U.S. patent application number 11/305607 was filed with the patent office on 2007-06-21 for combined directional and impact drilling motor.
Invention is credited to Duane H. Bennett, Jerry Foster, Michael P. Sanders.
Application Number | 20070137897 11/305607 |
Document ID | / |
Family ID | 38172113 |
Filed Date | 2007-06-21 |
United States Patent
Application |
20070137897 |
Kind Code |
A1 |
Sanders; Michael P. ; et
al. |
June 21, 2007 |
Combined directional and impact drilling motor
Abstract
A directional drilling mechanism is disclosed. The mechanism is
also an impact drill.
Inventors: |
Sanders; Michael P.;
(Lexington, KY) ; Foster; Jerry; (Richmond,
KY) ; Bennett; Duane H.; (Brookside, KY) |
Correspondence
Address: |
STOCKWELL & SMEDLEY, PSC
861 CORPORATE DRIVE, SUITE 200
LEXINGTON
KY
40503
US
|
Family ID: |
38172113 |
Appl. No.: |
11/305607 |
Filed: |
December 16, 2005 |
Current U.S.
Class: |
175/61 ;
175/73 |
Current CPC
Class: |
E21B 4/14 20130101; E21B
7/04 20130101; E21B 7/067 20130101; E21B 6/06 20130101 |
Class at
Publication: |
175/061 ;
175/073 |
International
Class: |
E21B 7/04 20060101
E21B007/04 |
Claims
1. A directional and rotating drill mechanism, comprising: an air
compressor, for providing pneumatic energy to said mechanism; a
motor assembly, for rotatably driving a hammer which in turn
rotatably contacts a wellbore area to be drilled, wherein said
motor assembly uses pneumatic energy provided by said air
compressor; a bent sub assembly, connected to motor assembly; for
controllably providing change in direction of said drill; and a
bottom assembly, connected to said bent sub assembly, for linearly
driving and controlling said hammer, wherein said bottom assembly
uses pneumatic energy provided by said air compressor; wherein said
motor, bent sub, and bottom assemblies are connected together in a
drill string.
2. The mechanism of claim 1, further comprising: said hammer having
buttons positioned on its surface; said hammer reciprocates within
a portion of said bottom assembly so as to contact said area with
repeated linear blows, wherein said mechanism simultaneously
imparts rotation to said hammer so that said buttons on the hammer
do not repeatedly strike the same area of said wellbore.
3. The mechanism of claim 1, further comprising: said drill string
is controlled from above ground using a drill pipe.
4. The mechanism of claim 1, further comprising: said drill string
rotates the entire hammer drill in rotations per minute similar to
rotations supplied by the drilling rig and drill pipe, the buttons
to rotate across the entire face of said borehole.
5. The mechanism of claim 1, further comprising: said drill string
is supplied sufficient torque energy by said air compressor to
overcome the drag on the hammer from the sides of the borehole that
hamper rotation.
6. The mechanism of claim 1, further comprising: a motor inside
said motor assembly is sufficiently small to fit inside the tube of
the drill string.
7. The mechanism of claim 1, further comprising: said motor, bent
sub, and bottom assemblies are joined using threaded
connectors.
8. The mechanism of claim 1, further comprising: said joining
occurs using sufficient torque so as to keep the drill string from
disassembling during use.
9. The mechanism of claim 1, further comprising: said drill string
can withstand tensional forces encountered during the drilling
process.
10. The mechanism of claim 7, further comprising: said connectors
provide a tight seal for routing the air necessary to drive the
hammer.
11. The mechanism of claim 1, further comprising: an auxiliary
compressor to assists said air compressor.
12. The mechanism of claim 1, wherein said bottom assembly further
comprises: a regulator to limit the air pressure of the compressed
air before it gets to the vane motor.
13. The mechanism of claim 6, further comprising: an air regulator,
connected between said air compressor and said motor, so that the
air pressure from said compressor is regulated so as to not
overdrive said motor, yet still provides optimum pressure for said
motor to function.
14. The mechanism of claim 6, further comprising: said motor has
fins that turn like the blades of a fan or turbine.
15. The mechanism of claim 1, further comprising: motor assembly
has check valves which are the ports where the air is exhausted out
from said vane motor to the well bore.
16. The mechanism of claim 15, further comprising: said check
valves keep fluids and cuttings from entering the interior of said
drill string when air is not being exhausted.
17. The mechanism of claim 15, further comprising: said check
valves are one-way so as to prevent drilled materials from flowing
back into said drill string.
18. The mechanism of claim 13, further comprising: said regulator
ensures that a specific, fixed amount of pressure arrives at the
motor.
19. The mechanism of claim 13, further comprising: an air filter,
connected between said compressor and said regulator, for
preserving said motor.
20. The mechanism of claim 19, further comprising: said filter
removes all coarse material typically found in compressed air
streams found on drilling rigs.
21. The mechanism of claim 6, further comprising: motor must be
small enough to fit inside the tube of the motor assembly, and also
allow space for air tubing to be placed alongside the motor.
22. The mechanism of claim 21, further comprising: said tubing
allows a supply of air from said air compressor to be not directed
at the motor and instead be supplied to said hammer.
23. The mechanism of claim 1, further comprising: said motor
assembly contains threaded plugs for lubrication.
24. The mechanism of claim 1, further comprising: a gear system for
transforming pneumatic energy into rotational; located within said
motor assembly.
25. The mechanism of claim 24, wherein said gear system further
comprises: a planetary gear system having a sun pinion gear at its
center, surrounded by planet gears; and a top gear hub and a gear
hub base hold the planet gears in place with the proper alignment,
so that they have optimum contact with the sun pinion gear.
26. The mechanism of claim 1, wherein said bent sub assembly
further comprises: two universal joints which act as two different
independent links with another shaft in between the two so that
they turn smoothly.
27. The mechanism of claim 26, further comprising: said bent sub
assembly can be built with a specific angle bend, measured in
degrees.
28. The mechanism of claim 27, further comprising: said bent or
sloped area can be built with a variety of slopes or bends.
29. The mechanism of claim 1, further comprising: a bearing
supported drive shaft to a box coupling for which said hammer can
be attached; wherein said drive shaft is attached to said threaded
housing using shaft pins.
30. The mechanism of claim 29, further comprising: a plurality of
pins secure the box to bearing supported drive shaft under normal
and occasionally high tension loads.
31. The mechanism of claim 30, further comprising: a plurality of
keyways and keys are placed perpendicular to said pins to impart
torque from the drive shaft to the box.
32. The mechanism of claim 1, further comprising: an optional
stabilizer, located within said bottom assembly, which keeps said
drill string centered in the wellbore and keeps side load off said
hammer.
33. The mechanism of claim 29, further comprising: said drive shaft
is centered within the bearing housing by means of tapered roller
bearings.
34. The mechanism of claim 29, further comprising: said box
coupling transfers thrust loads from the hammer to a plurality of
tapered roller bearings, which can withstand take both axial and
radial loads.
35. The mechanism of claim 29, further comprising: said drive shaft
and box coupling is secured within the bottom assembly by means of
retaining rings.
36. The mechanism of claim 22, further comprising: motor assembly
has flutes cut laterally along its length to allow for said tubing
containing bypass air to reach the bent sub assembly.
37. A method of performing directional drilling, comprising:
providing pneumatic power to a drill string using a single power
source; applying a hammer attached to said drill string within a
well shaft in a linear path using said pneumatic power; and
simultaneously rotating said hammer using said pneumatic power.
Description
FIELD OF THE INVENTION
[0001] This invention relates generally to directional drilling,
and more specifically to directional drilling with air hammer
drilling tools or non impact drill bits used in air drilling.
BACKGROUND OF THE INVENTION
[0002] Currently, underground directional drilling has been largely
limited to drilling with roller cone or polycrystalline diamond
compound (PDC) type bits with mud or air-mist rotary drilling
motors utilizing rotor-stator or similar technologies. These
technologies use liquid based drilling fluids. Large portions of
the drilling industry use air hammer drilling tools also known as
drill hammers for conventional straight-hole drilling that strictly
use air as the drilling medium. However, rotor-stator technology is
not suitable or too expensive for air hammer drilling tools.
Consequently, the air hammer drilling industry has had limited
access to the benefits of directional drilling.
SUMMARY OF THE INVENTION
[0003] It is an object of the present invention to provide an
underground directional drilling mechanism that allows standard air
hammer drilling tools to be utilized in the directional drilling
process by the rotating a drill hammer during the impact process
without rotating the drill string. These and other objects and
advantages of the invention will become readily apparent as the
following description is read in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a perspective view of an exemplary embodiment of
the present invention;
[0005] FIG. 2 shows three primary components of the embodiment
shown in FIG. 1;
[0006] FIGS. 3A and 3B shows detail of the motor assembly of the
embodiment shown in FIGS. 1 and 2;
[0007] FIG. 4 shows detail of the bent sub assembly of the
embodiment shown in FIG. 1;
[0008] FIG. 5 shows detail of the bottom bearing assembly of the
embodiment shown in FIG. 1;
[0009] FIG. 6 shows a drill path used by the present invention;
[0010] FIG. 7 shows the motor assembly cut along the lines A-A of
FIG. 3; and
[0011] FIG. 8 shows a retaining ring cut along the lines B-B of
FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] Before explaining the disclosed embodiment of the present
invention in detail it is to be understood that the invention is
not limited in its application to the details of the particular
arrangement shown, since the invention is capable of other
embodiments. Also, the terminology used herein is for the purpose
of description and not of limitation.
[0013] The present invention uses standard air hammer drilling
tools and utilizes them in the directional drilling process.
Existing hammer tools can be used without modification. In
addition, the present invention generates enough torque to use
conventional drill bits in some applications. The present invention
achieves this by operating a drilling motor rotation device that
uses compressed air from an above-ground compressor to rotate
down-hole percussive or hammer drills in oil and gas well drilling,
or other down-hole drilling applications.
[0014] As will be shown in more detail below, the present invention
incorporates a commercially available vane-type pneumatic air
motor, a planetary gear box including a single-piece stem pinion
gear made from hardened steel, and multiple universal joints, among
other features. The entire device is attached to the bottom of the
drill-string (thus below-ground).
[0015] The present invention performs directional drilling by
rotating a down-hole percussive hammer drill without rotating the
cylinder housing or drill string. It also uses an air driven motor
mounted within the device that receives power from above-ground air
compressor. It also has sealed tapered roller bearings used for
centering the drive shaft and shouldering thrust and radial loads
on the device.
[0016] One advantage of the present invention is that it can
utilize any of a variety of commonly available air hammers. It is
also an advantage of the present invention to not rotate the entire
drill string along with the hammer. The present invention has
bypass tubes for delivering excess compressed air not used by the
vane motor to the hammer drill for its operation. The present
invention also has check valves that send exhausted air from the
vane motor to the well-bore.
[0017] FIG. 1 shows the drill string 100 which comprises a motor
assembly 300, a bent sub assembly 400, and a bottom assembly 500
attached to a hammer 600. The drill string 100 is controlled from
above ground using a drill pipe 50.
[0018] The function of the hammer drill 600 is to pulverize rock
with repeated linear blows. The drill string 100 simultaneously
imparts rotation to the hammer 600 so that the buttons 604 on the
hammer 600 do not repeatedly strike the rock surface in the same
place. The hammer buttons 604 act as mini chisels. The cutting of
the rock or other underground material takes place under the
buttons 604. If the buttons 604 do not move (rotate), zero or
minimal cutting takes place.
[0019] The drill string 100 rotates the entire hammer drill 600 in
rotations per minute similar to rotations supplied by the drilling
rig and drill string. This allows the buttons 604 to rotate across
the entire face of the borehole and thus cut the entire face.
Additionally, the drill string 100 supplies sufficient torque to
overcome the drag on the hammer 600 from the sides of the borehole
that hamper rotation.
[0020] Since the motor 300 supplies the rotation of the hammer 600,
the exterior of the drill string 100 itself need not rotate. This
allows for the bend in the middle of the bent sub assembly 400 so
as to impart a direction to the drilling action. As shown in FIG.
1, the bit of the hammer 600, the outside edge of the bent sub 400,
and the end of the motor assembly 300 form three points in space
that are not in a straight line but instead form an arc. This arc
is the amount of curvature created during the drilling process as
the well bore goes from vertical at the beginning of the drilling
process, to greater and greater angles from vertical as the
drilling progresses around the arc until a horizontal angle is
achieved.
[0021] For the present invention to achieve maximum effectiveness
and convenience, the rotary power source must use the same power
source as the linear power source for the air hammer 600. Having
two separate power sources is not cost-effective, and is also more
difficult to implement. In an exemplary embodiment, the motor
assembly 300 uses compressed air, although the present invention
should not be considered as limited exclusively thereto.
[0022] As shown in FIG. 6, the well-bores contemplated within the
present invention are usually drilled within very narrow space
constraints. The present invention is customized to get it in the
shape and space which is as small a space possible. The present
invention is suited for well-bores as small as 61/4 inches in
diameter. Thus, the drill string 100 of the present invention is
ideally less than six inches in diameter, although other
implementations are possible. The smaller size is needed to have
room in the bore hole for the drill string 100 that incorporates a
bent sub assembly 400 to get down to the intended drill space and
to provide room for cuttings and air to return past the drill
string 100 and up the borehole. Thus, in an exemplary embodiment,
the drill string 100 of the present invention measures 51/2 inches
outside diameter.
[0023] As shown in FIG. 2, the total outside diameter of the drill
string 100 must allow for several threaded connectors on 324, 424,
504, and 524 to fasten all pieces 300, 400, 500, and 600 together.
Additionally, the motor 304 must be small enough to fit inside the
aperture within the drill string 100. As shown in FIG. 2, the
bottom assembly 500, the bent sub assembly 400, and the motor
assembly 300 are joined together with coarse threads. The threaded
connectors on 324, 424, 504 and 524 are assembled with torques
sufficient to keep the drill string 100 from disassembling during
use, and are also designed to withstand very high tensional forces
occasionally encountered during the drilling process, as well as
provide a tight seal for routing the air necessary to drive the
hammer 600.
[0024] As shown in FIG. 3A, the present invention uses part of the
compressed air stream that is supplied by the above-ground drilling
rig or auxiliary compressor to operate the hammer drill. Typically,
hammer drills in the air drilling process require between 600 and
900 cubic feet of air per minute to operate and remove drill
cuttings from the borehole. If more air is needed, then an
auxiliary compressor can be added.
[0025] As shown in FIG. 3B, a regulator 338 will limit the air
pressure of the compressed air before it gets to the vane motor
304. Air pressure is regulated so as to not overdrive the vane
motor 304 yet provide the optimum pressure for the vane motor to
function effectively. The vane motor 304 has devices that turn like
the blades of a fan or turbine. The regulator and motor are located
in a low pressure air chamber contained by a motor housing plate
390.
[0026] As shown in FIG. 3B, the motor assembly 300 has check valves
342 which are the ports where the air is exhausted out from the
vane motor 304 to the well bore. The check valves 342 keep fluids
and cuttings from entering the interior of the device when air is
not being exhausted. This exhaust air is the same approximate 100
cubic feet per minute air that is used to run the vane motor 304
that supplies the power to the sun pinion 312 and planet gears 316,
and in turn drive the keyed shaft 334. The exhausted air also aids
in cuttings removal. The check valves 342 are one-way so as to
prevent drilled materials from flowing back into the drill string
100.
[0027] The regulator 386 ensures that a specific, fixed amount of
air at a constant pressure arrives at the motor 304. Meanwhile, the
air filter 380 preserves the motor 304. The filter 380 removes all
coarse material typically found in compressed air streams found on
drilling rigs.
[0028] The motor 304 must be small enough to fit inside the tube of
the motor assembly 300, and also allow space for tubing 311 to be
placed alongside the motor 304. As shown in FIGS. 3A and 3B, this
tubing 311 allows a supply of air from the above ground air
compressor to be not directed at the motor 304 and instead be
supplied to the hammer 600.
[0029] As shown in FIG. 3B, the motor assembly 300 also contains
threaded plugs for lubrication. The plugs will allow the insides of
the gearbox in the motor assembly 300 to be filled with lubricating
oil or grease after the device is assembled. The threaded screws
308 attach the gearbox housing and motor mount plates to the
exterior tube of the motor assembly 300.
[0030] The top gear hub and the gear hub base (FIG. 3A) exist to
hold the planet gears 316 in place with the proper alignment, so
that they have the optimum contact with the sun pinion 312. FIG. 3A
shows a helical gear configuration in the gearbox. However, other
embodiments such as a configuration with spur gears may also be
utilized.
[0031] The gearbox housing 314 is comprised of the internal gear
and two end plates. The gearbox housing remains fixed because it is
attached to the wall of the outside shell of the housing 324 by
housing screws 308. The planet gear assembly rotates inside the
cavity of the gearbox housing. As shown in FIG. 3A, the motor 304
has a square shaft that is attached to the stem pinion sun gear 312
that has a square socket.
[0032] As shown in FIG. 4, within the bent sub assembly 400 there
are 2 U-joints. These act as two different independent links, with
another shaft 428 in between the two. The two universal joints thus
work in tandem, so that the rotation of the drive shaft through the
bent sub 400 has a smooth action. A square shaft 420 is attached to
the bottom universal joint.
[0033] As shown in FIG. 5, the square shaft fits in a slip sleeve
that transfers torque from the universal joints to the drive shaft
510. One half inch keyways and keys are used to impart torque from
the gearbox keyed shaft to the top universal joint, between the
universal joints, and between the bottom universal joint and the
square shaft 420. Two 1/2 inch keyways and keys impart the torque
from the keyed shaft 334 to the universal joints and shaft 428 in
the bent sub 400.
[0034] As shown in FIG. 4, the bent sub assembly 400 can be built
with a specific angle bend, measured in degrees. As shown in FIG.
4, the bent or sloped area 484 can be built with a variety of
slopes or bends, hence the name "bent sub assembly". Some exemplary
measurements can be 0.75 degrees, 1 degree, 2 degrees, and
potentially higher amounts. An operator of the present invention
can adjust the amount of angle created during the drilling process
by changing out the bent sub assembly 400 with an assembly that has
a different bend.
[0035] As shown in FIG. 5, the shear pins 504 attach the bearing
supported drive shaft 520 to the box 505 where the hammer 600 is
attached. The pins 504 secure the box to bearing supported drive
shaft 420 under normal and occasionally high tension loads
sometimes experienced in certain in down-hole conditions. Keyways
and keys are placed perpendicular to the pins 504 to impart torque
from the drive shaft 520 to the box 505. The optional stabilizer
534 keeps the tool centered in the hole and keeps most of the side
load off of the hammer 600.
[0036] The drive shaft 510 is centered within the bearing housing
524 by means of tapered roller bearings 512. Accordingly, FIG. 5
shows how the bottom assembly 500 keeps the drive shaft centered
with the roller bearings 512. The drive shaft is attached to the
box coupling 505 by means of shear pins 504. The box coupling 505
is the bottom connection of the device that contains tapered
threads 524 which connect to the threaded pin of the air hammer
600. The box coupling 505 transfers thrust loads from the hammer
600 to the bottom taper roller bearing 512. These tapered roller
bearings 512 can take both axial and radial loads. By locating them
opposite each other, as shown in FIG. 5, the bearings ensure that
the hollow drive shaft remains centered and does not wobble.
[0037] The bottom assembly 500 further serves to transfer air flow
channeled through the bent sub assembly 400 to the hammer 600. The
hammer 600 obtains all of its non-rotational longitudinal hammering
force from high pressure air flow. This air flow is sent through
the interior aperture of the drive shaft 510 to the hammer.
[0038] The drive shaft 510 and box coupling 5050 is secured within
the bottom assembly 500 by means of retaining rings. Accordingly, a
retainer piece assembly 800 fits as shown in FIG. 8 ensures that
the drive shaft does not slide through the top taper roller
bearing.
[0039] FIG. 6 shows one possible implementation of the present
invention. A drill string 100 is located within a wellbore. The
exteriors of the motor assembly 300, bent sub assembly 400, and
bottom assembly 500 do not rotate. However, the box coupling 505
and hammer 600 rotates. The entire drill string 100 is operated by
making changes to the drill pipe 50 at the drill rig at the ground
level.
[0040] It is important to understand how various portions of the
drill string 100 rotate, while others do not. The planet gears 316
and sun pinion 312 as well as keyed shaft 334 rotate, while the
threaded housings 324, 424, and 524 remain fixed. Additionally, the
drive shaft 510, tapered roller bearings 512, coupling 505, shear
pins 504, and drive shaft 520 all rotate.
[0041] A cross section of the motor assembly 300 is shown in FIG.
7, cut along the lines A-A in FIG. 3A. In FIG. 7, the single-piece
stem pinion sun gear 312 made from hardened steel or other
material, is bordered by planet gears 316. However, as stated,
other types of gearing mechanisms could also be used, such as an
arrangement of spur gears. Consequently, the present invention
should not be considered as limited to specific type of gearing
mechanism, and that numerous alternative gearing mechanisms can be
contemplated within the spirit and scope of the present
invention.
[0042] A perspective view of the retainer assembly is shown in FIG.
8, which is formed by cutting the bottom assembly 500 along the
lines B-B as shown in FIG. 5. The retainer piece 800 consists of a
two-piece retainer ring 516 and sleeve 520. The drive shaft 510 is
notched on the exterior to fit the inside diameter of the two piece
retainer ring 516. The two piece retainer ring 516 is secured
against the hollow drive shaft by the retainer sleeve 520, and
squeezes up against the drive shaft so as to prevent lateral
movement.
[0043] The present invention is configured to allow for the
compressed air not utilized by the vane motor 304 to bypass that
motor and instead flow through the device to the air hammer 600. To
achieve this bypass, the drill string 100 of the present invention
has bypass tubes 311 that direct compressed air from the chamber
that houses the filter past the chamber that houses the regulator
324 and vane motor 304 to a chamber housing the sun gear 312 and
pinion gear 316.
[0044] As shown in FIGS. 3A, the gear box housing 314 has flutes
cut laterally along its length to allow for the bypass air to reach
the bent sub assembly 400. The air then flows past the universal
joints in the bent sub assembly 400 to the bottom assembly 500. The
air is then exhausted through the hollow drive shaft 510 and box
coupling 505 to the air hammer 600.
[0045] It is an advantage of the present invention that it allows
for a drilling process that requires minimal torque. Thus the
connections within the drill string 100 can be made up with tools
typically found on drilling rigs. No high torque tools are
needed.
[0046] It is anticipated that various changes may be made in the
arrangement and operation of the system of the present invention
without departing from the spirit and scope of the invention, as
defined by the following claims.
* * * * *