U.S. patent number RE37,450 [Application Number 09/488,914] was granted by the patent office on 2001-11-20 for directional multi-blade boring head.
This patent grant is currently assigned to The Charles Machine Works, Inc.. Invention is credited to Arthur D. Deken, Cody L. Sewell.
United States Patent |
RE37,450 |
Deken , et al. |
November 20, 2001 |
Directional multi-blade boring head
Abstract
Directional boring bits (1100, 1200) are disclosed which have at
least one roller cone (1202, 1104) and also each define a
deflecting surface (1104) for deflecting the boring bit when the
bit is advanced without rotation. The borehole can be curved by
pushing the bit forward without rotation.
Inventors: |
Deken; Arthur D. (Perry,
OK), Sewell; Cody L. (Perry, OK) |
Assignee: |
The Charles Machine Works, Inc.
(Perry, OK)
|
Family
ID: |
27535753 |
Appl.
No.: |
09/488,914 |
Filed: |
January 19, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
067298 |
May 25, 1993 |
5341887 |
|
|
|
857167 |
Mar 25, 1992 |
5242026 |
|
|
|
575568 |
Aug 31, 1990 |
5148880 |
|
|
|
211889 |
Jun 27, 1988 |
4953638 |
|
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Reissue of: |
163756 |
Dec 9, 1993 |
05392868 |
Feb 28, 1995 |
|
|
Current U.S.
Class: |
175/62;
175/376 |
Current CPC
Class: |
E21B
10/08 (20130101); E21B 19/084 (20130101); E21B
10/20 (20130101); E21B 7/06 (20130101); E21B
10/602 (20130101); E21B 10/62 (20130101); E21B
47/017 (20200501); E21B 10/60 (20130101); E21B
21/002 (20130101); E21B 47/024 (20130101); E21B
7/046 (20130101); E21B 7/065 (20130101); E21B
7/26 (20130101); E21B 10/54 (20130101); E21B
47/022 (20130101); E21B 10/42 (20130101); E21B
7/064 (20130101) |
Current International
Class: |
E21B
7/26 (20060101); E21B 47/02 (20060101); E21B
47/01 (20060101); E21B 10/54 (20060101); E21B
47/022 (20060101); E21B 47/024 (20060101); E21B
47/00 (20060101); E21B 7/00 (20060101); E21B
7/04 (20060101); E21B 7/06 (20060101); E21B
19/00 (20060101); E21B 19/084 (20060101); E21B
21/00 (20060101); E21B 10/60 (20060101); E21B
10/00 (20060101); E21B 10/62 (20060101); E21B
10/46 (20060101); E21B 10/08 (20060101); E21B
10/42 (20060101); E21B 10/20 (20060101); E21B
007/00 () |
Field of
Search: |
;175/61,62,19,73,385,398,400,376 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Texas Mill Supply, Inc. advertisement for Curv-O-Mark (undated).
.
Blue Demon For Waterwell, Quarry, and Seismic Applications,
published by the Blue Demon Company, Inc., prior to Feb. 27, 1995
(pp. 1-8)..
|
Primary Examiner: Will; Thomas B.
Assistant Examiner: Petravick; M.
Attorney, Agent or Firm: McKinney & Stringer, P.C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of application Ser. No.
08/067,298, .[.filed on May 25, 1993.]. .Iadd.entitled DIRECTIONAL
MULTI-BLADE BORING HEAD, filed on May 25, 1993, now U.S. Pat. No.
5,341,887, which was a continuation-in-part of application Ser. No.
857,167, entitled, METHOD OF AND APPARATUS FOR DRILLING A
HORIZONTAL CONTROLLED BOREHOLE IN THE EARTH, filed Mar. 25, 1992,
now U.S. Pat. No. 5,242,026, which was a continuation-in-part of
application Ser. No. 575,568, entitled APPARATUS FOR DRILLING A
HORIZONTAL CONTROLLED BOREHOLE IN THE EARTH, filed Aug. 31, 1990,
now U.S. Pat. No. 5,148,880, which was a continuation-in-part of
application Ser. No. 211,889, entitled METHOD OF AND APPARATUS FOR
DRILLING A HORIZONTAL CONTROLLED BOREHOLE IN THE EARTH, filed Jun.
27, 1988, now U.S. Pat. No. 4,953,638..Iaddend.
Claims
We claim:
1. A directional boring head for a boring machine, the boring
machine capable of axially advancing and rotating a drill string
about an axis of rotation underground, the drill string ending in
the directional boring head, said directional boring head
comprising:
a body having a central axis of rotation;
a deflection structure mounted on the body defining a deflecting
surface at an oblique angle to the central axis of rotation of the
body;
.[.at least one.]. .Iadd.a single .Iaddend.roller cone mounted to
said body; and
the deflecting surface deflecting the boring head as the boring
machine advances the drill string without rotation and the
directional boring head drilling a relatively straight borehole as
the boring machine advances the drill string with rotation. .[.
2. The direction boring head of claim 1 having two roller cones
mounted on the body..].
3. The directional boring head of claim 1 wherein a fluid jet is
mounted on the body, the body having a passage for flow of fluid
for discharge from the jet to assist in the drilling.
4. The directional boring head of claim 3 wherein the jet is
oriented to discharge a fluid at the roller cone.
5. The directional boring head of claim 1 wherein the deflection
structure and roller cone are mounted on a bit assembly removably
attached to the body.
6. The directional boring head of claim 1 wherein the rotational
axis of the roller cone intersects the central axis of rotation of
the body..[.
7. The directional boring head of claim 1 having one roller cone
mounted on the body..].
Description
TECHNICAL FIELD OF THE INVENTION
This invention relates to a steerable fluid assisted mechanical
boring head for drilling substantially horizontal boreholes under a
roadway or other obstruction.
BACKGROUND OF THE INVENTION
Using boring machines with a steerable bit or head for drilling
horizontal boreholes under a roadway or other obstruction is a well
known practice. The process of providing such boreholes is
generally referred to as "trenchless" digging, since an open trench
is not required. A key to the operation of such a boring device is
to have an effective steerable boring bit or head. If the bit is
steerable, the operator can redirect the borehole along the proper
path if it begins diverting from the desired path, and also allows
the operator to steer around obstructions underground.
Many drill bits have been designed which have such a steering
feature. However, there is a continuing need to develop boring bits
which have better directional control, operate in a variety of soil
conditions effectively and provide enhanced cutting action.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, a
directional boring bit is illustrated which is capable of axially
advancing while the drill string on which the boring bit is mounted
is rotated and is capable of moving in a different direction as the
drill string rotation is stopped and the drill string and boring
bit are thrust forward. The directional boring bit has a body and a
deflecting surface on the body at an oblique angle to the central
axis rotation of the body. The directional boring bit also has at
least one conically shaped rotary cutter or cone mounted thereon to
assist in boring.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of a boring machine as employed in
practicing the method of the invention for drilling a borehole in
the earth.
FIG. 2 is an elevational enlarged scale view of the boring machine
of FIG. 1.
FIG. 3 is a top plan view of the boring machine of FIGS. 1 and 2
taken along line of 3--3 of FIG. 2.
FIG. 4 is an elevational, enlarged scale view of the boring machine
of FIGS. 1 and 2 taken along line 4--4 of FIG. 2.
FIG. 5 is an elevational, cross-sectional, enlarged scale view
taken along line 5--5 of FIG. 2 showing how the drill string is
supported and rotationally oriented.
FIG. 6 is an enlarged elevational view of the boring bit or
downhole tool or downhole tool 173 of FIG. 1 taken at (6) of FIG.
2.
FIG. 7 is a top plan view of the bit of FIG. 6.
FIG. 8 is an end view of the bit of FIG. 6 taken along line 8--8 of
FIG. 6.
FIG. 9 is a broken away perspective view of elements associated
with a second alternative embodiment of a boring machine including
a second alternative embodiment of a downhole tool body.
FIG. 10 is a broken away perspective view of elements associated
with the second alternative downhole tool body of FIG. 9.
FIG. 11 is a side sectional view of the downhole tool body of FIG.
10.
FIG. 12 is a cut-away view of the bottom flat surface of the
downhole tool body of FIGS. 10 and 11.
FIG. 13 is a front view of the downhole tool body of FIGS. 10 and
11.
FIG. 14 is a top view of the downhole tool body of FIGS. 10 and
11.
FIG. 15A is a broken away perspective view of elements associated
with a frame of the second alternative embodiment of a boring
machine.
FIG. 15B is a broken away partial perspective view of a connector
link between a chain and forward end of the frame of FIG. 15A.
FIG. 15C is a broken away partial perspective view of a connector
link between a chain and a thread of the frame of FIG. 15A.
FIG. 16 is a broken away perspective view of a saver sub and an
adapter assembly for a drill string.
FIG. 17 is a bottom view of a dirt blade assembly of FIG. 10.
FIG. 18 is a side view of the dirt blade assembly of FIG. 17.
FIG. 19 is a bottom view of the sand blade assembly of FIG. 10.
FIG. 20 is a side view of the sand blade assembly of FIG. 19.
FIG. 21 is a bottom view of an alternative sand blade assembly.
FIG. 22 is a side view of the sand blade assembly of FIG. 21.
FIG. 23 is an enlarged elevational view of a third alternative
embodiment of a downhole tool and of a portion of a drill
string.
FIG. 24 is a top view of the downhole tool of FIG. 23.
FIG. 25 is a front view of the tool of FIG. 23 taken along line
25--25 of FIG. 23.
FIG. 26 is an exploded view of the blade of the downhole tool of
FIG. 23 illustrating the wear resistant material on the blade.
FIG. 27 is an exploded view of FIG. 24 showing a ball in a check
valve assembly which is disposed inside the fluid passageway and
adjacent the nozzle.
FIG. 27A is a perspective view of the check valve assembly of FIGS.
24 and 27.
FIG. 28 is a partial view of the downhole tool body of FIG. 23
including an alternative embodiment of a blade.
FIG. 29 is a top view of a hard soil/soft rock tapered blade
assembly.
FIG. 30 is a side view of the hard soil/soft rock tapered blade
assembly of FIG. 29.
FIG. 31 is an opposite side view of the hard soil/soft rock tapered
blade assembly of FIG. 29.
FIG. 32 is a bottom view of a spade-like blade assembly.
FIG. 33 is a side view of the spade-like blade assembly of FIG.
32.
FIG. 34 is a bottom view of a relatively wide blade assembly.
FIG. 35 is a side view of the relatively wide blade assembly of
FIG. 34;
FIGS. 36-59 illustrate various drill bits that can be used;
FIG. 60 is a perspective view of a directional multi-blade boring
head;
FIG. 61 is a front view of the boring head;
FIG. 62 is a side view of the boring head;
FIG. 63 is a perspective view of a modified directional multi-blade
boring head;
FIG. 64 is a front view of the boring head;
FIG. 65 is a side view of the boring head;
FIG. 66 is a perspective view of a directional boring head;
FIG. 67 is an end view of the boring head of FIG. 66;
FIG. 68 is a side view of the boring head of FIG. 66;
FIG. 69 is a perspective view of a directional boring head forming
a second embodiment of the present invention;
FIG. 70 is an end view of the boring head of FIG. 69; and
FIG. 71 is a side view of the boring head of FIG. 69.
DETAILED DESCRIPTION
Referring to the drawings, and first to FIG. 1, the environment in
which the apparatus of this invention is used is illustrated. The
boring machine is generally indicated by the numeral 10. Machine 10
is shown resting on earth's surface 12 and in position for forming
borehole 14 underneath an obstruction on the earth such as roadway
16. As shown in FIG. 1, by using extended range boring machine 10,
the direction of the borehole can be changed as the borehole passes
under roadway 16. This illustrates how machine 10 can be utilized
to form borehole 14 under an obstruction without first digging a
deep ditch in which to place a horizontal boring machine, and, also
without having to dig a deep ditch on the opposite side of the
obstruction where the borehole is to be received. While the method
of drilling a borehole and the machine used therewith will be
described as showing the borehole being drilled from the earth's
surface 12, it can be appreciated that machine 10 can be used in a
shallow ditch if desired. It should be kept in mind, however, that
the main emphasis of the method and machine of this invention is
that of drilling a borehole in which the direction of the borehole
can be changed during the drilling process. These methods could be
applied on other types of drilling machines as well.
In conventional fashion, drill string 44 is simultaneously rotated
and advanced by means of boring machine 10 to establish a borehole
in the earth. The drilling operation, wherein pipe 42 of FIG. 2 is
simultaneously rotated and axially advanced, is continued until a
change in direction of the borehole is desired. This typically
occurs when the borehole is near a desired depth and when the
borehole is to be moved substantially horizontal for a distance. In
order to change the direction of the borehole the-following
sequence is employed:
1. The rotation of drill string 44 is stopped.
2. The rotational position of drill string 44 is oriented so that
blade assembly 72, 172, 172', 272, 372, 472, 572, 672 or 772 of
downhole tool 58, 158 or 358 is inclined at an acute angle relative
to the longitudinal axis of the drill string and towards the new
direction of the borehole desired.
3. The drill string is axially advanced without rotation to axially
advance downhole tool 58, 158 or 358 a short distance such that the
blade assembly moves the downhole tool in the earth towards the new
desired direction.
4. Simultaneous rotation and axial advancement of the drill string
is resumed for a short distance.
5. Sequentially repeat steps 1, 2, 3 and 4, until the direction of
the borehole is in the new direction desired.
Thereafter, the downhole tool 58, 158 or 358 is axially advanced
and simultaneously rotated until it is again desirable to change
directions. This typically can occur when a borehole has reached a
point adjacent the opposite side of the obstruction under which the
borehole is being drilled. At this stage in the drilling of the
borehole, it is desirable to have the direction of the borehole
inclined upwardly so that the borehole will emerge at the surface
of the earth on the opposite side of the obstruction.
To again change the direction of the borehole, the same sequence is
repeated. That is, the rotation of drill string 44 is stopped, the
orientation of the drill string is corrected so that the downhole
tool blade assembly is inclined in the newly desired direction
(that is, in this example, upwardly), the drill string is axially
advanced without rotation a short distance, the drill string is
then rotated and axially advanced a short distance, and the
sequence is repeated until the new direction of drilling the
borehole is attained. After the new direction is attained, the
borehole is drilled by simultaneously rotating and advancing the
drill string until the borehole is completed.
Referring to FIGS. 2 and 3, more details of the boring machine are
illustrated. In particular, machine 10, which is utilized for
practicing a method of this invention, includes frame 18 having a
forward end 18A and a rearward end 18B and supportable on the
earth's surface. Frame 18 of FIGS. 2 and 3 and frame 118 of FIGS.
15A-15C are preferably operated from a surface launch position
which eliminates the need to dig a pit. Also, frames 18 and 118
provide an elongated linear travel pathway. As best seen in FIGS.
4, 5 and 15A the linear pathway is preferably provided by spaced
apart parallel channels 20 and 22 or 120 and 122.
Rotary machine 24 of FIGS. 2, 3 and 4 is supported on the frame and
in the travel path. More specifically, rotary machine 24 is
supported on wheels 26 of FIG. 4 which are received within channels
20 and 22.
Drill string 44 includes a plurality of drill pipes 42 each having
a male thread at one end and a female threaded opening at the other
end. Each pipe is attachable at one end to rotary machine 24 and to
each other in series to form drill string 44. As seen in FIGS. 2
and 3, the rearward end of drill string 44 can be attached to
rotary machine 24. Drill string 44 can also include adapter 230 and
saver subs 232, as in FIGS. 9 and 16. Thread caps 234 and 236 are
used to protect a drill pipe and are removed prior to insertion
into the drill string.
Rotary machine 24 is supplied by energy such as by hydraulic
pressure through hoses 28 and 30 of FIGS. 2 and 4. This hydraulic
energy can be supplied by an engine drive trailer mounted hydraulic
pump (not shown) which is preferably positioned on the earth's
surface adjacent the drilling machine. The use of hydraulic energy
is by example only. Alternatively, rotary machine or drive 24 could
be operated by electrical energy, an engine or the like. The use of
hydraulic energy supplied by a trailer mounted engine driven pump
is preferred, however, because of the durability and dependability
of hydraulically operated systems. Third hose 32 of FIGS. 2 and 4,
is used for supplying fluid for a purpose to be described
subsequently.
By means of control levers 34 of FIG. 2, hydraulic energy can be
controlled to cause rotary machine 24 to be linearly moved in the
pathway provided by channels 20 and 22 of FIGS. 4 and 5 or 120 and
122 of FIG. 15A, and at the same time to cause a drill pipe to be
axially rotated. The linear advancement or withdrawal of rotary
machine 24 is accomplished by means of chain 36 of FIG. 2 or chain
136 of FIG. 15A which is attached at one end to frame front end 18A
or 118A and at the other end to frame rearward end 18B or 118B.
Chain 36 passes over cog wheel 38, the rotation of which is
controlled by one of levers 34 to connect hydraulic power to a
hydraulic motor (not shown) which rotates cog wheel 38 in the
forward or in the rearward direction or which maintains it in a
stationary position.
As seen in FIGS. 2 and 3, extending from the forward end of rotary
machine 24 is drive spindle or shaft 40 which has means to receive
the male or female threaded end of drill pipe 42. Upper or uphole
end 60 of the drill string is attached to shaft 40 (FIG. 2), that
is, to the rotary machine 24. Saver sub 232, attached to shaft 40
with a thread retaining compound such as Loctite.RTM. RC/680 is a
replaceable protector ("saver") of threads on shaft 40.
A plurality of drill pipes 42 are employed and, when the drill
pipes are assembled together, they form drill string 44 as seen in
FIG. 1. Drill pipes 42 are of lengths to fit a particular size
drill frame 18 or 118, such as 5 feet, 10 feet, 12 feet and/or 20
feet, and when sequentially joined can form a drill string of a
length determined by the length of the hole to be bored. The
preferred embodiments generally have a distance capability of over
400 feet in many soil conditions.
As seen in FIGS. 2 and 5, adjacent forward end 18A of the frame is
drill pipe support 46. Drill pipe support 46 maintains drill pipe
42 in a straight line parallel to the guide path formed by channels
20 and 22. The drill pipe support can include sight 48, the purpose
of which will be described subsequently.
Positioned adjacent the forward and rearward ends of frames 18 or
118 are jacks 50 or 150 by which the elevation of the frame
relative to the earth's surface 12 may be adjusted. In addition, at
front end 18A of the frame are opposed stakes 52 and 54 which are
slidably received by the frame front end. Stakes 52 and 54 may be
driven in the earth's surface so as to anchor the machine during
drilling operation.
Also illustrated in FIG. 15A are flange lock bolt 117 and flange
lock nut 119 for attaching rearward end or rear cross-member 118B
of frame 118 to channels 120 and 122. Also, as seen in FIG. 15C,
thread 113 (attached to rearward end 118B by nuts 111) adjustably
engages chain 136 via connector link 137. In addition, as seen in
FIG. 15B, the opposite end of chain 136 also engages forward end
118A of frame 118 via second connector link 137.
Affixed to downhole end 56 of drill string 44 is a bit or downhole
tool generally indicated by the numeral 58. The drill bit or
downhole tool is best seen in FIGS. 6, 7 and 8.
The drill bit or downhole tool includes body portion 62 which has
rearward end portion 64 and forward end portion 66. Rearward end
portion 64 of drill bit body 62 includes an internally threaded
recess 68 which receives the external threads 70 of drill string
forward end 56.
Blades or blade assemblies 72, 172, 172', 272, 272', 372, 472, 572,
672 and 772 can be affixed to drill bit or downhole tool bodies 62,
162 or 362. The plane of blade assemblies 72, 172, 172', 272, 272',
372, 472, 572, 672 and 772 are inclined at an acute angle to axis
X--X of the bit's internally threaded recess 68. Axis X--X is also
the longitudinal axis of drill string 44 or forward most drill pipe
42. That is, axis X--X is the axis of the portion of the drill
string immediately adjacent and rearwardly of the downhole
tool.
The blade assemblies are preferably sharpened at their outer
forward ends 72A, 172A, 272A, 372A, 472A, 572A, 672A and 772A. When
rotated, the blade assemblies cut a circular pattern to form walls
6 or 6' at end 4 of borehole 14 as illustrated in FIGS. 6 and
23.
Bodies 62, 162 and 362 have fluid passageway 78 therethrough
connecting to jet or nozzle 76. Fluid passageway 78 is in turn
connected to the interior of tubular drill string 44. As previously
stated with reference to FIG. 2, hose 32 provides means for
conveying fluid under pressure to boring machine 24. This fluid is
connected to the interior of drill pipe 42 and thereby to the
entire drill string 44, and, thus, to the interior of bodies 62,
162 and 362. The fluid is ejected from tool bodies 62, 162 and 362
through nozzle 76 to aid in the drilling action. That is, fluid is
ejected from nozzle 76 to cool and lubricate blade assemblies 72,
172, 172', 272, 272', 372, 472, 572, 672 or 772 and flush away
cuttings formed by the blade as it bores through the earth by
forming a slurry of cuttings.
Nozzle 76 in this case refers to any of a plurality of fluid
nozzles designed for different soil conditions. For example, one
can use one nozzle for soft dirt or hard dirt and then interchange
that with another nozzle for sand. Also, one can interchange
nozzles to vary the flow rate.
As best seen in FIGS. 6 and 7, blade assembly 72 includes an outer
surface which is substantially flat. Also, blade assembly 72 is
rectangular as illustrated.
The preferred downhole tool improves the ability to make rapid
steering corrections. Downhole tool body 62, 162 and 362 include a
tapered portion, between the rearward end 64 and the forward end
66, which tapers toward the forward end of the drill body. Also,
this surface of the drill body defines an outer surface which is
free of cutters, except for the blade.
Although not necessary, downhole tool body 62 has a substantially
triangular cross-section defined by a converging flat top surface
90 and flat bottom surface 92. Also, blade assembly 72 is fixed to
the bottom flat surface of the drill bit body and extends axially
beyond forward end 66 of body 62 at an acute angle. This angled
extension, in conjunction with converging top surface 90 of the
drill bit body, defines relief space 8 in which fluid nozzle 76 is
positioned. In use, relief space 8 will form a cavity in the
borehole which will facilitate rapid steering corrections. Thus,
the structure in FIG. 6 illustrates this acute angle of the blade
assembly and the tapered portion of the drill body having the
uniquely advantageous function of defining a relief area or space 8
of reduced axial resistance near forward end 4 of borehole 14 to
thereby allow for rapid deviation of the borehole from a
straightline when downhole tool 58 is thrust forward without
rotation.
Although the invention provides an improved rapid steering
correction function in a downhole tool with both a blade assembly
and a fluid jet or nozzle, it is not necessary, though, in certain
circumstances to have a fluid jet to still achieve the desired
advantageous functions. A preferred structure, however, is blade
assembly 72 having an outer surface which is substantially flat and
tool body tapered portion which defines an outer surface of the
tool body from which only the blade assembly 72 and nozzle 76
project from.
When a change of direction of the drill pipe is desired, rotation
is stopped and the drill pipe is advanced axially without rotation.
However, in certain soils or ground conditions, it is very
difficult to move the drill pipe forward without rotation. The
relief area 8 shown in FIGS. 6 and 23 which is created by the
structure of the drill bit allows for reduced axial resistance at
least over the relief area when drill string 44 is advanced without
rotation. This relief area 8 of reduced axial resistance may be all
that is needed to provide for rapid or sudden steering corrections.
In some soil or boring situations, however, it may be necessary to
incrementally repeat the rotation and push cycle to get the proper
steering correction to form walls 6 of borehole 14 along a curved
path as in FIG. 1 or some other desired path. The present
invention, thus, provides for improved rapid steering correction
which is not available with known prior art devices.
An orientation directional indicator may be secured to the drill
string adjacent the drill machine so that the angle of the plane of
the drill bit body can at all times be known. Referring back to
FIGS. 2 and 4, a device which is utilized to indicate the
rotational orientation of drill string 44, and thereby the
rotational orientation of drill bit or downhole tool 58, is shown.
Ring member 80 is slidably and rotatably received on drill pipe 42.
The ring has a threaded opening therein receiving set screw 82
having handle 84. When the set screw 82 is loosened, ring 80 can be
slid on drill pipe 42 and rotated relative to it.
Affixed to ring 80 is bracket 85 having pointer 86. In addition to
pointer 86, bracket 85 carries a liquid bubble level 88.
The function of ring 80 with its pointer and bubble level is to
provide means of maintaining the known orientation of the drill
string 44. When a drilling operation is to start, the first length
of drill pipe 42 is placed in the machine and bit or tool 58 is
secured tightly to it. At this juncture, the tool is above ground
and the operator can easily observe the orientation of blade
assemblies 72, 172, 172', 272, 272', 372, 472, 572, 672 or 772. The
operator can then affix ring 80 so that it is in accurate
orientation with the blade, that is, as an example, ring 80 is
affixed so that pointer 86 points straight up with the blade
aligned so that a plane drawn perpendicular to the plane of the
blade would be vertical. With ring 80 so aligned, set screw 82 is
tightened by handle 84. Thereafter, as drill pipe 42 is rotated and
advanced into the earth, ring 80 remains in the same axial rotation
orientation, rotating with the drill string. As the drill string is
advanced by the advancement of machine 24 towards forward end 18A
of the boring machine frame, ring 80 moves with it. It can be seen
that when the boring machine has advanced so that shaft 40 is
adjacent the frame forward end, drilling must be stopped and a new
length of pipe 42 inserted. With drilling stopped, drill string 44
can be aligned with pointer 86 in alignment with pointer 48 affixed
to drill pipe support 46. Ring or collar 80 may then be removed and
inserted on a new length of drill pipe 42 threadably secured to the
drill string and the procedure continually repeated, each time
tightening set screw 88 so that the alignment of the blade is
always known to the operator.
To form borehole 44 in the earth, the operator attaches the drill
pipe and drill bit as shown in FIG. 2, begins rotation of the drill
pipe and at the same time, by means of control levers 34, causes
rotary machine 24 to linearly advance in the travel path of the
frame towards the forward end 18A or 118A of frame 18 or 118. Drill
bit 58, rotating and advancing, enters the earth and forms a
borehole therein. As long as bit 58 is rotated as it is advanced,
the borehole follows generally the axis of the drill pipe. That is,
the borehole continues to go straight in the direction in which it
is started.
In the most common application of the invention wherein the
borehole is started at the earth's surface to go under an
obstruction such as a highway, the borehole must first extend
downwardly beneath the roadway. When the borehole has reached the
necessary depth, the operator can then change the direction of
drilling so as to drill horizontally. This can be accomplished in
the following way: When it is time to change direction, the
operator stops drilling and orients the drill string so that drill
bit blade assembly 72, 172, 172', 272, 272', 372, 472, 572, 672 or
772 is oriented in the direction desired. In the illustrated case
of FIG. 1, the borehole is first changed in the direction so that
instead of being inclined downwardly, it is horizontal. For this
purpose the operator will stop drilling with drill string 44 having
collar pointer 86 pointing straight up, that is, with bracket 84 in
the vertical position. With rotation stopped and the drill string
properly oriented, the operator causes rotary machine 24 to move
forwardly without rotating the drill pipe. After forcing the bit a
foot or two (or as far as possible, if less), the operator begins
rotation of the drill bit and continues to advance the drill string
for a short distance.
After a short distance of rotary boring, the procedure is repeated.
That is, the drill string is reoriented so that the operator knows
the inclination of blade assembly 72, 172, 172', 272, 272', 372,
472, 572, 672, or 772 and then he advances the tool a short
distance as above described without rotation and repeats the
procedure. The procedure may be repeated sequentially for a number
of times until the direction of drilling has changed to that which
is desired. The opposite steering correction will have to be
applied just prior to the bit reaching the desired path in order to
prevent or minimize any overshooting of that path. After the
borehole has been oriented in the desired direction, such as
horizontal, the drilling can continue by simultaneous rotation and
advancement of drill string 44, adding new links of drill pipe 42
as necessary until it is again time to change the direction of
drilling, such as to cause the borehole to be inclined upwardly
towards the earth's surface after the borehole has reached the
opposite of the extremity of the obstruction under which the
borehole is being placed. This is achieved as previously indicated;
that is, by orienting drill string 44 to thereby orient the blade
assembly, advancing the downhole tool without rotation of drill
string 44, rotating and advancing the drill string for a short
distance, reorienting the drill bit or tool and advancing without
rotation and sequentially repeating the steps until the new
direction of drilling is achieved.
The experienced operator soon learns the number of sequences which
are normally required in order to achieve a desired direction of
drilling.
Thus, it can be seen that a method of drilling provided by the
present disclosure is completely different than that of the typical
horizontal boring machine. The necessity of digging ditches to the
opposite sides of an obstruction in which to place a horizontal
boring machine is avoided.
The structure of FIGS. 9-35, which disclose alternative embodiments
for a boring system, will now be described in greater detail. Shown
in FIGS. 9-22 is a second embodiment of a drill string assembly and
a second embodiment of a downhole tool body. Downhole tool body 162
of FIGS. 10-14 at least differs from body 62 of the embodiment of
FIGS. 1-8 in that the jet is no longer at an acute angle to the
centerline of the longitudinal axis of the drill string 557 and the
blade assembly is now removable. If a difference is not identified
between embodiments, the elements described herein to operate
boring machine 10 can be used in the latter discussed
embodiments.
As seen from the combination of FIGS. 9-14 and 3-28, downhole tool
bodies 162 and 362 have fluid nozzle 6 fixed to the fluid
passageway and positioned behind a forward end 72A, 172A, 272A,
372A, 472A, 572A, 672A and 772A of the blade assembly. Nozzle 76
can project from a nozzle receiving portion either on or adjacent
top 190 and 390 of the outer surface of the bodies 162 and 362.
Nozzle 76 can also be recessed into the nozzle receiving portion of
the tool body.
Top surface 190 of body 162 is preferably 20.degree. to the
longitudinal axis X--X of the drill pipe. It can be appreciated
that other types of nozzles or jet orifices could be employed.
Nozzle 76 on bodies 162 and 362 has a centerline Y--Y substantially
parallel to the longitudinal axis X--X of drill pipe 42.
Preferably, as most clearly seen in FIG. 28, nozzle 76 is displaced
laterally from the longitudinal axis X--X of drill pipe 42 so that
a fluid stream is emittted above the blade. Also, nozzle opening or
orifice 77 size is governed by factors such as pump capacity, fluid
viscosity and flow rate desired downhole.
Blade assemblies 72, 172, 172', 272, 272', 372, 472, 572, 672 and
772 include an outer surface which is substantially flat. Blade
assemblies 172, 172', 272, 272', 372, 472572, 672 and 772 are
removably mounted on the tapered portion of the downhole tool body
so that the blade assembly is at an acute angle to the longitudinal
axis X--X of the drill pipe and the blade assembly is extending
beyond the forward end 166 and 366 of the downhole tool bodies 162
and 362. Having removable blade assemblies means that the blade can
be replaceable without having to replace the body. This results in
substantially, lower operating cost. Also one obtains versatility,
because one can use a variety of cutter blade assemblies for
trenchless installations in various soil types without having to
invest in a plurality of downhole tools.
The means for mounting removable blade assemblies is especially
important, because of the high stress which these blades undergo. A
preferred mode for mounting a removable blade assembly includes
having apertures on blade assembly receiving surfaces 192 and 392
of the outer surface of the tool body and having corresponding
apertures on the blade assemblies. Also, the blade assemblies are
preferably disposed directly adjacent and flush mounted with
shouldered sections 169 and 369 of tool bodies 162 and 362.
Furthermore, shouldered sections 169 and 369 are preferably at an
angle 10.degree. to a line perpendicular to axis X--X.
Apertures on body 162 are identified as elements 180-183 in FIGS.
11-14 and apertures on body 362 are identified as elements 380-83
in FIGS. 23 and 25. Apertures on blade assembly 172 are identified
as elements 175 and 177-79 in FIG. 17. Apertures on blade assembly
272 are identified as elements 275 and 277-279 in FIG. 19. Also,
apertures on blade assembly 572 are identified as elements 575 and
577-9 in FIG. 29, apertures on blade assembly 672 are identified as
elements 675 and 677-79 in FIG. 32, and apertures on blade assembly
772 are identified as elements 775, and 777-79 in FIG. 34. As seen
in FIG. 10, each blade assembly is removably mounted on the
downhole tool body by means of a plurality of bolts 194 mounted
through the corresponding apertures and substantially flush with an
outer surface of the blade. Preferably bolts 194 are coated with a
thread retaining compound, such as Loctite.RTM. 242, and torqued to
40 ft.-lbs. by wrench 199.
Different types of removable blade assemblies are preferred. One
blade type, represented by preferred blade assemblies 172 and 172'
in FIGS. 10, 17 and 18, is for cohesive soils and soils that offer
a reasonable amount of steering resistance. Thus, blade assemblies
172 and 172' are primarily for dirt/clay conditions. Blade assembly
172 is preferably 21/4 inches wide, 7 inches long and 1/2 inch
thick and preferred for dry/hard clay. Alternative blade assembly
172' is slightly wider at 21/2 inches. The wider blade assembly
172' would be preferable for less resistant applications such as
moist or soft dirt/clay conditions. The wider blade assembly is
more advantageous in these softer dirt applications, because the
wider the blade assembly the more steering force one obtains.
Even wider 3" blade assemblies 272 or 272' of FIGS. 19-22 are
preferred for sandy soils and other loose soils of little
resistance. In these sandy soils, a big surface area blade assembly
is desired. The additional width provides improved steering
response.
Wear resistant material is added in selective areas of the blade
assemblies for additional durability. As seen in FIGS. 17 and 18,
blade assembly 172 includes wear resistant material 185 such as a
carbide strip on the underside of forward portion 173 of the blade.
Blade assembly 172 also includes wear resistant material 186 and
187 adjacent the underside rear portion of the blade as seen in
FIGS. 17 and 18.
Alternatively, one can place a weld bead 289 (of harder surface
material than the blade) on the forwardmost portion of the blade
and down the edges of the blade as seen in FIGS. 19 and 20.
Basically, it is preferred that all blade assemblies have either
the weld bead or hard facing strips such as carbide on three edges
as shown. It is not desired, though, that the carbide strips and
weld beads be mixed on a blade assembly. Note, however, if the soil
has any rock content, use of carbide strips on the blades is
preferred.
Seen in the alternative 3" blade assembly 272' of FIGS. 21 and 22
is a more preferred location for hard surfacing on a forward
portion of the blade. As seen in FIGS. 21 and 22, the forward
portion of the blade includes strips 284 and 288 of harder surface
material (i.e., carbide) than the blade which are disposed in
recesses on portions of the surfaces of the blade. In particular,
strip 288 is disposed on a right-hand side portion of the bottom or
outer side of the blade when facing endwall 4 of borehole 14 and
strip 284 is on a left-hand side portion of the top or inner side
of the blade when facing endwall 4 of borehole 14. With clockwise
rotating (when looking in the direction of boring) of the blade
assembly, the preferred location of hard surfacing in FIGS. 21 and
22 is more effective in protecting both front corners of the blade
assembly. Consequently, the strips are provided on the portions of
the surfaces of the blade assembly which have the primary contact
with the earth when the tool body is simultaneously rotated and
axially advanced.
It is also preferred that the recesses and the strips of harder
surface material in the recesses cross a centerline of the blade
assembly as seen in FIG. 21. This double reinforcement at the
centerline of the blade assembly is particularly advantageous where
the blade and carbide strips 684 and 688 define a spade-like
profile in the forward portion of blade assembly 672 as seen in the
blade of FIGS. 32 and 33.
In addition, as seen in FIGS. 21 and 22, blade assembly 272
includes hard surface material 286 and 287 in the rear portion of
the blade assembly. This wear resistant material is preferably
either brazed or welded onto the blade.
Downhole tool body 162 includes a forward end 166 and rearward end
164 having an aperture including threads for engaging a drill pipe.
As seen in FIG. 11, an intermediate portion of tool body 162 has
cavity 165 for receiving a transmitter and first fluid passageway
163A.
As can be appreciated from FIGS. 10 and 11, transmitter 220 is
disposed in cavity 165 of the intermediate portion of the body.
Pulling tool or wrench 218 is preferably used to install
transmitter 220 in cavity 165. Transmitter 220 produces an
electromagnetic signal which allows the position and depth of tool
body 162 to be determined by use of an above-ground receiver.
The rotational orientation of blade assembly 172 et al., must also
be known when advancing without rotation to make course direction
changes. An angle or roll sensor, such as those known in the art,
can be used in conjunction with the above transmitter/receiver
system to determine blade rotational orientation or aid in
positioning the blade assembly at a particular desired orientation.
Although downhole roll sensing is preferred, tophole drill string
indicating means, such as described in the parent U.S. application
Ser. No. 07/211,889, may be employed to determine blade
orientation.
Removable plug 214 of FIG. 10 is disposed on a rearward portion of
cavity 165 of the intermediate portion of the body. Plug 214 is
also installed with pulling tool or wrench 218. The plug is
waterproof and it is positioned in the body for diverting
pressurized fluid from drill string 44 to first passageway 163A of
the intermediate portion of the tool body. In other words, as the
fluid comes down the center of fluid pipe (i.e., drilling cap) 210
in FIGS. 9 and 10, the fluid path is deviated as it hits plug 214.
The fluid path is diverted downward through first passageway 163A
of tool body 162 of FIG. 11. An advantage of this arrangement is
that plug 214 is removable. Thus, one can get into body 162 or 362
to replace battery 222 of transmitter 220. Also, while performing a
fluid deviating function, the plug protects the transmitter from
fluid. Consequently, an additional advantage of this structure is
that it allows the on-board transmitter to be disposed very close
to the drill bit.
The downhole tool further comprises O-rings 212 and 216 adjacent
each end of plug 214. Also, adjacent the forward end of the tool
body is second fluid passageway 163B and third fluid passageway
163C. Second passageway 163B is in fluid communication with and
substantially perpendicular to first passageway 163A. Third
passageway 163C is in fluid communication with and substantially
perpendicular to second passageway 163B. It would be understood by
one of ordinary skill in the art that the passageway adjacent the
connection of first passageway 163A with second passageway 163B
would be tightly sealed at shouldered section 169 and at outer end
170. Also, as can be appreciated from FIGS. 9-11, fluid nozzle 76
is fixed to the fluid passageway and associated with forward end
166 of body 162.
FIGS. 9, 10 and 16 illustrate elements for an arrangement wherein
nozzle 76 or the like is actually moved up the drill string and
inside saver sub 232 or inside adapter 230. In particular, drill
string 44 includes a channel for transferring fluid from the
exterior of the borehole to the front of the drill string. In FIG.
10, is fluid outlet 171 fixed to the fluid passageway and
associated with downhole tool body 162.
When boring in sandy situations, it is preferred to place the
nozzle rearward of the tool body and install it in saver sub 232 or
adapter 230. As can be appreciated from FIG. 9, disposed adjacent
drive spindle 40 and the back end of drill string 44 is saver sub
assembly 232. As shown in FIG. 16, within saver sub assembly 232 is
filter seating plug 245 which is internally threaded to hold nozzle
76. If inserted in saver sub 232, inner nozzle 76 meters the amount
of and controls the rate of fluid that the surface fluid pump
discharges into borehole 16. Once ejected from that inner nozzle,
the fluid fills drill string 44 and exits out through outlet or
building 171 in tool body 62, 162 or 362. The hole in outlet or
bushing 171 is large enough so that the downhole debris entering
drill string 44 when the flow stops will likely be flushed back out
when the flow resumes. In the preferred embodiments, outlet 171 has
a diameter approximately the same as the diameter of the fluid
passageway. This arrangement is particularly beneficial when
drilling in sand or sandy soils where sand particles flowing back
into a small orifice nozzle located at end 166 of body 162, could
at least partially plug the opening when pressurized flow is
resumed.
When installing the nozzle in saver sub 232, the operator must be
careful. When the fluid pump is turned on, the pressure gauge will
begin to show pressure before fluid ever reaches the tool body.
Even though the gauge shows pressure, the operator must wait until
the fluid has reached the tool body. This waiting time varies
depending upon whether there are just a few feet or a few hundred
feet of drill pipe in the ground. If the operator happens to thrust
the tool body forward before fluid reaches it, there is the
possibility of plugging the tool body. If drilling is continued
while the tool body is plugged, damage to the transmitter can
occur.
To reduce the operator involvement in this process, one can
alternatively install nozzle 76 in adaptor 230. By installing
nozzle 76 in adapter 230, the operator knows that when the gauge
pressures up, the fluid is at the tool body. This is true whether
there are thirty feet or three hundred feet of pipe in the
ground.
Saver sub 232 and adapter 230 both include filter and gasket
combinations 240 and 242 as seen in FIG. 16. Filter and gasket
combination 240 includes 30 mesh coarse screen filter for use with
drilling fluids (bentonite, polymers, etc.). Fluid filter and
gasket combination 242 includes 100 mesh fine screen for use with
water or a water and antifreeze combination. If one uses 100 mesh
filter with drilling fluid, the filter may collapse and stop the
flow of fluid. The purpose of the filters is to remove any
particles from the fluid flow which could obstruct nozzle 76.
FIGS. 23-27A illustrate an alternative tool body embodiment 362. As
shown in FIGS. 23-26, some embodiments function to deflect fluid
from nozzle 76 to an acute angle relative to the longitudinal axis
X--X of the drill pipe. In particular, by having spray from nozzle
76 impinge upon removable cutting blade 372, the deflected jet
stream should more easily allow redirecting of the body out of an
existing borehole. This becomes important if an obstruction is
encountered.
The deflecting portion of blade assembly 372 comprises
wear-resistant material 388 disposed in the blade as seen in FIGS.
24 and 26. Furthermore, the deflecting material 388 includes
concave portion 389 for controlling the fluid spray pattern.
As soils become more difficult to drill, it is preferred to have
the forward end of the blade assembly adjacent the longitudinal
axis X--X of the drill pipe as in FIG. 28. This relationship of the
blade assembly forward end to axis X--X is preferred, because if
one happens to drill into a hard soil or soft rock, the downhole
tool and its drill sting will start rotating around the tip of the
tool. If the blade assembly tip is not on or adjacent the
centerline of the bore, this may cause the rear portion to wobble
and rub against walls of the diameter of borehole 14 which are
behind the bit. Thus, in these situations blade assembly 472 of
FIG. 28 may be more advantageous. Therefore, in the embodiment of
FIG. 28, a forward end 472A of blade assembly 472 is adjacent and
in fact on the longitudinal axis X--X of the drill pipe. For
example, when harder soils or soft rock formations are anticipated,
a tapered (pointed) rather than straight leading edge on the blade
assembly (as in the spade-like blade assembly of FIGS. 32 and 33 or
the stepped-taper blade assembly of FIGS. 29-31) can further aid in
causing the blade assembly to "pilot" into the end of the borehole
and will also rotate more smoothly than a straight-edged bit in
such hard conditions.
In soft soils, however, it is preferred to have the forward end of
the blade assembly extend beyond the longitudinal aids X--X of the
drill pip as in FIGS. 23-26. In soft soils, the tool will not tend
to pilot on the face of the bore but instead will slip across it.
In fact, for such soils it is advantageous for the blade assembly
to be above (i.e., beyond) the centerline of the borehole in order
to provide more steering force. It should be recognized that the
above principle would apply whether or not deflecting of the spray
is employed. By varying the lateral displacement of the jet
relative to the X--X axis, a deflecting of the spray can be
accomplished for the various types of blades discussed herein.
Shown in FIGS. 24, 27 and 27A is ball check valve 394 to prevent
sand or the like from plugging the nozzle opening. When boring a
hole in a tight formation, there tends to be a head pressure in
borehole 16 at front portion 166 or 366 of downhole tool 162 or
362. Therefore, when one shuts off fluid flow to drill string 44 in
order to, for example, add another piece of drill pipe, external
debris-laden fluid in the borehole can actually flow upstream and
into the drill pipe. Cuttings such as grains of sand and the like
which enter nozzle 76 may plug the relatively small nozzle orifice
77 and, after adding a new piece of drill pipe and beginning fluid
pressure through the fluid passageway, restrict or prevent the
start of flow again.
It is preferred, therefore, to have check valve 394, disposed in
the passageway, for opening the passageway when fluid pressure in
the passageway towards nozzle 76 and on valve 394 is greater than
pressure from borehole 16 on valve 384, and for closing the
passageway when pressure from borehole 16 on valve 394 is greater
than fluid pressure in the passageway towards nozzle 76 and on
valve 394. The preferred valve includes ball 395 for preventing
external downhole particles from entering a portion of the fluid
passageway which is upstream of the ball. Also, included in valve
394 is roll pin 397.
Even with an essentially horizontal drill string, there is a
tendency for fluid to flow out of nozzle 76 during the addition to
the drill string or other work stoppages. This tends to be wasteful
of drilling fluid and also causes delays in re-initiating the
drilling operation, because of the time required to refill the
drill string and reach operating pressure. This factor can become
significant when drilling longer boreholes. Thus, the check valve
means also preferably includes spring 396 disposed in the
passageway and on a front side of the ball. The spring provides
little pressure. In fact, the spring only biases the check valve
closed with sufficient force to hold fluid in the drill string when
pump flow is stopped and another joint of pipe is added to the
drill string. In particular, the light spring force only causes the
ball to close the passageway when the pressure of fluid in the
passageway towards nozzle 76 and on ball 395 is less than 10-20
PSI.
As discussed herein, as an alternative to using ball check valve
394 one can use nozzle 76 in saver sub assembly 232 in combination
with outlet 171. If the nozzle 76 is moved to adapter 230 instead
of saver sub 232 for operation in sand, however, the ball check
valve may preferably be used in combination with the nozzle to
prevent plugging since nozzle 76 is only about a foot behind
forward portion 166 (containing bushing/outlet 171) of body 162. In
fact, a further reason for having the nozzle in adapter 230 at the
downhole end of the drill string is to make use of the
spring-biased check valve method of keeping the drill string
full.
When drilling with nozzle 76 in saver sub 232 or adapter 230 and
with check valve 394 installed in place of the nozzle on the tool
body, one will reduce the change of mud and fluid being sucked back
into the housing while breaking loose drill pipe to add another
joint. This should also reduce the chance of plugging the tool
body. In addition, it should reduce the possibilities of damaging
the transmitter 220. Note, however, it is strongly suggested that
one should not run nozzles in both the tool body and adapter 230 at
the same time.
Also, one can also utilize two or more jets instead of one. It is
preferred that these jets also be displaced vertically from the
centerline of the housing as in FIGS. 13 and 23 and side by side.
In other words, the front of body 362 of FIG. 25 can be modified to
include one or more nozzles 76 laterally displaced from
longitudinal axis X--X of drill pipe 42.
Shown in FIGS. 29-31 is removable blade assembly 572 for hard soil
or soft rock cutting. In particular, blade assembly 572 is for
drilling harder formations such as soft sedimentary rocks (i.e.,
sandstone or even soft limestone). Stepped-taper blade assembly 572
is advantageous because it has improved steering control. Blade
assembly 572 includes a forward portion including end 572A, which
when mounted on the tool body, projects beyond a forward end of the
drill body. The forward portion of blade assembly 572 preferably,
when viewed from its top as in FIG. 29, has a staggered profile
which steps rearwardly from a forwardmost point 572A at a center of
the blade to an outside of the forward portion of the blade.
As discussed with respect to blade assembly 272 of FIGS. 21 and 22
and blade assembly 672 of FIGS. 32 and 33, blade 572 also
preferably includes a plurality of strips 584A-E which are disposed
on recessed portions of the top and bottom surfaces of the
substantially flat blade assembly. These strips have the primary
contact with the earth when the blade assembly is simultaneously
rotated and axially advanced.
The forward portion of a top of blade assembly 572 is a mirror
image of a forward position of a bottom of blade assembly 572.
Furthermore, as discussed it is preferred to have strips 584A on
the top and bottom surfaces extend across the centerline of blade
assembly 572 and to have these same strips extend forward of the
forwardmost point of the blade as illustrated in FIGS. 30 and
31.
Forward portion of blade assembly 572 is wider than rear portions
of the blade for smoother operation when rotated in hard soil or
soft rock formations. Also, bottom edges 586 and 587 include wear
resistant material such as carbide. Also, apertures 575 and 577-579
are for mounting the blade assembly on a tool body 162 or 362.
Blade assembly 572 has been shown to penetrate hard formations at a
fast drilling rate, as well as enabling some corrective steering
action in those formations. In this hard formation application, as
was mentioned herein, it is desirable to have the forwardmost point
on strip 584A on the longitudinal axis X--X of drill pipe 42 in
order to prevent the tool body from being rotated eccentrically
around the center of bit rotation. In order to steer in soft rock,
it takes an operating technique of intermittent rotating and
thrusting. With this technique, directional blade assembly 572
allows a selective chipping away of the face of the borehole in
order to begin deviating in the desired direction.
Blade assembly 772 of FIGS. 34 and 35 is a 4" wide bit having hard
facing carbide strips 784 and 788 at forward point or tip 772A and
carbide strips 786 and 787 all functioning and having advantages as
discussed herein. The 4" wide blade assembly is preferred for
making a larger pilot hole so that backreaming is not necessary for
a 3" to 4" conduit installation.
There can also be an assembly associated with the drill frame 18 or
118 of a boring machine for preventing rotation of a drill pipe 42
having wrench receiving slots 43 as shown in FIG. 9. The assembly
includes wrench 238A of FIG. 15A having an open end for removably
engaging wrench receiving slots 43 of a rearward portion of a lower
or first drill pipe. Also, included is pin 237 received in
apertures of both the wrench and the frame and disposed adjacent
forward end 118A of the frame for attaching wrench 238 to the
frame. When the wrench engages the drill pipe, the lower or first
drill pipe is substantially prevented from rotation.
With this preferred structure, a method of breaking a joint between
drill pipe 42 and rotary drive 24 with saver sub 232 can include
the steps of moving saver sub 232, which is joined to drill pipe
42, to a forward portion in drill frame 18 or 118. This joint
breaking method then includes placing lower joint wrench 238, which
is attached to the frame and adjacent a forward end 118A of the
frame, in wrench receiving slots 43 on drill pipe 42 to
substantially prevent rotation of the drill pipe, and using rotary
drive 24 to rotate saver sub 232 in a reverse direction to unscrew
saver sub 232 from drill pipe 42.
The method of adding a second drill pipe between saver sub 232 and
a first drill pipe 42 includes breaking a joint between first drill
pipe 42 and saver sub 232 as discussed in the prior paragraph. The
method further includes the steps of moving saver sub 232 to a
rearward portion in drill frame 18 or 118, placing a second or
intermediate drill pipe in the frame between saver sub 232 and the
lower or first drill pipe, threading a male end of the second or
intermediate drill pipe into the saver sub, aligning a female end
of the second drill pipe with a male end of the first drill pipe,
moving the second drill pipe forward until a female end of the
second drill pipe fits around a male end of the first drill pipe
and applying rotational torque to tighten the rotating second drill
pipe with the stationary first drill pipe. This method can further
include the steps of a slight reversing rotation to relieve
pressure on joint wrench 238 and removing the joint wrench from
wrench receiving slots 43 of the first drill pipe 42.
Preferably an open end of wrench 238 is at a first end of the
wrench and a pin receiving aperture 239 of the wrench is at an
opposite second end of the wrench so that the wrench can be rotated
into engagement with the wrench receiving slots of the drill pipe.
In addition, it is preferable that the wrench can be slid on pin
237 in a direction parallel to a centerline of drill pipe 42 for
easy alignment with drill pipe receiving slots 43.
A second wrench 238' is also preferred for removing a second drill
pipe from between a first drill pipe and saver sub 232 as would be
required when withdrawing the drill string from the borehole. The
second wrench 238' also has aperture 239' for receiving pin 237'
which attaches the second wrench to frame 18 or 118. The second
wrench is closer to rearward end 18B or 118B of the frame than to
forward end 18A or 118A of the frame. A preferred method for
removing a second drill pipe from between a first drill pipe and
saver sub 232 includes the steps of moving rotary drive 24 to a
substantially rearward position in drill frame 18 or 118 so that
wrench receiving slots on a rearward portion of the first drill
pipe are adjacent a forward end of the frame and the second or
intermediate drill pipe is disposed on the frame between the saver
sub and the first or lower drill pipe. This method then includes
placing a first joint wrench 238, which is attached to the frame
and adjacent forward end 18A or 118A of the frame, in wrench
receiving slots 43 of the first drill pipe to substantially prevent
rotation of the first drill pipe. The next preferred step includes
securing the second drill pipe to saver sub 232 to ensure that the
joint of the second drill pipe to the first drill pipe will loosen
before the joint of the second drill pipe to the saver sub when
rotational torque is applied to the second drill pipe. It is
preferred that a lock be applied between the saver sub and the
second drill pipe so that this joint does not break before the
joint between the second drill pipe and the lower first drill pipe
is broken. One can, however, use additional torque applied by a
hand held pipe wrench on the second drill pipe to accomplish this
same function, i.e., to insure that the lower joint is broken
first.
The method then includes applying a rotational torque to the second
drill pipe which is sufficient to loosen the second drill pipe from
the first drill pipe. After applying this rotational torque, one
can then unsecure the second drill pipe from the saver sub. The
method then includes rotating the saver sub and the second drill
pipe in a reverse direction to unscrew the second or intermediate
drill pipe from the first or lower drill pipe. Further steps
include placing second joint wrench 238' which is attached to the
frame, in wrench receiving slots on a rearward portion of the
second drill pipe to substantially prevent rotation of the second
uppermost drill pipe, and rotating the saver sub in a reverse
direction to unscrew the saver sub from the second drill pipe.
Additional steps in removing a second drill pipe can include
removing second joint wrench 238' from the wrench receiving slots
of the second drill pipe and removing the second drill pipe from
the frame. Further steps can include moving rotary drive 24 forward
in the frame, rotating the saver sub to join it with the first
drill pipe and, removing the first joint wrench from the wrench
receiving slots of the first drill pipe. To remove additional drill
pipes, these above recited steps can be repeated.
Having a joint wrench attached to the frame provides advantages in
safety, simplicity and economy. Safety is attained because
attaching the wrench to the frame alleviates the prior worry about
the wrench being accidentally loosened if, for example, the drill
pipe accidentally rotates in an opposite direction than desired.
Also, by using this fixed wrench assembly, one eliminates the
complex hydraulic systems and the need for another valve section as
would be required for a powered break-out wrench.
All patents and applications mentioned in this specification are
hereby incorporated by reference in their entireties. In addition,
the structures described in this specification and claimed are
preferably used with structures disclosed in U.S. patent
application Ser. Nos. 07/539,851; 07/539,699; 07/539,551;
07/539,847; 07/539,616; 07/513,186; and 07/513,588 which are also
hereby incorporated by reference in their entireties.
With reference now to FIGS. 36-55, a number of bits suitable for
use with the boring machine will be described. These bits will be
used for horizontal and near horizontal drilling as well as
vertical drilling. FIGS. 36 and 37 illustrate a bit 600. The bit
has a body 602 which defines a rearward end 604 for attachment to
the drill string and a forward end 606 facing the ground to be
bored.
The portion of the body adjacent the rearward end 604 can be seen
to have a hexagonal cross-section perpendicular to the axis of
rotation 608 of the bit. The body defines six parallel surfaces
610-620 which each extend parallel the axis 608. Outer edges
622-632 are defined at the intersection of the parallel surfaces as
illustrated.
Three angled surfaces 634, 636 and 638 are defined on the body and
extend from intermediate the rearward and forward ends to the
forward end 606. Each of the surfaces 634, 636 and 638 are at an
angle relative to the axis 608. The orientation of the angled
surfaces can be defined relative to a hypothetical framework 640
(illustrated in FIG. 39) which is defined as if the parallel
surfaces 610-620 of the body extended all the way to the forward
end 606. The angled surfaces 634 and 638 can be seen each to
intersect two of the hypothetical parallel surfaces, specifically
parallel surfaces 610 and 612 in the case of angled surface 634 and
parallel surfaces 618 and 620 in the case of angled surface 638. It
is also helpful to define a plane of symmetry 601 (not shown) which
contains axis 608 and divides the drill bit 600 into two mirror
image halves. Each angled surface 634 and 638 is a mirror image of
the other relative the plane of symmetry 601. Angled surface 636,
in turn, will intersect a total of four parallel surfaces,
specifically surfaces 612-618. Angled surface 636 also is bisected
by the plane of symmetry 601. The intersection of the angled
surfaces and the actual parallel surfaces will define a series of
edges 642-660 between the various intersecting surfaces, each one
of those edges being at an angle relative to the axis 608.
The bit 600 has numerous advantages in the drilling operation. Each
of the edges 622-632 and 642-660 are potential cutting surfaces to
cut the ground. The angled surfaces 634, 636 and 638 define an area
as the drill bit is thrust forward which causes the drill bit to be
deflected in a new direction. The area is a compaction area during
thrust and simultaneous rotation. Further, the inclined surfaces
634-638 define incline planes that, as the bit is rotated and
thrust forward simultaneously, permit the surfaces 634-638 to work
in conjunction with cutting edges 642-660 to cut the periphery of
the borehole and simultaneously compact the material into the bore
wall or pass the cuttings through the relief areas defined by the
borehole and surfaces 610-620. Further, the use of a hexagonal
cross-section defined by the surfaces 610 through 620 will further
define an additional relief area as the drill bit is rotated
bounded by the surfaces and the cylindrical bore cut through the
ground. This additional relief area will also assist steering of
the bit. As the drill bit is rotated to form a borehole, the bit
will define a cylindrical borehole of diameter determined by the
radial dimension between the axis of rotation 608 and the edges
622-632. When the bit rotation is halted to steer the bit into a
new direction, voids exist between the inner surface of the
borehole and the surfaces 610-620, providing this additional area
to more easily deflect the bit into the new direction of drilling.
It also has a stabilizing effect to maintain a truer line (course)
while making corrections to a new base path.
With reference now to FIGS. 38 and 39, a bit 680 is illustrated
which is in all respects identical to bit 600 with the exception of
the addition of two carbide cutting tips 682 and 684. The carbide
tip 682 is positioned to extend outwardly from about the center of
surface 636 and near axis 608. The carbide tip 684 is at the
forward end 606. As the bit 680 rotates, the carbide tips will
define cutting circles established by radial distance between the
rotational axis 608 and the individual tip. Tip 682, being closer
to axis 608, defines the inner cutting circle. Tip 684, at the
outer portion of the bit, defines the outer cutting circle. The
tips 682 and 684 assist in boring, particularly in cutting through
hard soil conditions.
FIGS. 40 and 41 illustrate a bit 690 which is a modification of bit
600. In bit 690, angled surfaces 692, 694 and 696 are positioned on
the bit with the surface 694 intersecting five of the six parallel
surfaces. The plane of symmetry 698 bisects parallel surface 614
and the angled surface 694. The surfaces define angled outer edges
702-714. The distance between edges 702 and 714 and the edges 706
and 708 are greater in bit 690 than the corresponding distance in
bit 600, which makes the surface 694 wider and the bit more
appropriate for boring in softer soils. It is expected that bit 690
will be easier to direct in soft soils because of the width of the
surface 694 and the greater surface area of the angled surface
694.
With reference to FIGS. 42 and 43, a bit 710 is illustrated which
is a slight modification of bit 690. In bit 710, the angled
surfaces 712 and 716 are at a slighter greater angle relative to
the plane of symmetry 718 than those of bit 690. It would be
expected that bit 710 would be more effective in medium soils than
bit 690.
With reference now to FIGS. 44 and 45, a bit 720 is illustrated
which is formed with angled surfaces 722-728. Angled surfaces 722
and 724 are on a first side of the plane of symmetry 730. Each of
the surfaces 724 and 726 intersect three of the parallel surfaces,
while angled surfaces 722 and 728 each intersect two of the
parallel surfaces. The surfaces define angled outer edges 732-756.
Bit 720 would be intended primarily for clay and harder soils.
FIGS. 46 and 47 illustrate a bit 780. Bit 780 has a body 782 with a
circular cross-section perpendicular the axis 608. A plane of
symmetry 784 passes through the bit, intersecting axis 608, to
divide the bit into two equal mirror halves. Angled surfaces 786
and 788 are formed on the bit 780 on either side of the plane of
symmetry. Because of the circular cross-section of the bit, the
surfaces 786 and 788 will define curved edges 790 and 794, and
linear edge 792. Bit 780 would also be intended primarily for clay
and harder soils.
FIGS. 48 and 49 illustrate a bit 800 which is a modification of bit
780. Bit 800 includes a third angled surface 802 which bisects the
plane of symmetry to form linear edges 804 and 806 and a curved
edge 808.
FIGS. 50 and 51 illustrate a bit 820 which has a triangular
cross-section perpendicular the axis of rotation 608. The bit
defines parallel surfaces 822, 824 and 826. A plane of symmetry 828
is defined through the bit 820 which divides the bit into mirror
image halves. Angled surface 830 is formed on one side of the plane
while an angled surface 834 is formed on the other side of the
plane. An angled surface 832 bisects the plane of symmetry between
the surfaces 830 and 834. The surfaces define slanted outer edges
836-850.
FIGS. 52 and 53 illustrate a bit 860 which has a generally square
cross-section perpendicular the axis 608 defining parallel surfaces
862-868. Angled surfaces 870-880 are formed to define angled edges
882-900. It should be noted that bit 860 does not have a plane of
symmetry, defining two parallel surfaces 902 and 904 on one side of
the bit.
With reference to FIGS. 54 and 55, a bit 920 is illustrated which
has a tapered wedged shape. The bit includes parallel surfaces 922,
924 and 926 and angled surface 928.
With reference to FIG. 59, a bit 980 is illustrated which has
parallel surfaces 982, 984, 986 and 988 and an angled surface 990.
The front end of the bit 992 is perpendicular parallel surfaces
982-988 and is formed at the intersection of parallel surfaces 982
and 988 and angled surface 990. The angled surface 990 preferably
extends at an angle of about 20.degree. from the rotational axis of
the bit.
With reference now to FIG. 56, a drill bit 950 is illustrated which
has a body 952 with a circular cross-section perpendicular the axis
608. A curved surface 954 is formed on the drill bit which extends
from near the rear end 604 to the forward end 606. Carbide cutting
tips 956 and 958 are mounted along the drill bit to aid in cutting
with the same cutting action as described in bit 680.
With reference to FIG. 57, a drill bit 960 is illustrated which has
a prong 962 which extends outward from the curved surface 964. A
carbide cutting tip 966 is mounted at the end of the prong 962 and
a carbide cutting tip 968 is mounted at the end 606 of the drill
bit to provide the same cutting action as described in bit 680.
With reference to FIG. 58, a drill bit 970 is disclosed which has a
prong 972 extending from surface 974. A carbide cutting tip 976 is
mounted at the end of prong 972, a carbide cutting tip 978 is
mounted at the end 606 of the drill bit to provide the same cutting
action as described in bit 680.
With reference now to FIGS. 60-62, a directional multi-blade boring
head 1000 will be described. The head 1000 is mounted at the end of
a drill string which is capable of selectively rotating the head
about its central axis of rotation 1002 and advancing the head
along the axis 1002. The head includes a body 1004 which is
attached to the end of the drill string in a conventional manner.
The body defines a first planar surface 1006 on a first side of the
body and a second planar surface 1008 on the other side of the
body. The planar surfaces are both angled in an oblique angle,
preferably 13.degree., relative to the axis 1002. A jet recess 1010
is cut from the first planar surface 1006 and mounts a jet 1012 to
discharge a fluid to assist in the boring action.
As can best be seen in FIG. 62, the body has internal passages
1014, 1016 and 1018 which direct the fluid from the drill string to
the jet 1012. The fluid can be air, water, gas or any suitable
drilling fluid. As can be seen, a check valve 1020 is provided
within the passages which includes a check ball 1022 and a spring
1024 to urge the check ball into a closed position unless the fluid
pressure in passage 1018 acting on the ball is sufficient to
overcome the force of the spring 1024.
A blade assembly 1026 is mounted to the body at the second planar
surface 1008. Preferably, the blade assembly 1026 is bolted to the
body by bolts 1028 to permit the body assembly to be removed for
repair or replaced by a new blade assembly when necessary.
The blade assembly 1026 is formed of at least three blades,
including a first blade 1030, a second blade 1032 and at least one
intermediate blade 1034.
The first blade 1030 defines a deflecting surface 1036 and the
second blade defines a similar deflecting surface 1038. The
deflecting surfaces extend at an oblique angle relative to the axis
1002, preferably 13.degree.. These deflecting surfaces act to
deflect the head when the drill string to which the head is
attached is thrust forward without rotation. Thus, the head 1000
acts as a directional boring head in the manner of the bits and
heads described previously.
The first and second blades 1030 and 1032 also define staggered
cutting teeth 1040 to assist the boring action. The included angle
.theta. between the first and second blades is preferably about
120.degree.. The intermediate blade 1034 extends between the
deflecting surfaces 1036 and 1038 at an angle .theta..sub.1 from
the first blade and at an angle .theta..sub.2 from the second
blade. With the single intermediate blade 1034, the angles
.theta..sub.1 and .theta..sub.2 are preferably each
120.degree..
Each of the teeth 1040 are staggered in the direction of rotation
of the head for more effective cutting. Also, carbide cutting
elements 1041 form the part of the teeth exposed to the greatest
wear to lengthen the service life of the blade assembly 1026.
With reference now to FIGS. 63-65, a directional multi-blade boring
head 1050, forming a modification of the invention, is illustrated.
A number of the elements of boring head 1050 are identical to those
of multi-blade boring head 1000. These elements have been
identified by the same reference numerals and have similar
functions to those described with reference to head 1000.
However, the included angle .theta. between the blades 1030 and
1032 is 180.degree.. A second intermediate blade 1042 extends
between the blades 1030 and 1032 on the sides of the blades
opposite the deflecting surfaces 1036 and 1038. The second
intermediate blade 1042 in effect forms a continuation of the
intermediate blade 1034 and is also provided with serrated teeth
1040 and carbide cutting elements 1041. It will be noted that the
discharge of nozzle 1012 will strike a portion of the second
intermediate blade 1042 and a recess 1054 has been formed in the
blade 1042 to redirect the stream to assist in the cutting action.
The four bladed bit 1050 will permit smoother, straighter bores in
harder soil conditions while the inclined planes 1036 and 1038
provide the bit with directional capabilities.
Now with reference to FIGS. 66-68, a directional dual-cone boring
bit 1100 is illustrated. The dual cone boring bit has rotary
cutters or cones 1104 and 1105 similar to those used on prior art
Tri-cone drilling bits used in the oil field. The boring bit 1100
is used to directionally drill in hard or semi-hard materials. The
head 1100 is mounted at the end of a drill string which is capable
of selectively rotating the head about its central axis of rotation
1002 and advancing the head along the axis 1002. The head includes
a body 1004 which is attached to the end of the drill string in a
conventional manner. The body defines a first planar surface 1006
on the first side of the body and a second planar surface 1008 on
the other side of the body. The planar surfaces are both angled in
an oblique angle, preferably 13 degrees, relative to the axis 1002.
A jet recess 1010 is cut from the first planar surface 1006 and
mounts a jet 1101 to discharge a fluid such as a liquid or a gas to
assist in the boring. The jet 1101 is extended in length as
compared to jet 1012 of the previous multi-blade bits to ensure
fluid is directed at the dual cones to provide lubrication, cooling
and assist in boring. All other aspects of the fluid delivery
system are the same as boring heads 1000 and 1050.
The bit assembly 1102 is mounted to the body at the second planar
surface 1008. Preferably, the bit assembly 1102 is bolted to the
body by bolts 1103 to permit the body assembly to be removed for
repair or install a new bit assembly when necessary.
The bit is formed of two roller cones and attachment body
consisting of the center cut cone 1104 and adjacent cone 1105 from
a standard tri-cone oil field bit. The rotational axis of each of
the cones preferably intersects the axis 1002. The cones and bodies
are welded to components 1106 and 1107 to form bit assembly 1102. A
part of the bit assembly defines a deflecting surface 1108
extending at an oblique angle similar to and causing the bit to act
as a directional boring head in the manner of the bits and heads
described previously.
With reference now to FIGS. 69-.[.72.]. .Iadd.71.Iaddend., a
directional single cone boring bit 1200 is illustrated. The single
cone boring bit has a single rotary cutter or cone 1202 similar to
those used on prior art tri-cone drilling bits used in the oil
field. The jet 1101 discharges against the side of the cutter 1202
to clean debris therefrom. In other aspects, the boring bit 1200 is
identical to boring bit 1100 discussed previously and identical
elements on the figures are identified by the same reference
numerals.
The roller cones described in this invention provide the same
cutting action as in the oil field application of the tri-cone bits
previously described. These tri-cone bits have one center cut cone
and two adjacent cones. However, the addition of the deflecting
surface and the removal of one of the adjacent roller cones permits
the bit 1100 when thrust forward without rotation to be deflected
from the axis of the bore thus permitting the direction of the bore
to be altered. The addition of the deflecting surface and the
removal of two of the adjacent roller cones permits the bit 1200
when thrust forward without rotation to be deflected from the axis
of the bore thus permitting the direction of the bore to be
altered. The continuous rotation of the drill bit and application
of thrust permits the bore to be in a straight line relative to the
drill string axis 1002. The hardness of the material being cut will
dictate the amount of steering capable of being accomplished. Some
semi-hard materials will permit the oscillating of the bit and the
drill string about the central axis of rotation 1002 while applying
thrust to change the direction of the bore axis.
The heads 1000, 1050, 1100 and 1200 described have a number of
significant advantages over previous known boring heads. The heads
1000, 1050, 1100 and 1200 bore a rounder, straighter hole than a
one-sided slanted head which tends to drill more of a helical
borehole. The heads 1000, 1050, 1100 and 1200 have proven
particularly effective in boring productivity and direction
accuracy through sand and rock. With previous one-sided slanted
heads, the head could impact and catch on a hard object, causing
the boring rods in the drill string to wind up in torsion until the
head breaks free of the object with a sudden release. The heads
1000, 1050, 1100 and 1200 appear to alleviate this problem.
The additional advantages of heads 1000, 1050, 1100 and 1200
include an improvement in the directional accuracy of the head
through rock and other hard boring conditions. The boring head also
uses less water to cool the bit which has significant advantages as
EPA regulations for disposal of drilling fluids are becoming more
difficult to comply with. The presence of the blades also reduces a
tendency for the head to roll when pushed forward without rotation
to make a directional change. Finally, the head provides an
improved ease of surface launch.
While the invention has been described with a certain degree of
particularity it is manifest that many changes may be made in the
details of construction and arrangement of components without
departing from the spirit and scope of this disclosure. It is
understood that the invention is not limited to the embodiments set
forth herein for purposes of exemplification, but is to be limited
only by the scope of the attached claim or claims, including the
full range of equivalency to which each element thereof is
entitled.
* * * * *