention may be exaggerated in scale or shown in schematic form in the interest of clarity and conciseness. It will be readily apparent to one skilled in the art that various substitutions and modifications may be made to the invention disclosed herein without departing from the scope and spirit of the invention. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, in a preferred embodiment, the drilling rig apparatus  11  of the present invention comprises a duplex drill pipe wrench  13  connected to a wrench holder  15  located on a drilling rig within reach of a mouse-hole  17  and a drill pipe rotator tool  19 . The duplex drill pipe wrench  13  is positionable in three dimension by means of its combination with positionable wrench holder  15 . It is a feature of this embodiment that the positionable wrench holder  15  is located on the drilling rig within reach of and capable of positioning the duplex drill pipe wrench  13  alternatively over both mouse-hole  17  and the vertical axis of well bore rotary table  18 . 
     Referring to FIGS. 2 to  4 , the duplex drill pipe wrench  13  has a set of upper jaws  21  and a set of lower jaws  23  each constructed in a horseshoe-like configuration. Jaw sets  21  and  23  are stacked one upon the other and configured to have a concentric bore  29  (indicated by the + sign), and to have open ends  27  and  25  aligned for receiving, aligning and releaseably engaging the mating ends of two drill pipes (not shown). Receiving and aligning the end coupling of a joint is facilitated by jaw shims  28  and bore shim  30  in each jaw set. Use of appropriate shims allows the axis of different diameter pipe to be aligned concentrically with the bore  29  of wrench  13 . Each set of jaws is hydraulically activated to engage or release the end of a section of drill pipe. 
     In the preferred embodiment, each set of jaws has a first, manually positionable jaw  31  and a second jaw  33  that is hydraulically positionable by activation of a hydraulic piston connected thereto. Jaw  31  is manually positionable by any of a number of means known in the art, including a means selected from the group consisting of: a screw thread, a detent and a lock pin. Alternatively, both jaws could be hydraulically positionable. The jaw sets are reversibly rotatable relative to each other about the axis of the concentric bore by means of a pivoting interface. 
     In the preferred embodiment, one set of jaws is reversibly rotatable relative to the other set of jaws by means of hydraulic torque cylinder assembly  37 , which rotates the stacked jaw sets through about 30 degrees relative to each other. Rotation is centered on the concentric axis  29  of the jaw sets by means of pivoting interface  41 . In the preferred embodiment, pivoting interface  41  is comprised in the lower jaw set  23  of rail-slot  43  and rail-guides, and in the upper jaw set  21  of pivot rail  47 . Additionally, there may be a friction reducing surface  49  attached to one or both sides of the pivoting interface  41 . Housing  39  contains the stacked jaw sets and mounts the controls for operating the wrench. In the preferred embodiment, the lower jaw set  23  is fixed relative to housing  39  and the upper set  21  of the stacked horseshoe configuration is reversibly rotatable relative to lower jaw set  23 . 
     Referring back to FIG. 1, in the preferred embodiment, the positionable wrench holder  15  comprises an upright post  51  mounted on the rig floor, and having an arm  53  with one end connected to the upright post and extending radially outward. It is preferred that the combination of arm  53  attached to post  51  permits rotation of the arm  53  about the vertical axis of post  51 . Additionally, it is preferred that arm  53  be variously positionable through the height of post  51 . Means for either of these latter two preferred features are known and readily accomplishable by one of ordinary skill in the art. The other end of arm  53  is connected to duplex drill pipe wrench  13 . The combined assembly permits the movement and positioning of duplex drill pipe wrench  13  at appropriate locations within the three dimensional reach of wrench holder  15 . In the preferred embodiment, the positionable wrench holder  15  combination of arm  53  and post  51  comprises a crane having tackle  55  for connecting to and suspending the duplex drill pipe wrench  13  from arm  53  at various heights, and tackle  57  means for positioning wrench  13  radially with respect to post  51 . 
     In an alternative preferred embodiment, the arm  53  of positionable wrench holder  15  comprises a track and the duplex drill pipe wrench  13  is mounted on wheels for positioning the wrench radially with respect to the post  51 . It is envisioned that this embodiment be accomplished in at least two ways. First, the track may be suspended low above the floor of the rig, as in the arm of a crane, and the track pivotably positionable around the post. Or the track may rest on the floor of the rig and be pivotably positionable around a turntable. In this latter embodiment, the duplex drill pipe wrench  13  may be mounted on a wheeled carriage, adjustable to vary the height of the wrench  13 . 
     The preferred method of the present invention is to perform the following procedure simultaneously with top drive drilling operations to accomplish maximum efficiency of the top drive drilling operation. The preferred procedure of using the present invention for making up a connection between two individual sections of drill pipe, each section having complementary threaded pin and box couplings at either end involves the steps of: providing a drilling rig mouse-hole  17  with means for rotating a drill pipe  19 . Then a first drill pipe is partially inserted into the mouse-hole  17  and engaged by the mouse-hole rotational tool  19 . The duplex drill pipe wrench  13  is positioned using wrench holder  15  to receive the upper end of the first drill pipe engaged in the rotating mouse-hole tool  19 . The axis of the first drill pipe is aligned with the bore  29  of lower jaw set  23  by means of shims  28  and  30  in the lower jaw, then the jaw is hydraulically actuated to engage the first drill pipe adjacent the upper coupling with the lower jaws  23  of the wrench  13  sufficiently to retain concentric alignment, but not to prevent rotation. 
     Using means known in the art, a second drill pipe is suspended vertically in line with the axis of the first drill pipe, with the complementary or mating coupling of the second drill pipe down and in position to be received, aligned and engaged by the upper jaws  21  of the duplex drill pipe wrench  13 , in a manner analogous to that for the lower the lower jaws  23 . However, engagement of the second pipe joint coupling by the upper jaw set  21  prevents rotation of the second joint. 
     While holding the second joint fixed, and with the first joint free to rotate around its axis, the mouse-hole tool  19  is actuated to rotate the first drill pipe and thread the complementary couplings together. If an axial bias is required to bring the coupling together to initiate threading, it may be supplied by the action of the mouse-hole tool  19 , or accomplished by positioning of wrench  13  by positioner  15 . After the joints are fully threaded together, mouse-hole tool  19  is deactivated. The lower jaw set  23  of duplex drill pipe wrench  13  is readjusted to fixably engage the first drill pipe. Then the connection of the two joints is made up to full torque by activating hydraulic piston  38  of torque assembly  37  to rotate the joints through up to 30 degrees relative to each other. The jaws of wrench  13  are released, and the wrench  13  is removed from the drill pipe. The mouse-hole is made to release the drill pipe, and the drill pipe may be lowered further into the mouse hole and the procedure repeated, or it may be removed from the mouse hole. 
     The breaking out of drill pipe may be accomplished by using substantially the reverse of the make up procedure. 
     While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof. Many other variations are possible, which would be obvious to one skilled in the art. Accordingly, the scope of the invention should be determined by the scope of the appended claims and their legal equivalents, and not just by the embodiments.