Rotary Drilling Head And Method Of Breaking Pipe Joints

Abstract

A rotary driving head for powering a drill string having a splined plunger within its powered spindle which is remotely controlled for selectively rigidly interconnecting the spindle and a joined section of drill pipe so that the latter can be unscrewed from its lower coupling by simply reversing the rotation of the rotary head.

Description

BACKGROUND OF THE INVENTION

This invention relates to rotary driving heads for rotating the bit carried by a string of drill pipe.

Heretofore, in withdrawing drill pipe from a shot hole, for instance, to change the bit, it has been necessary to provide two workmen, or for a single workman to make several trips between his control console and the drilling mast. Furthermore, the use of loose wrenches in holding the pipe for unscrewing, as by a powered tong, has substantially limited the angular disposition of the drill pipe.

Accordingly, an object of the present invention is to provide a novel rotary drilling head which can be operated by a single workman with a substantially reduced number of trips between the control panel and the drilling installation, thus substantially reducing the man hours required in withdrawing the drill string from the hole.

Another object is to eliminate the use of loose wrenches heretofore utilized in withdrawing pipe from the hole, thereby permitting the drilling of a hole at any angle.

SUMMARY OF THE INVENTION

The novel rotary drilling head has a hollow drilling spindle at the free end of which is a box tool joint for threaded attachment to the pin joint at the end of a drill pipe section. Slidable within the interior of the spindle is a fluid-actuated plunger having external splines normally meshing with splineways in the splindle wall and capable, in the advanced position of the plunger, of cooperating with internal splines in the pin joint of a connected pipe section for locking together the spindle and the pipe section whereby reverse rotation of the rotary head will unscrew the pipe section from its lower or remote coupling. Both the control fluid for the plunger and the controls for the spindle powering means are remotely located so that a single operator can withdraw the piping from the hole, including breaking out the tightly made-up joints, with minimum trips from the control position to the drilling installation.

BRIEF DESCRIPTION OF THE DRAWINGS

These objects and others hereafter appearing are attained substantially by the structure illustrated in the accompanying drawings in which

FIG. 1 is a longitudinal section through a rotary drilling head, showing the novel breakout plunger in the advanced position.

FIG. 2 is a section similar to FIG. 1, but showing the breakout plunger in the retracted position.

FIG. 3 is a schematic representation of a rotary driving head in use according to prior art structures and procedures in drilling a shot hole in a mine or quarry.

FIG. 3a shows a separate open wrench used with prior art equipment.

FIG. 3b shows a torquing device also used with the prior art head.

FIGS. 4, 5, and 6 are similar schematic views illustrating the simplified procedure in withdrawing a drill string from the hole, utilizing the novel rotary drilling head

FIG. 4 a is a plan view of the pipe clamp.

DETAILED DESCRIPTION OF THE DRAWINGS

The novel rotary drilling head as shown in FIGS. 1 and 2 consists of a hollow casing 8 having apertured lugs 9 and 10 projecting sidewardly thereof for mounting on a suitable mast or support along which the rotary head may be propelled to insert the drill pipe and bit into the hole and remove the same therefrom, as explained hereafter. At the rear end of casing 8 there is mounted the gear housing 11, enclosing a planetary gear system 12. A powering motor 13, usually fluid driven, is mounted on housing 11. Drive shaft 14 interconnects the gearing with a drive spindle 15 having an internal chamber 16 and rearwardly mounted in bearings 17. Drive shaft 14 is nonrotatably connected to spindle counterbore 18 by rectangular and cylindrical keys 19 and 20 and an intervening bushing 21. Gear housing 11 is secured to casing 8 by bolts 22.

The front end of casing 8 is closed by a cap 23 secured to casing 8 by cap screws 24 and including a forwardly projecting neck 25 incorporating seal packings 26, 27, and 28 between the same and spindle 15. An O-ring seal 29 is inserted between cap 23 and casing 8. Porting 30 in the casing connects pressured fluid piping 31 from a control valve (not shown) to an annulus 32 in cap 23. Other ports 33 connect the annulus to the forward portion 48 of spindle chamber 16.

A plunger 34 is slidable longitudinally within the chamber 16 of spindle 15 and is constantly urged rearwardly by a coiled compression spring 35 seated at its left end against a guide and spring seat collar 36 having internal splineways 37 and secured in position at the left end of the spindle chamber by means of a pen 38. The plunger has a forwardly extending stem or shank 39 provided with splines 40 which slide in complementary internal splineways 37 in guide collar 36. A female or box tool joint 42 is formed at the forward end of spindle 15 and has the usual tapered threads for meshing with complementary threads on a male or pin tool joint 43, as at 44. Pin joint 43 is welded, as at 45, to the end of drill pipe 46, and has internal splineways 47 for meshing with plunger splines 40 in the advanced position of the plunger (FIG. 1), as will be explained. Tubing 50 connects pressured fluid from a control valve (not shown) through a port 51 to an annulus 52, thence through ports 53 to spindle chamber 16.

Control fluid tubing 50, drilling fluid line 31, and the operating lines (not shown) for motor 13, and the pipe clamping device (FIG. 4) lead to controls conveniently located for the operator, as on a common panel which may be at some distance from the drill. FIG. 1 shows the novel breakout plunger 34 advanced into the coupled pin joint 43 for locking together spindle 15 and drill pipe 46. This action of the plunger is produced by the supply of pressured control fluid through piping 50. FIG. 2 shows plunger 34 fully retracted within spindle chamber 16 by expansion of compression spring 35 upon cutoff of control pressure in pipe 50 and exhausting of chamber 16.

In order to emphasize the advantages of the novel rotary drilling head, FIG. 3 illustrates, schematically, the conventional prior art equipment used in drilling a hole through rock, for instance, a shot hole, and withdrawing the drill string from the hole, as at the end of drilling or to replace a bit. At 56 there is represented a conventional rotary drilling head which is slidably carried on a mast or other support 57 having a base ledge 58. A drill pipe 59 is shown depending into the borehole 60. Lower drill pipe section 59 and upper drill pipe section 61 are provided with conventional threaded pin and box tool joints, respectively, at their upper and lower ends, while drive spindle 62 depending from the rotary head is provided with a threaded box joint for coupling to the pin joint at the upper end of pipe 61. These couplings are represented by lines 54 and 55. Conventionally, the tool joints on these drill pipes are provided with opposite wrench recesses or flats as at 63, 64, and 65. A loose or separate pipeholding wrench is indicated at 66. A powered pipe torquing device is shown at 67. Mechanism for moving head 56 along mast 57 is represented by a cable 72 encompassing pulleys 73 and 74 on mast 57 and connected at its ends to head 56. A drive motor for the cable is shown at 75. controls for fluid lines 56a for rotary drilling head 56 as well as the mechanism for lowering or advancing and lifting or withdrawing the pipe string and torquing device 67 are located conveniently for the operator and usually away from the mast.

FIGS. 4, 5, and 6 schematically represent equipment used with the novel rotary drilling head in inserting and withdrawing drill pipe into and from the borehole. Rotary head 80 is slidably supported on a suitable mast or frame 81, with base ledge 81a, for movements therealong by suitable means, as at 72, 73, 74, 75 in FIG. 3. A powered pipe gripping device 82 mounted on the frame slightly above ledge 81a, has jaws 83 and 84 pivotally connected at 85 and urged together to grip a pipe between serrated faces 86 and apart to release the pipe by a fluid motor 87. The tool joint connection between spindle 42 and pipe 88 is represented by line 89 and the joint between pipes 88 and 90, the latter entering borehole 91 is represented at 92. No wrench flats or other special configurations are provided on the tool joints.

Operation of Prior Art

In using the prior art equipment (FIG. 3) in removing pipe from the borehole, the operator, in control position, moves the upper pipe section 61 wholly above borehole 60 so as to expose the upper joint 54 between spindle 62 and section 61 as well as lower joint 55 between pipe sections 61 and 59. He now walks from his control position to the mast and places an open-end wrench, as 66, FIG. 3a, in the upper wrench flats 63 of lower drill pipe 59 and resting on base ledge 58 on mast 57. This wrench is used to hold pipe 59 against rotation and also serves to keep the pipe string from falling back into the hole. The operator walks (second time) to the controls and rotates spindle 62 a small amount so that the handle of wrench 66 will abut mast 57. He also moves a pipe torquing device 67 to a position adjacent pipe 61 just above or below wrench flats 64 therein. He then must again walk (third trip) to the mast and manipulate device 67 so as to lock onto pipe 61. Now he again walks (fourth trip) to the control panel and actuates a hydraulic so as to apply torque to pipe 61 and thereby break lower joint 55. He again walks to the mast (fifth trip), removes the hydraulic torque device 67 from pipe 61 and places a wrench, as 66, on the lower wrench flats 64 of drill pipe 61. He then returns to the control panel (sixth trip) and rotates head 56 reversely to first cause the wrench to strike the mast and, thereafter, reverse rotation to loosen the coupling 54. After both couplings 55 and 54 are fully unthreaded, the operator finally returns to the mast (seventh trip) to remove pipe 61.

Next, through the control panel (eighth trip) he lowers head 56 and rotates the spindle in the foward direction to threadedly couple the spindle to lower pipe 59, stopping such coupling rotation somewhat before the threads are fully engaged. He then repeats the cycle.

Operation of the Improved Rotary Head

In use of the novel rotary head 80 to withdraw a pipe string from a borehole, with reference to schematic FIG. 4, 5, and 6, rotary head 80 with upper pipe section 88 tightly secured to spindle 42, is elevated to the position of FIG. 4. However, lower tool joint 92 need not be exposed. With the operator in his control position, cylinder 87 (FIG. 4a) is pressured to clamp jaws 83, 84 tightly about pipe 88. Rotary head 80 and spindle 42 are then reversely operated a slight amount, say approximately 180 degrees, to breakout tool joint 89. Cylinder 87 is now actuated to open jaws 83, 84 and release pipe 88, the pipe string is elevated to the position of FIG. 5 with coupling 92 above jaws 83, 84, and device 82 is again actuated to grip lower pipe section 90. Breakout plunger 34 in the rotary head is then actuated forwardly to directly connect spindle 42 to pipe 88. The spindle is then reversed to breakout tool joint 92 between drill pipes 88 and 90. The breakout piston is then retracted and the reverse rotation of the spindle is continued until both tool joints 89 and 92 are completely unscrewed. The rotating head is then moved upwardly or back sufficient to release pipe 88 which is then removed by the operator. Note this is the first time the operator need move from his control station to the mast. Rotary head 80 is lowered and then rotated forwardly for loose attachment to the upper end of pipe 90 (coupling 89a) preparatory to breaking out and removal of the next pipe section.

Thus, the number of trips of the operator between his control station and the mast in an operative cycle breaking out and removing each pipe section is reduced from the eight required in the prior art procedure, as described above, to one trip with the use of the novel rotary head and a cooperating powered clamping device. Accordingly, the number of man hours utilized and the resulting cost in withdrawing a drill string from the borehole are correspondingly reduced. Furthermore, no loose wrenches are used, so that the mast and drill string can be utilized at any angle for drilling a borehole. Also, the exterior of the tool joints remains smoothly cylindrical, no exterior configurations for wrenches and torquing tools being required, thus reducing wear due to contact with the bore wall, since the splining for accomodating the breakout plunger is located in the protected inner walls of the tool joints. The roatry head, except for the novel breakout means, and the supporting mast arrangement, may be modified as will occur to those skilled in the art. Exclusive use of all modifications as will occur to those skilled in the art is contemplated.

Claims

We claim:

1. A rotary driving head for a drill string comprising a casing, a drive spindle projecting therefrom, coupling means rotatable with said spindle for attachment to complementary coupling means on the end of a drill pipe, plunger means movable along said spindle, torque applying means on said plunger means for cooperating with complementary torque receiving means on the drill pipe coupling means, and means for shifting said plunger means between a retracted position clear of said coupling means and an advanced position projecting into said coupling means for locking said coupling means together.

2. A rotary driving head as described in claim 1 in which said spindle has a threaded coupling at its free end for attachment to a threaded complementary coupling on a drill pipe.

3. A rotary driving head as described in claim 1 in which said spindle is hollow and said plunger is slidable within said spindle.

4. A rotary driving head as described in claim 3 further including means for applying pressured fluid to said plunger for actuating the same to and from its retracted and advanced positions.

5. A rotary driving head as described in claim 3 in which said torque applying means comprise splines on said plunger.

6. A rotary driving head as described in claim 4 further including spring means for actuating said plunger in one direction and a control for said pressured fluid for selectively actuating said plunger in the other direction.

7. A rotary driving head for a drill string comprising a casing and powering means, a hollow drive spindle projecting forwardly from said casing and having an internal chamber and a tool joint at its forward end, an internally splined guide sleeve in the forward portion of said chamber, an externally splined plunger reciprocable in said spindle chamber from a retracted position wholly within said chamber to an extended position projecting forwardly of said chamber for cooperating with a complementarily splined pipe coupling to secure said spindle and said coupling against relative rotation.

8. A rotary driving head as described in claim 7 in combination with a complementary tool joint threadedly coupled to said joint with internal splines for mating with the splined plunger in the advanced position thereof.

9. A rotary driving head as described in claim 7 in combination with support means movably mounting said head and a remotely controlled pipe gripping device for application to a pipe string on the side of a joint to be broken opposite to said rotary head.

10. The method of breaking a pipe joint in a drill pipe string threadedly attached to the drive spindle of a rotary drilling head movably mounted on a mast and of the type in which the spindle carries a member movable between a retracted position within the spindle and an advanced position securing the spindle and an attached pipe against relative rotary movement, including the steps of

a. locking the pipe string on the side of the joint to be broken opposite to the rotary head,

b. advancing said member into the attached pipe to lock said spindle and pipe against relative movements, and

c. reversely actuating said head and spindle to unscrew the spindle attached pipe section at said joint.