Horizontal boring pipe connecting and disconnecting device

Abstract

Apparatus and methods, for making and breaking connections in a horizontal boring drillstring, comprising a skid-mounted torque wrench and a spinning unit hydraulically operated from a remote control station, therefore allowing a coupling to be made or broken without manual intervention. One embodiment of a preferred torque wrench and spinning unit is horizontally mounted on a structural frame that is adapted to allow movement relative to a horizontal drill string. A preferred torque wrench comprises a gripping mechanism that serves to hold stationary one half of a coupling and a torquing mechanism that arcuately translates the adjoining half of the coupling to either make-up or break-out the coupling. A preferred spinning unit comprises a plurality of drive rollers that impart rotational motion into the pipe to engage or disengage the threads of a coupling.

Description

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.

FIELD OF THE INVENTION

[0003] This invention relates generally to underground boring. More particularly, this invention relates to methods and apparatus for making and breaking threaded connections between pipe segments that are used in underground boring. Still more particularly, the present invention relates to making and breaking threaded connections at the pipe end of a horizontal borehole.

BACKGROUND OF THE INVENTION

[0004] Utility lines for water, electricity, gas, telephone and cable television are often run underground for reasons of safety and aesthetics. In many situations, the underground utilities can be buried in a trench which is then back-filled. Although useful in areas of new construction, the burial of utilities in a trench in developed areas may result in disturbance to existing structures, roadways, and utilities. As a partial solution, the general technique of boring a horizontal underground hole has been developed in order to overcome some of the disadvantages of conventional trenching techniques.

[0005] In accordance with such a general horizontal boring technique, also known as microtunnelling, horizontal directional drilling (HDD) or trenchless underground boring, a boring system is situated on the ground surface and drills a hole into the ground at an oblique angle with respect to the ground surface. The hole is normally drilled by rotating a drill bit that is attached to the end of a length of hollow pipe. As the depth and length of the hole increases, additional lengths of pipe are attached and fed into the hole. The assembly of the multiple lengths of pipe and the drill bit is known as a drill string. A drilling fluid is typically flowed through the drill string, over the bit, and back up the borehole in order to remove cuttings and dirt.

[0006] After the drill reaches a desired depth, the tool is then directed along a substantially horizontal path to create a horizontal borehole. Once the desired horizontal borehole is drilled, the drill string then drills through to the surface. The location at which the pipe breaks the surface is referred to as the “pipe end” of the hole, while the end from which the hole is drilled is known as the “drill end.” At the pipe end, a reamer may be attached to the drill string and pulled back through the borehole, thus reaming out the borehole to a larger diameter. It is also common to attach a utility line or other conduit to the reaming tool so that it is dragged through the borehole along with the reamer. When installing a reamer, or for other applications, it is sometimes desirable to be able to break-out individual lengths of drill pipe from the pipe end of the hole.

[0007] Drill strings may comprise many individual lengths of pipe, each of which is connected in series to form the drill string. The joints between lengths of pipe are often threaded connections that must be torqued to within set limits in order to prevent failure of the connection or damage to the thread. In most prior art boring applications, the individual lengths of pipe are positioned in place and connected to the drill sting manually. Manually making and breaking these pipe connections not only takes a long time but is potentially hazardous to personnel using the equipment.

[0008] In vertical drilling applications, such as those used to drill hydrocarbon wells, this safety and efficiency problem has been addressed by mechanisms designed to connect and disconnect lengths of vertical drill pipe. One such mechanism is disclosed in U.S. Pat. No. 4,348,920, issued to Boyadjieff. Boyadjieff discloses is what has become known as an iron roughneck, or automatic roughneck. These devices generally comprise a large structure mounted on rails that allow the structure to move from a remote position to a position centered on a drill string. Once a new length of drill pipe is placed in position over the drill string, the iron roughneck is moved into position. An iron roughneck generally comprises a spinning mechanism that grasps the new drill pipe and rotates it until the connection is initially made-up. Iron roughnecks also have a torquing mechanism that imparts the required amount of torque into the threaded connection. Most iron roughnecks can also be used to disconnect the lengths of drill pipe.

[0009] Horizontal drilling units, such as are described in U.S. Pat. No. 5,231,899, issued to Lee, also have been designed with components that are used to make-up and break-out lengths of drill pipe from the drill end of the hole. Lee describes a rotary drill rig, mounted on a frame and having a moveable carriage with a rotary motor. The rig also has one wrench for holding pipe in place and second wrench fitted with a hydraulic cylinder for applying torque to make or break connections. As new pipe joints are added or removed, the wrenches are used to make or break the connections and the rotary motor, which also provides drilling torque, engages or disengages the connection threads.

[0010] There are no devices currently being used to automate the process of connecting and disconnecting lengths of pipe used in horizontal boring operations at the pipe end of the hole. Therefore, there remains a need in the art to develop a device which will make and break threaded connections used in these types of operations. The present invention is directed to methods and apparatus for making and breaking connections between pipes used in horizontal boring operations.

SUMMARY OF THE PREFERRED EMBODIMENTS

[0011] Accordingly, there is provided herein methods and apparatus for making and breaking connections in a drillstring used in horizontal boring operations. One embodiment of the present invention comprises a torque wrench and a spinning unit that operate to fully engage and disengage a coupling in a horizontal drill string. A preferred torque wrench and spinning unit is hydraulically operated from a remote control station, therefore allowing a coupling to be made or broken without manual intervention.

[0012] One embodiment of a preferred torque wrench and spinning unit is horizontally mounted on a structural frame that is adapted to allow movement relative to a horizontal, or near horizontal, drill string. A preferred torque wrench comprises a stationary gripping mechanism and a rotating torquing mechanism, wherein the gripping mechanism serves to hold stationary one half of a coupling while the torquing mechanism arcuately translates the adjoining half of the coupling to either make-up or break-out the coupling. A preferred spinning unit comprises a plurality of drive rollers that impart rotational motion into the pipe in order to engage or disengage the threads of a coupling. Both the torquing mechanism and the spinning unit preferably are adapted to receive pipe sections either along the axis of the drill string or in a direction perpendicular to that axis.

[0013] In one preferred method of operation, the torquing mechanism and spinning unit are opened to accept the end of the drill string. The gripping portion of the torquing mechanism grasps the drill string on the coupling to be broken. The torquing mechanism is then actuated until the coupling begins to turn. The gripping and torquing mechanisms are then released and the spinning unit is activated in order to disengage the threaded coupling of the pipe joint from the mating coupling on the drill string. The spinning unit rotates the pipe joint about the axis of the coupling until the thread is fully disengaged. Once the thread is fully disengaged, the pipe joint can be removed and stored until needed. All of the above described steps are preferably executed without manual intervention in the torquing or spinning process. The operation can be controlled from a remote control station. The above described method can also be used to makeup a pipe joint by reversing the process.

[0014] Thus, the present invention comprises a combination of methods and apparatus that enable a pipe joint to be made-up or broken-out of a horizontal drill string without manual intervention from an operator. Thus, the present invention increases safety by removing personnel from the process and improves the process by providing a consistent level of torque applied to the couplings. These and various other characteristics and advantages of the present invention will be readily apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments of the invention and by referring to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] For a more detailed understanding of the preferred embodiments, reference is made to the accompanying Figures, wherein:

[0016] FIG. 1 is an elevation view of one embodiment of a combination torque wrench and spinner assembly;

[0017] FIG. 2 is an elevation view of one embodiment of a torque unit;

[0018] FIG. 3 is an elevation view of one embodiment of a torque unit; and

[0019] FIG. 4 is an elevation view of one embodiment of a spinner unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] In the description that follows, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness.

[0021] The present invention relates to methods and apparatus for making and breaking pipe couplings in a horizontal drill string. The present invention is susceptible to embodiments of different forms. There are shown in the drawings, and herein will be described in detail, specific embodiments of the present invention with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein. In particular, the following description of a method of employment will involve using embodiments of the present invention to remove joints of pipe from the drill string at the pipe end of the hole, but the embodiments of the present invention can also be used to add lengths of pipe at the drill end. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results.

[0022] Referring now to FIG. 1, an elevation of an assembly 10 comprises a torque unit 14 and a spinning unit 16, each of which are slidably mounted to a skid 12. Skid 12 has a rails 30, 32 on which torque unit 14 and spinning unit 16 are slidably engaged. Torque unit 14 can be moved along rails 30 by extending or retracting hydraulic cylinder 26. Spinning unit 16 can be moved along rails 30 by extending or retracting hydraulic cylinder 28. Wheels 34, attached to torque unit 14 and spinning unit 16 on rails 30.

[0023] Torque unit 14 is preferably capable of imparting a required torque into a coupling, either to make or break the connection. Torque unit 14 is preferably mounted to a chassis 18 that supports the unit and provides for lateral movement in relation to skid 12. This movement allows torque unit 16 to be adjusted to properly align with a coupling. Torque unit 16 is also preferably capable of acting in a clockwise or counter-clockwise direction. A preferred torque unit 16 is actuated and controlled by a hydraulic system.

[0024] FIG. 2 generally illustrates the structure of one embodiment of a torque unit 14 including a rotating gripping assembly 22 adapted to grip and apply torque in either direction to one half of a pipe coupling, and a stationary gripping assembly 20 adapted to engage and maintain stationary the other half of a coupling. Each gripping assembly 20, 22 comprises gate 54 pivoted to body 64 for movement between an open position passing the pipe into engagement with the gripping assembly and a closed position to securely grip the pipe within the assembly. Gate 54 may be held in closed position by a latch element (not shown) and is preferably moved between the open and closed position by hydraulic actuators (not shown). Once gate 54 is closed, gripping elements 66, carried by gate 54, and diametrically opposed gripping elements 68, mounted to piston 56, act to tightly grip the pipe when pressurized fluid is forced into a cylinder chamber (not shown) to move piston 56 toward the center of pipe 40.

[0025] As shown in FIG. 3, after first and second gripping assemblies 20, 22 have been actuated to tightly grip pipe 40 on either side of a threaded connection, the assembly 22 is rotated relative to pipe 40 and assembly 20 to either break the threaded connection or make it up to a tightened condition. This relative rotation is produced by two piston and cylinder mechanisms 58, each of which has its cylinder connected to one of assemblies 20, 22 by a pivoting arm 60, 62. The pressure acting on piston and cylinder mechanisms 58 can be controlled to limit the amount of torque that is applied to the coupling during actuation.

[0026] Spinning unit 16 serves to rotate a joint of pipe in order to engage or disengage a threaded connection. A preferred spinning unit 16 provides a recess into which a pipe is received for powered rotation by the spinning unit. A preferred spinning unit 16 is also mounted for lateral movement relative to skid 12 so that the location of the interface between a pipe joint and the unit can be controlled and to adjust for movement of the pipe joint as a coupling is engaged or disengaged.

[0027] FIG. 4 generally illustrates the structure of one embodiment of spinning unit 16, comprising spinning mechanism 24 and side plates 36 mounted to a frame 22. Spinning mechanism 24 comprises gear system 42 that is rotated by a motor (not shown) and rotates pipe 40 in either a clockwise or counter-clockwise direction. Gear system 42 is raised and lowered by hydraulic cylinder 44 to maintain the desired contact with pipe 40. Spinning mechanism 24 also comprises a pair of retaining arms 48 that rotate about pin 50 to maintain roller 52 in contact with pipe 40. The position of arm 48 is controlled by extending and retracting hydraulic cylinder 46 and preferably can be adjusted so that arms 48 are in a fully open position to allow pipe 40 to be lifted from spinning unit 16. Spinning unit 16 may be any type of mechanism used to rotate pipe. Spinning unit 16 is preferably able to rotate in both a clockwise and counter-clockwise direction and be hydraulically powered.

[0028] Referring back to FIG. 1, during horizontal boring operations, a site is prepared to receive the drill string as it rises to the surface. Torque wrench and spinner assembly 10 is positioned to align with the drill string as it exits the formation. Assembly 10, preferably mounted on skid 12, may be positioned on the surface, truck-mounted, or set into a trench dug into the ground. Assembly 10 may be horizontal or placed at an angle to receive the drill string. Assembly 10 is preferably placed so that pipe coming out of the hole first encounters torque unit 14. Torque unit 14 and spinning unit 16 may be fully opened so that the drill string can be lowered into the units from above. The drill string may also be inserted axially through torque unit 14 and spinning unit 16.

[0029] The drill string is positioned, and torque unit 14 adjusted, so that a pipe coupling is properly engaged with the torque unit. Torque unit 14 applies a torque to the coupling to break the connection. Torque unit 14 is then released so that spinning unit 16 can be actuated to rotate the free end of the drill string in order to disengage the coupling. Once the coupling is fully disengaged the pipe joint can be removed. Assembly 10 preferably works in conjunction with a crane, or other lifting apparatus, to safely manipulate the pipe joint after removal from the drill string. This same process can be reversed to add pipe back to the drill string.

[0030] All of the functions of both the torque unit 14 and spinning unit 16 are preferably hydraulically actuated from a control panel that is remote from assembly 10. Functions may be individually controlled or operate as part of a single hydraulic circuit. The use of hydraulic power also serves to control the amount of torque applied to a coupling so as to ensure consistent, correct connection strengths without risk of damage to the coupling.

[0031] Therefore, the above described assembly allows joints of pipe to be removed from, or added to, a horizontal drill string exiting the ground at the pipe end of a borehole. By providing a remotely operated hydraulic assembly, a single operator can make and break pipe connections safely from a remote location. Furthermore, the use of a hydraulic system allows precise control of the torque applied to a coupling so that damage to the coupling can be limited.

[0032] The embodiments set forth herein are merely illustrative and do not limit the scope of the invention or the details therein. It will be appreciated that many other modifications and improvements to the disclosure herein may be made without departing from the scope of the invention or the inventive concepts herein disclosed. Because many varying and different embodiments may be made within the scope of the inventive concept herein taught, including equivalent structures or materials hereafter thought of, and because many modifications may be made in the embodiments herein detailed in accordance with the descriptive requirements of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.

Claims

1. An apparatus for handling a horizontal boring drill string formed by a plurality of pipe joints joined by couplings, the apparatus comprising; a skid oriented along the axis of the horizontal boring drill string; a torque unit mounted to said skid; and a spinning unit mounted to said skid, wherein said torque unit and said spinning unit are adapted to make or break couplings in the horizontal boring drilling string.

2. The apparatus of claim 1 wherein said torque unit and spinning unit are adapted to move relative to said skid in a direction parallel to the horizontal boring drilling string.

3. The apparatus of claim 1 further comprising a remote control station adapted to control said torque unit and said spinning unit from a remote location.

4. The apparatus of claim 1 wherein said torque unit further comprises: a stationary gripping mechanism adapted to grip and hold stationary a first portion of a coupling; and a rotating torquing mechanism adapted to grip and rotate a second portion of the coupling.

5. The apparatus of claim 1 wherein said spinning unit further comprises a plurality of drive rollers adapted to impart rotational motion onto a pipe joint.

6. The apparatus of claim 1 wherein said torque unit and said spinning unit are adapted to receive individual pipe joints in a direction perpendicular to the axis of the drilling string.

7. A method of removing sections of pipe from a horizontal drill string at the pipe end of a horizontal borehole, said method comprising: gripping the horizontal drill string with a hydraulically actuated torquing mechanism mounted to a skid; applying a torque to a coupling in the drill string with the torquing mechanism; activating a hydraulic spinning unit to disengage the coupling such that a section of pipe is separated from the drill string.

8. The method of claim 7 further comprising releasing the torquing mechanism before activating the hydraulic spinning mechanism.

9. The method of claim 7 further comprising: opening the torquing mechanism and the spinning unit; and removing the separated section of pipe from the torquing mechanism and the spinning unit in a direction perpendicular to the axis of the drill string.

10. The method of claim 7 wherein hydraulic force is used to apply torque to the coupling.

11. The method of claim 7 wherein the torquing mechanism and the spinning unit are operated from a remote control station.

12. A pipe handling apparatus comprising: a skid aligned with the axis of a horizontal drill string including a series of pipe joints connected by threaded couplings; means for applying torque to a coupling to make or break the threaded connection; and means for rotating a pipe joint that is separate from the drill string so as to engage or disengage the threaded coupling.

13. The apparatus of claim 13 wherein said means for applying torque comprises: means for gripping and holding stationary a first end of a coupling; and means for applying torque to a second end of the coupling.

14. The apparatus of claim 12 further comprising means for controlling the apparatus from a remote location.

15. The apparatus of claim 12 further comprising means for allowing pipe joints that are separate from the drill string to be moved in a direction perpendicular to the axis of the drill string.

16. The apparatus of claim 12 wherein said means for applying torque is hydraulically actuated.

17. The apparatus of claim 12 wherein said means for rotating is hydraulically actuated.

18. The apparatus of claim 12 wherein said means for applying torque and said means for rotating are adapted to move along said skid in a direction parallel to the axis of the drill string.