U.S. patent number 3,554,304 [Application Number 04/798,042] was granted by the patent office on 1971-01-12 for retractable drill bits.
This patent grant is currently assigned to Christensen Diamond Products Company. Invention is credited to Harold C. Bridwell, Howard D. Link, David S. Rowley.
United States Patent |
3,554,304 |
Link , et al. |
January 12, 1971 |
RETRACTABLE DRILL BITS
Abstract
A rotary well-drilling bit lowered through drill pipe with
cutters in tandem array, the cutters being expanded outwardly and
locked to the lower end of the drill pipe to drill upon
substantially the full cross-sectional area of the bottom of the
well bore. The cutters can be pulled by a wire line device back
into the drill pipe and elevated through the drill pipe to the
drilling rig for replacement or inspection.
Inventors: |
Link; Howard D. (Salt Lake
City, UT), Bridwell; Harold C. (Salt Lake City, UT),
Rowley; David S. (Salt Lake City, UT) |
Assignee: |
Christensen Diamond Products
Company (Salt Lake City, UT)
|
Family
ID: |
25172377 |
Appl.
No.: |
04/798,042 |
Filed: |
February 10, 1969 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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583263 |
Sep 30, 1966 |
3437159 |
|
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Current U.S.
Class: |
175/259;
175/260 |
Current CPC
Class: |
E21B
10/66 (20130101) |
Current International
Class: |
E21B
10/00 (20060101); E21B 10/66 (20060101); E21b
000/26 () |
Field of
Search: |
;175/260,259,257 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Leppink; James A.
Parent Case Text
The present application is a continuation-in-part of our
application for "Retractable Drill Bits," Ser. No. 583,263, filed
Sept. 30, 1966, now Pat. No. 3,437,159.
Claims
We claim:
1. In an expansible and retractable drill bit for drilling a bore
hole: tubular drive means attachable to the lower portion of a
tubular drilling string; deflector means extending across the
passage of said drive means; cutter means movable downwardly
through the passage of said drive means and into engagement with
said deflector means to be expanded thereby into driving relation
to said tubular drive means and to a position extending laterally
outwardly beyond the exterior of said drive means; said cutter
means being constructed and arranged to extend from a location
closely adjacent to the axis of said tubular drive means to said
extended position beyond said drive means to drill upon
substantially the full cross-sectional area of the bottom of the
bore hole upon being expanded into driving relation to said tubular
drive means; and means for turning said cutter means within said
drive means in response to downward movement of said cutter means
in said drive means to orient said cutter means relative to said
deflector means.
2. In a drill bit as defined in claim 1; and holding means in said
drive means for retaining said cutter means in its outwardly
expanded position.
3. In an expansible and retractable drill bit for drilling a bore
hole: tubular drive means attachable to the lower portion of a
tubular drilling string; deflector means extending across the
passage of said drive means; cutter means movable downwardly
through the passage of said drive means and into engagement with
said deflector means to be expanded thereby into driving relation
to said tubular drive means and to a position extending laterally
outwardly beyond the exterior of said drive means; said tubular
drive means having a plurality of circumferentially spaced slots;
said cutter means comprising a plurality of cutter members movable
in tandem through the passage of said drive means and successively
into engagement with said deflector means to be deflected thereby
successively laterally into said slots and into coupling relation
to said drive means; said cutter means being constructed and
arranged to extend from a location closely adjacent to the axis of
said tubular drive means to said extended position beyond said
drive means to drill upon substantially the full cross-sectional
area of the bottom of the bore hole upon being expanded into
driving relation to said tubular drive means.
4. In a drill bit as defined in claim 3; and a plug bit secured to
the inner portion of one of said cutter members for drilling the
axial portion of the bottom of the bore hole.
5. In a drill bit as defined in claim 3; and holding means movable
downwardly in said drive means passage behind said cutter means to
retain said cutter means within said slots in their outwardly
expanded position.
6. In a drill bit as defined in claim 3; and orienting means for
aligning said cutter means with said slots to insure their outward
deflection thereinto.
7. In a drill bit as defined in claim 3; orienting means for
aligning said cutter means with said slots to insure their outward
deflection thereinto; and holding means movable downwardly in said
drive means passage behind said cutter means to retain said cutter
means within said slots in their outwardly expanded position.
8. In a retractable and expansible drill bit: tubular drive means
attachable to the lower portion of a tubular drilling string;
deflector means rigidly fixed to said drive means and extending
across the passage of said drive means; and cutter means movable
downwardly through the passage of said drive means from a position
completely above said deflector means and into engagement with said
deflector means to be expanded thereby into driving relation to
said tubular drive means and to a position extending laterally
outwardly beyond the exterior of said drive means.
9. In a drill bit as defined in claim 8; said cutter means being
constructed and arranged to extend from a location closely adjacent
to the axis of said tubular drive means to said extended position
beyond said drive means to drill upon substantially the full
cross-sectional area of the bottom of the bore hole upon being
expanded into driving relation to said tubular drive means.
10. In a drill bit as defined in claim 8; said tubular drive means
having a plurality of circumferentially spaced slots; said cutter
means comprising a plurality of cutter members movable in tandem
through the passage of said drive means and successively into
engagement with said deflector means to be deflected thereby
successively laterally into said slots and into coupling relation
to said drive means.
11. In a drill bit as defined in claim 8; said tubular drive means
having a plurality of circumferentially spaced slots; said cutter
means comprising a plurality of cutter members movable in tandem
through the passage of said drive means and successively into
engagement with said deflector means to be deflected thereby
successively laterally into said slots and into coupling relation
to said drive means; said cutter means being constructed and
arranged to extend from a location closely adjacent to the axis of
said tubular drive means to said extended position beyond said
drive means to drill upon substantially the full cross-sectional
area of the bottom of the bore hole upon being expanded into said
slots and into coupling relation to said drive means.
12. In a drill bit as defined in claim 8; said tubular drive means
having a plurality of circumferentially spaced slots; said cutter
means comprising a plurality of cutter members movable in tandem
through the passage of said drive means and successively into
engagement with said deflector means to be deflected thereby
successively laterally into said slots and into coupling relation
to said drive means; said cutter members being constructed and
arranged to extend from a location closely adjacent to the axis of
said tubular drive means to said extended position beyond said
drive means to drill upon substantially the full cross-sectional
area of the bottom of the bore hole upon being expanded into said
slots and into coupling relation to said drive means; and a plug
bit secured to the inner portion of one of said cutter members for
drilling the axial portion of the bottom of the bore hole.
13. In a retractable and expansible drill bit for drilling a bore
hole: tubular drive means attachable to the lower portion of a
tubular drilling string, said tubular drive means having a
plurality of circumferentially spaced slots; deflector means
rigidly fixed to said drive means and extending across the passage
of said drive means, said deflector means being disposed adjacent
said slots; carrier means adapted to be lowered and elevated
through the drilling string on a wire line; cutter means carried by
said carrier means and comprising a plurality of cutter members
movable in tandem through the drilling string and drive means
passage and successively into engagement with said deflector means
to be expanded thereby successively laterally into said slots to
extend beyond said drive means in coupling relation to said drive
means; said carrier means being movable downwardly in said drive
means passage behind said cutter means to retain said cutter
members in coupling relation to said drive means.
14. In a drill bit as defined in claim 13; said cutter members
having fluid passages therein for discharging drilling fluid toward
the bottom of the bore hole; said carrier means having a central
fluid passage communicating with said fluid passages when said
carrier means is behind said cutter means.
15. In a drill bit as defined in claim 13; said cutter members
having portions underlying and engaging said deflector means when
said cutter members are coupled to said drive means.
16. In a drill bit as defined in claim 13; said cutter members
having portions underlying and engaging said deflector means when
said cutter members are coupled to said drive means; said cutter
members having fluid passages therein for discharging drilling
fluid toward the bottom of the bore hole; said carrier means having
a central fluid passage communicating with said fluid passages when
said carrier means is behind said cutter means.
17. In a drill bit as defined in claim 13; and orienting means
within said drive means for aligning said cutter members with said
slots to insure their outward expansion thereinto.
18. In a drill bit as defined in claim 13; said cutter members
being constructed and arranged to extend from a location closely
adjacent to the axis of said tubular drive means to said extended
position beyond said drive means to drill upon substantially the
full cross-sectional area of the bottom of the bore hole upon being
expanded into driving relation to said tubular drive means.
19. In a drill bit as defined in claim 13; said cutter members
being constructed and arranged to extend from a location closely
adjacent to the axis of said tubular drive means to said extended
position beyond said drive means to drill upon substantially the
full cross-sectional area of the bottom of the bore hole upon being
expanded into driving relation to said tubular drive means; and a
plug bit secured to the inner portion of one of said cutter members
for drilling the axial portion of the bottom of the bore hole.
20. In a drill bit as defined in claim 13; said cutter members
being constructed and arranged to extend from a location closely
adjacent to the axis of said tubular drive means to said extended
position beyond said drive means to drill upon substantially the
full cross-sectional area of the bottom of the bore hole upon being
expanded into driving relation to said tubular drive means; said
cutter members having fluid passages therein for discharging
drilling fluid toward the bottom of the bore hole; said carrier
means having a fluid passage communicating with said fluid passages
when said carrier means is behind said cutter means.
21. In a drill bit as defined in claim 13; said cutter members
being constructed and arranged to extend from a location closely
adjacent to the axis of said tubular drive means to said extended
position beyond said drive means to drill upon substantially the
full cross-sectional area of the bottom of the bore hole upon being
expanded into driving relation to said tubular drive means; said
cutter members having fluid passages therein for discharging
drilling fluid toward the bottom of the bore hole; said carrier
means having a fluid passage communicating with said fluid passages
when said carrier means is behind said cutter means; said cutter
members having portions underlying and engaging said deflector
means when said cutter members are coupled to said drive means.
Description
The present invention relates to rotary bits for drilling bore
holes, and more particularly to rotary bits which are retrievable
and replaceable by movement through a string of drill pipe
extending to the drilling rig, obviating the need for withdrawing
the drill pipe string from the bore hole each time the drill bit is
to be removed for replacement or inspection.
In the rotary drilling of well bores, and similar bore holes, the
usual practice is to secure a rotary drill bit to the lower end of
a string of drill pipe and lower such pipe to the bottom of the
bore hole for continued drilling of the hole. Dulling of each bit
requires removal of the entire string of drill pipe to the drilling
rig, removal of the dull bit, the attaching of another bit to the
drill string, and relowering of the latter in the bore hole to its
bottom. The necessity for "round tripping" the drill pipe for
changing bits is a relatively slow and costly operation in view of
the time consumed, the cost increasing as the depth of the hole
increases and the string of drill pipe becomes longer. The cost of
round tripping is quite considerable in offshore drilling of bore
holes, in view of the very high hourly rate of operating a drilling
platform, or a drilling vessel or barge floating in the ocean or
other body of water.
It has been proposed to avoid the costly round tripping of the
drill pipe for the purpose of changing drill bits by providing bits
of the type that can be moved through the string of drill pipe,
being latched in the lower portion of the latter for the
performance of the rotary drilling operation, and being released
from the drill pipe when the drill bit is to be replaced. The prior
devices have not been successful, since the drill bit cutters are
relatively small, placing limitations on the diameter of the hole
which they can drill effectively. This is particularly true where
the minimum diameter of the passage through the drill pipe string
is relatively small.
It is an object of the present invention to provide an improved
rotary drill bit of the type capable of being lowered and removed
through a string of drill pipe, or other drill string, and which
overcomes the above-noted disadvantages, the drill bit being
capable of drilling the full cross section of the bore hole.
Another object of the invention is to eliminate the need for slow
round trips with the drill pipe to change the drill bits capable of
operating upon the entire bottom of the bore hole, thereby reducing
considerably the time required for changing drill bits, with
resultant major economies in drilling of the bore hole.
Yet another object of the invention is to provide a drill bit
mechanism which embodies relatively large bit members movable
through the drill pipe, and capable of being positively locked in
expanded condition to the rotatable main body or drive mandrel of
the bit, to drill the full cross-sectional area of a bore hole
substantially greater in diameter than the outside diameter of the
drill pipe disposed in the bore hole. As an example, the bit
members can pass through a drill pipe string of about 4 inches
inside diameter, or through a hollow shaft turbine for rotating the
drill bit having an inside diameter of about 4 inches, and be
capable of drilling a 97/8 inch diameter hole when locked to the
drive mandrel of the drill bit mechanism.
A further object of the invention is to provide a drill bit
mechanism capable of movement through a string of drill pipe and
withdrawal therethrough to the drilling rig, capable of drilling
the full cross-sectional area of a bore hole more than twice the
diameter of the minimum bore through the drill pipe or hollow shaft
of a turbine through which the retractable bit members can
pass.
Another object of the invention is to provide a rotary drill bit of
the type above indicated for drilling upon substantially the entire
bottom of the bore hole, in which the individual bit members are
properly oriented upon reaching the vicinity of the rotatable drive
member at the lower end of the drill string, to insure their
correct alignment with the mandrel slots into which they are
expandable into appropriate coupled relation to the mandrel, for
the transmission of torque and drilling weight between the mandrel
and the individual bit members.
Another object of the invention is to positively block or lock the
bit cutter members of a full cross section drilling bit in their
outwardly expanded condition in the drive mandrel secured to the
lower end of the drill string, to prevent horizontal or radial
forces incident to the drilling operation, such as drilling weight
transmitted through the bit members, from shifting the bit members
inwardly. Similarly, drilling weight and drilling torque imposed on
the bit members through the drive mandrel cannot effect their
inward shifting from their expanded position, the drilling weight
and torque being transmitted directly between the drive mandrel and
bit members.
Yet a further object of the invention is to provide a bit of the
type above indicated, through which adequate drilling fluid can be
circulated for removal of cuttings and for maintenance of the bit
members in a clean and cool condition.
This invention possesses many other advantages, and has other
objects which may be made more clearly apparent from a
consideration of a form in which it may be embodied. This form is
shown in the drawings accompanying and forming part of the present
specification. It will now be described in detail, for the purpose
of illustrating the general principles of the invention; but it is
to be understood that such detailed description is not to be taken
in a limiting sense.
Referring to the drawings:
FIGS. 1, 1a and 1b together constitute a longitudinal section
through the apparatus, with portions shown in side elevation, with
parts of the apparatus in condition for movement through its outer
portion, FIGS. 1a and 1b being lower continuations of FIGS. 1 and
1a, respectively;
FIGS. 2 and 2a are views corresponding to FIGS. 1, 1a and 1b,
showing the parts locked in position within the outer or driving
portion of the apparatus, FIG. 2a constituting a lower continuation
of FIG. 2;
FIGS. 3, 3a and 3b are views, on an enlarged scale, corresponding
to FIGS. 1, 1a and 1b, FIGS. 3a and 3b being lower continuations of
FIGS. 3 and 3a, respectively;
FIGS. 4 and 4a are views, on an enlarged scale, corresponding to
FIGS. 2 and 2a, FIG. 4a being a lower continuation of FIG. 4;
FIG. 5 is a cross section taken along the line 5-5 on FIG. 3a;
FIG. 6 is a cross section taken along the line 6-6 on FIG. 4;
FIG. 7 is a cross section taken along the line 7-7 on FIG. 4a;
FIG. 8 is a cross section taken along the line 8-8 on FIG. 4a;
FIG. 9 is a cross section taken along the line 9-9 on FIG. 4a;
FIG. 10 is an isometric projection, with parts broken away, of the
orienting sleeve;
FIG. 11 is a diagrammatic view in a single plane (not to scale) of
the orienting sleeve disclosed in FIG. 10;
FIG. 12 is a plan view as seen from the bottom of FIG. 3b;
FIG. 13 is a plan view as seen from the bottom of FIG. 4a;
FIG. 14 is an isometric view of the drive mandrel of the bit;
FIG. 15 is an isometric view, on an enlarged scale, of the central
plug bit to be secured to one of the bit pads;
FIG. 16 is a fragmentary vertical section, on an enlarged scale, of
one of the cutter assemblies locked in position within the drive
mandrel; and
FIG. 17 is an enlarged isometric view of one of the bit pads, as
seen from the inner side thereof.
The specific retractable drill bit mechanism illustrated in the
drawings is capable of drilling a bore hole and is movable as a
unit through a string of drill pipe A between the drilling rig and
the lower portion of the hole. The drill bit members are movable
together through the drill string extending to the drill rig. The
drill bit members are secured to the lower portion of the drill
string, and the drilling weight and drilling torque are transmitted
to it through rotation of the drill string, or, if desired, of a
prime mover mechanism, such as a fluid-operated turbine (not
shown), which may be incorporated in the drill string near the
lower portion thereof for rotating the drilling mechanism, this
fluid-operated turbine having a hollow rotor shaft of an
appropriate inside diameter through which the retractable drill bit
members can pass in being moved into the lower portion of the
drilling apparatus and in being released and retracted
therefrom.
As specifically illustrated in the drawings, the drill bit
mechanism includes a lower drive mandrel 10 having a plurality of
circumferentially spaced slots 11 extending through its wall into
which drill bit pads or cutter members 12 are shifted to extend
laterally outwardly beyond the periphery of the drive mandrel or
main body member 10 of the drill bit. As disclosed in the drawings,
there are three slots 11 in the drive mandrel, and three drill bit
pads or cutter members, one for each slot, expandable into the
slots to be locked to the drive mandrel, and which are also
retractable from the slots. Each drill bit member 12 and its
associated mechanism described hereinbelow are of a size capable of
passing through the inside diameter of the drill string A and
through the hollow rotor shaft of a turbine (not shown), if one is
employed as the motive power mechanism for rotating the retractable
rotary drill bit.
Each drill bit pad or cutter 12 has its upper end pin connected to
a link 13, which, in turn, is pin connected to a pad or cutter
follower 14 suitably secured to the lower end of a wire cable 15,
as by silver soldering, the upper end of which is suitably secured,
as by silver soldering, to the lower end of a rod 16, which may be
round in cross section and made of steel, extending upwardly within
the drive mandrel 10 and adjacent to its inner wall. Each follower
14 has a bar portion 17 loaded by a spring 17a to extend outwardly
and ride within a longitudinal groove 19 in the inner wall of the
drive mandrel to orient each associated pad 12 with a mandrel slot
11, this groove being wider at its lower end 20 where it is
inclined in a downward and outward direction within the drive
mandrel and opens into the upper end of the mandrel slot 11. Since
there are a plurality of bit cutters or pads 12 (three in the
specific apparatus illustrated in the drawings), there is a link
13, pad follower 14, wire cable 15, round steel rod 16, bar portion
17, and spring 17a associated with each pad. In other words, there
are three sets of pads, links, followers, cables, steel rods, bar
portions and springs, the sets being circumferentially spaced from
one another about 120.degree..
A plug bit 18, FIGS. 15 and 16, is suitable secured to the inner
end cutting portion of one of the drill bit pads 12, as by use of a
bolt 18a. This plug bit will be located at the tool axis to fill
the opening or space formed by adjoining drill bit pads 12 when
they are assembled in the drive mandrel 10, eliminating the problem
of a central core being formed in the formation when drilling.
The drive mandrel has an upper threaded pin 20a threadedly secured
to a companion box 21 of an elongate drive barrel 22 having an
upper pin thread 23 for threaded attachment to the lower end of an
adjacent drill string member A, which may either be a drill collar,
or the rotor of a turbine secured in the drill string. The rotation
of the drill string or turbine A is transmitted through the drive
barrel 22 to the drive mandrel 10, and from the latter to the
cutter pads 12 when they are locked in position within the mandrel
slots 11, as described hereinbelow.
Mounted within the lower portion of the drive barrel 22 is an
orienting sleeve 24 having a plurality of circumferentially spaced,
longitudinal orienting grooves 25 (FIGS. 10, 11) therein in
alignment with the companion grooves 19 in the drive mandrel. Since
three sets of cutter mechanisms are employed to be disposed
120.degree. apart, the orienting sleeve grooves 25 are spaced
120.degree. apart and are aligned with three grooves 19 spaced
120.degree. apart in the drive mandrel. The alignment is obtained
by providing downwardly projecting pins 26 on the lower end of the
orienting sleeve received within companion sockets 27 in the upper
end of the drive mandrel 10.
The sets of pads 12, links 13 and pad followers 14 are movable
through the string of drill pipe A and drive barrel 22 in tandem or
series relation, which will permit the cutter pads, links, and
followers to be made of substantial size, being only slightly
smaller in maximum transverse dimension than the minimum diameter
through the drill string A, orienting sleeve 24 and drive mandrel
10. To enable such series or tandem movement to take place, the
longitudinal supporting rods 16 are made of different lengths, and
these rods each have upper heads 35, such as T-shaped heads,
adapted to rest against the lower ends or shoulders 36 of
circumferentially spaced elongate grooves 37 formed in the
periphery of the carrier barrel 38 of the drilling mechanism, the
bottom of each groove being flat and having a half-circular recess
39 therein in which the elongate rod 16 can move, this rod also
extending slidably through a companion recess 40 in the lower
portion of the carrier barrel 38 below its groove 37.
Thus, during lowering of the drilling mechanism and the cutter
devices through the string of drill pipe A and its elevation
therethrough, the T-shaped heads 35 rest upon the carrier barrel
shoulders 36. The uppermost set of a pad 12, link 13 and pad
follower 14 is connected through the wire cable 15 to a rod 16 of
relatively short length, the intermediate set to a rod of longer
length, so that such set can hang below the uppermost set, the
lowermost set being suspended from a steel rod 16 of a
substantially greater length than the intermediate rod, so that
such set will remain suspended below the intermediate pad 12. As
described hereinbelow, when the pads are expanded outwardly in the
drive mandrel slots 11 and are locked in position, the carrier
barrel 38 will move downwardly behind the sets of cutter members
12, 13, 14, the carrier barrel 38 sliding downwardly along the rods
16, the heads 35 of which are free to move relatively upwardly
within the longitudinal grooves 37.
The drill bit mechanism, as stated above, is movable through the
drill pipe string A and through the drive barrel 22. The carrier
barrel 38 is threadedly attached to an adapter coupling 42 (FIG. 3)
threadedly secured to a latch body 43 at its upper end, its lower
end having ports 44. Seals 41, secured to the barrel 38 at the port
outlets, are adapted to align with flow passages 45 extending
through the drill bit pads 12 to provide a continuation of the
fluid passage 47 in the carrier barrel 38 for the drilling fluid
used for circulating the cuttings from the bore hole and for
cleaning and cooling the bit cutter members, as described
hereinbelow.
The drill bit mechanism is releasably latched to the drive barrel
22. Such releasable latch device includes the latch body 43
previously described, which has a single transverse slot 64
therethrough through which a laterally shiftable latch member 65 is
slidable. This latch has inwardly directed parallel side arms 66
extending into side grooves 67 in a retracting rod 68 slidable
longitudinally in the latch body 43, helical compression springs 69
engaging the inner ends of these arms and bearing against the latch
body to urge the latch 65 in an outward direction. The retracting
rod 68 is prevented from turning within the latch body 43 by a pin
70 shiftable in a longitudinal latch body slot 71, the retracting
rod 68 having retracting pins 72 extending laterally therefrom and
received within slots 73 in the latch arms, the inner side of each
slot having a tapered or cam face 74 inclined in an upward and
outward direction to be engaged by its associated retracting pin
72, upon upward movement of the retracting rod, to shift the latch
65 inwardly completely from its companion circumferential groove 75
in the drive barrel 22, thereby to release the drilling
mechanism.
The retracting rod 68 is normally urged in a downward direction by
a helical compression spring 76 bearing against a cap 77 threadedly
secured within the upper end of the latch body 43, the lower end of
the spring bearing against a retracting rod flange 78. When the
retracting rod is in its downward position, its pin 70 bears
against a ring 79, which forces a rubber or rubberlike seal ring 80
against a sleeve 81 encompassing the adapter coupling 42, the
sleeve being urged against the seal ring by a helical compression
spring 82 bearing against the sleeve and against an external
shoulder 83 on the adapter coupling. The pliant, elastic seal ring
80 has an unrestrained external diameter slightly less than the
internal diameter of the drive barrel 22. However, when the
retracting rod 68 is disposed in its lowermost position, with its
pin 70 bearing against the ring 79, in order to shift the latter
toward the sleeve 81 and compress the seal ring 80, the latter is
expanded outwardly into sealed relation against the inner wall of
the drive barrel 22 to prevent leakage of fluid along such
wall.
The circulating fluid used in drilling can flow through the drill
pipe string A and into the upper end of the drive member 22,
passing through ports 84 in the retracting rod 68 to its central
passage 85, and flowing therefrom through the latch body 43 into
the adapter coupling 42, and into the fluid passage 47 or bore of
the carrier barrel 38.
The retracting rod 68 has an upper head 91 adapted to be engaged by
a suitable overshot 92 secured to a wire line 93, by means of which
the entire mechanism is lowered through the drill pipe string A and
into the drive member 22 and drive barrel 10, and is also withdrawn
therefrom. The lowering will occur until the final latch 65 expands
outwardly into its companion groove 75 in the drive barrel 22, at
which time a suitable telemeter microswitch 94 on the retracting
rod 68 will be closed and convey a signal through the electrically
conductive wire line 93 to the drilling rig, advising the operator
that the mechanism has been latched in final position. Similarly,
elevation of the wire line 93 with its overshot 92 connected to the
head 91 will elevate the retracting rod 68 and cause its pins 72 to
retract the latch 65 from the groove 75, which will be accompanied
by suitable actuation of the telemeter microswitch, advising the
operator that the mechanism has been unlatched and is in a
condition to be released from the drive mandrel 10 for withdrawal
through the string of drill pipe A to the top of the bore hole.
The drill bit members arranged in tandem suspension from the
carrier barrel 38 through the agency of the rods 16 are lowered
through the passage in the string of drill pipe A and also through
the hollow turbine rotor shaft, assuming a turbine is used in the
drill string, on the wire line 93. The drill bit pads or members 12
are suspended substantially 120.degree. from one another (since
three cutter pads are used in the specific tool shown in the
drawings) because of the fact that the suspension rods 16 are
disposed 120.degree. from one another, and these pad members 12 are
oriented with respect to the slots 11 in the drive mandrel 10 by
means of the orienting sleeve 24 and the follower orienting bar 17
serving to achieve the appropriate orienting.
Appropriate inclined guide surfaces 101, 102 are provided on the
orienting sleeve for insuring the guiding of the orienting bars 17
into the grooves 25 of the orienting sleeve 24. FIGS. 10 and 11
disclose the orienting sleeve 24, the lower longitudinal grooves 25
of which have a width slightly greater than the width of the
orienting bars 17, as described hereinabove. Each of these grooves
terminates at a window 103 having sides 101, 102 that diverge in an
upward direction. The right side 102, as disclosed in FIG. 10,
terminates at the upper end of the window or opening 103; whereas,
the left side 101 continues upwardly beyond the window, its
inclination continuing to the upper inwardly beveled surface 104 of
the orienting sleeve and constituting the left side of an upper
groove 105 opening through the upper end of the sleeve. This groove
has its left side 106 tapered from the base of the groove to the
inner surface of the sleeve 24. It is to be noted that the upper
end 107 of the left side 101 of each groove extends
circumferentially beyond the upper end 108 of the right side of an
adjacent window 103; that is, the upper left side of an inclined
guide surface 101 that is associated with one window overlaps the
right guide surface 102 of an adjacent window. Thus, the orienting
bar 17 of the lowermost set of bit members constituting the cutter
pad 12, link 13, and pad follower 14 will engage either the left or
right guide surface 101, 102 of one of the windows 103 and grooves
105 in the orienting sleeve 24 as the apparatus is being lowered
through the latter, which will turn the drill bit member 38 into a
position in which the lowermost pad 12 is in alignment with one of
the slots 11. This will substantially orient the several bars 17
with the longitudinal grooves 25 in the orienting sleeve 24.
However, if they are angularly displaced from such grooves, they
will individually engage either the right or left guide surfaces
102, 101 of the orienting sleeve, which will shift them angularly
to a position in which the bars 17 slide into the longitudinal
grooves 25, insuring the appropriate alignment of each pad 12 with
an individual slot 11 in the drive mandrel, and also into
appropriate alignment with an upwardly converging pad deflecting
cone 110 integral with and disposed centrally of the drive mandrel
10 at its lower portion, in order to deflect each pad 12 into its
individual slot 11. Downward movement of the drilling mechanism can
continue until the latch 65 expands outwardly into the latch groove
75 in the drive barrel 22, at which time the carrier barrel 38 will
be located behind the sets of pads 12 and followers 14 to lock them
in their outward position, as described in detail hereinbelow.
The drive mandrel has circumferentially spaced legs 112 which are
defined by the mandrel slots 11, the legs having cylindrical upper
portions 113 and downwardly tapering lower portions 114. The lower
portions of the legs are interconnected by an annular strut or
cutter pad locator support 115, which has the lifting cone or
deflecting cone 110 extending into the central passage 125 of the
drive mandrel 10, with longitudinal grooves or cutouts 111 in the
cone aligned with the center of the mandrel slots 11 to permit the
plug bit 18 to pass through any groove 111 into any slot 11 without
excess lift of interference of the bit pads 12. Projecting from the
sides of the struts 115 into the mandrel slots 11 are retaining
guides 116 which are adapted to extend into guide tracks 117 of the
bit pads 12 to contain the pads from extending or protruding beyond
a controlled condition.
The inside diameter formed by the followers 14 and the upper
portion of the bit pads 12 conform to the external diameter of the
carrier barrel 38, which firmly supports the follower and bit pad
mechanism s while drilling. The inside diameter of the lower
portion of the bit pads conforms to the external diameter of the
lower portion 126 of the carrier barrel 38 which is reduced in
diameter to eliminate the rod retaining grooves 40 and provide a
good mating sealing surface for the ports 44 in the carrier barrel
to the passages 45 in the bit pads.
Each cutter pad 12, when locked in expanded position within the
mandrel slot, has an upper end surface 128 which is tapered to
conform with the upper tapered outer end portion 129 of the mandrel
slot, an upper surface 130 of the pad extending downwardly from the
tapered end surface and parallel to the axis of the drive mandrel,
this upper surface being curved circumferentially to conform to the
curvature of the diameter of the well bore being drilled. The upper
parallel surface 130 of the pad or cutter member merges into a
downwardly tapering surface 131 adapted to drill a tapered bore in
the bottom of the hole, this tapered surface merging into a lower
end face or surface 132 extending inwardly toward the axis of the
drive mandrel and merging upwardly into an inner conical surface
133 to help support and stabilize the drill bit on the formation
bottom formed by the bit pads or members 12. Each pad has a
transverse upwardly facing shoulder 134 adapted to engage the
bottom of an annular strut 115, the carrier barrel 38 bottoming on
an annular strut 115 with the deflecting cone 110 contained in a
suitable conical recess 135 of the barrel 38, and with the latch
bar 65 snapping into the latching groove 75 to lock the drilling
mechanism firmly in place, which is the final latched position of
the drilling mechanism within the drive barrel 22 and mandrel
10.
Each drill bit cutter or pad 12, when locked in expanded position
within the drive mandrel 10, also has a downwardly tapering inner
surface 138 extending from its upper end, which is engaged by a
companion outer surface 139 on its pad follower 14 when the latter
is shifted outwardly against the bit pad 12, the upper end of the
pad follower engaging the inner upper tapered surface 140 of the
drive mandrel defining the upper end of the slot 11. The inner
surface 141 of the back face of the pad follower 14 is concavely
curved to conform to the periphery of the carrier mandrel 38, which
it will snugly engage, the outer surface or face 139 of the
follower also being concavely curved and conforming to a companion
convex curvature on the inclined inner surface 138 of the pad 12
(FIG. 8).
Each pad has guide tracks 117 on its inner portion, each of which
defines a downwardly opening recess with the main body of the pad
and adapted to receive a retaining guide bar 116 of the annular
strut or pad locator support 115 extending into the mandrel slot
11. As the pad 12 is being expanded outwardly to its final
position, the tracks 117 will move downwardly over the guide
portions 116 of the annular strut and the pad will swing outwardly
about this strut as a pivot until its upper portion has been swung
completely into the slot 11, and with its upper outer surface 130
parallel to the axis of the drive mandrel 10, and with its upper
end 128 engaging the upper end 129 of the slot, such as disclosed
in FIGS. 2a, 4a and 16. At this time, the retaining bars 116
extending from the sides of the struts 115 are snugly received
within the recesses of the tracks 117, the inner faces of the pads
12 conforming to the shape of the annular strut. When the pad 12 is
swung outwardly to its final position, its outer drilling surface
130 is then also extending parallel to the axis of the drive
mandrel and at the appropriate radius from such axis, and beyond
the periphery of the legs 112, so as to produce the desired
diameter in drilling the formation. When in this position, the
gasket seals 41 around the ports 44 at the lower end of the outer
carrier barrel 38 mate with the drill bit pads 12 on the inner
portions of each cutter pad around the passages 45.
Assuming the cutter pads 12 have been expanded outwardly and the
barrel 38 has been lowered to its final position, as illustrated in
FIGS. 2a, 4a and 16, the drilling fluid will pass downwardly
through the bore 47 of the carrier barrel 38 and then through the
ports 44 provided in the lower portion of the carrier barrel, and
into the passages 45 of the bit pads 12, discharging around the
lower end of the bit pads. Each bit pad has cutting elements 151
mounted in its outer, end, and inner surfaces 130, 131, 132, 133,
which are preferably diamonds set in a suitable matrix of which
each pad 12 is formed. As specifically disclosed, the diamond
cutting elements 151 extend in a desired pattern over the end face
132 of each pad along its inner inclined face 133, over its tapered
drilling face 131, and also over its upper gauge face 130. Suitable
waterways 152 are provided in each pad to insure the flow of
circulating or drilling fluid and the cuttings upwardly around each
pad 12, through the annular space between the wall of the bore hole
and the drive mandrel 10, the drive mandrel barrel 22, and drill
string A, to the drilling rig, the circulating fluid also
maintaining the bit pads and diamond matrix portions in a clean and
cool condition. An additional or alternate fluid course is
illustrated in FIGS. 4a, 12, 13, 16 and 17, by extending the
passages 45 through the bit pads 12 to the guide tracks 117 or
through branching passages 153 below the channels or grooves 155 in
the inner pad surfaces 154 that will permit the drilling fluid to
discharge at the bit face 133.
Assuming the drill string A, drive mandrel barrel 22 and mandrel 10
are disposed in the well bore near its bottom, without the drill
bit mechanism disposed therein, the latter is lowered as a unit on
the wire line 93 from the drilling rig through the drill pipe A and
through the hollow mandrel of a turbine rotor, if a turbine rotor
is used as a source of motive power for rotating the drill
mechanism, with the sets of bit pads 12, links 13, and pad
followers 14 suspended through the cables 15 and rods 16 from the
carrier barrel 38 and arranged in series or tandem fashion. The bit
pads 12 can be of substantial size. There need merely be working
clearance for them to pass through the minimum diameter passage in
the entire drill string A and hollow turbine rotor shaft (if a
turbine is used). If, for example, the minimum diameter through
which the mechanism must pass is 4 inches, then the bit pads 12
need only be slightly less than 4 inches in maximum transverse
dimension, which is also true of the pad follower 14, carrier
barrel 38, and apparatus thereabove. The entire string of mechanism
is lowered on the overshot 92 and electric wire line 93, the
lowermost leading bit pad 12 entering the orienting sleeve 24 and
orienting thereto. Lowering of the entire mechanism on the wire
line continues, the lowermost bar 17 engaging one guide side 101,
102 or the other of the orienting sleeve 24, which will effect a
turning of the carrier barrel 38 and the cutter members suspended
therefrom by means of the rods 16, thereby bringing the pads 12 and
their bars 17 into substantial alignment with the longitudinal
guide grooves 25 in the orienting sleeve 24, which will position
and align fully the lowermost bit pad 12 with the pad deflector or
cone 110 and mandrel slots 11 into which it is to be expanded. If
lowering of the wire line and the entire mechanism continues, the
lowermost bit pad 12 will engage the deflecting cone 110, which
will deflect its lower portion outwardly to engage the guide tracks
117 of the bit pads with the retaining guides 116 of the drive
mandrel 10. Continued lowering will cause the pad follower 14 to
shift outwardly, acting through the link 13 to swing the upper
portion of the lowermost bit pad outwardly until the follower 14 is
also disposed in the slot 11 behind the bit pad.
As lowering of the wire line, latching apparatus and other bit
parts continues, the intermediate or second pad 12 then engages the
cone 110, and such cone will also deflect and guide the next pad
outwardly until its guide portion 117 engages the retaining guides
116 extending into its slot 11, the intermediate follower 14 then
acting through the link 13 to swing the upper portion of the
intermediate pad outwardly within its slot and to place its
follower behind the intermediate pad. As lowering continues, the
third or uppermost bit pad 12 will engage the deflecting cone 110,
which will guide the last pad outwardly to place its guide grooves
117 over the annular strut portion 116 extending into its companion
slot 11, its pad follower 14 then acting through the uppermost link
13 to swing the upper end of the bit pad outwardly, the pad
follower also shifting outwardly within the slot behind the
uppermost pad.
Lowering of the wire line and drill bit mechanism continues, the
lower portion of the carrier barrel 38 moving behind the follower
members 14 and the bit pads 12 until it comes to rest upon the
annular strut 114, as disclosed in FIGS. 4a and 16. The bit pads 12
are now locked in their final position within the slots 11, backed
up by the pad followers or blocking elements 14, the pads 12 being
snugly hooked to the annular strut portions 116 extending into the
mandrel slots 11, and the periphery of the carrier barrel 38
bearing against the pad followers, which, in turn, bear against the
inner surfaces of the pads, the upper ends 128 of the latter being
held snugly against the drive mandrel defining the upper ends 129
of their slots 11. When in this position, the gasket seals 41 at
the lower end of the carrier barrel engage and mate against the bit
pads 12 around its fluid passages 45. When the carrier barrel
arrives in this final position, the latch 65 is then disposed at
the latching groove 75 in the drive barrel 22, the latch expanding
outwardly into such groove and locking the entire mechanism in its
downward position within the drive mandrel barrel 22 and drive
mandrel 10.
As stated above, when the latch snaps into its position within its
groove, as permitted by the absence of tension on the retracting
rod 68, which permits the spring 76 to shift the rod downwardly and
move its retracting pins into the wide portions of the latch slots
73, the telemeter microswitch 94 is actuated by engaging the cap
77, transmitting an appropriate signal through the cable 93 to the
top of the hole or drilling rig that the mechanism has been latched
in its final position. The overshot 92 is then released, in any
suitable manner, from the head 91 of the retracting rod, and the
wire line 93 and overshot 92 pulled up through the drill string A
to the drilling rig. The drilling operation can now commence.
When the drilling mechanism is lowered through the drill string A
toward its position in the drive barrel 22 and mandrel 10, the
lower end of the drive mandrel is preferably several feet off the
bottom of the bore hole. When the drill bit parts have been
expanded outwardly and the drilling mechanism has been latched in
its final position, the wire line 93 and overshot 92 having been
removed, rotation of the drilling apparatus can occur either
through rotating the entire string of drill pipe from the drilling
rig, or through use of the drilling fluid-actuated turbine (not
shown) connected thereto. The drill string A is then lowered until
the drill bit pads 12, as well as the plug bit 18 secured to one of
the pads, engage the bottom of the hole over its entire area.
Appropriate drilling weight is then transmitted from the drill
string through the drive mandrel barrel 22 and drive mandrel 10
directly to the cutters 12, the drilling fluid being pumped through
the drill string and discharging from the lower end of the fluid
passage 47, the ports 44 and passages 45 into the bore hole, to
carry the cuttings upwardly around the drill pads, which, it is to
be noted, are extending laterally outwardly beyond the drive
mandrel 10 to a significant extent, the drive mandrel itself
performing no drilling action upon the formation. The cuttings
produced by the diamond cutting elements 151 are conveyed by the
drilling fluid upwardly around the drill bit apparatus and upwardly
through the annulus around the drill pipe string A toward the
drilling rig, the circulating fluid and cuttings passing upwardly
through the waterways 152 and also around the diamond elements 151
themselves, as well as between the bit pads 12, the diamond cutting
elements and the matrix material in which they are embedded being
maintained in a clean and cool condition, for most effective
penetration of the diamonds into the formation.
To examine the drilling pads, or when the drilling operation is
ended, rotation of the drill bit is stopped and the entire drill
string raised several feet off bottom. The overshot 92 is then
lowered through the drill string on the electric wire line 92 until
it engages over the retracting rod head 91, and upward pull being
taken on the wire line and retracting rod 68 to cause the
retracting pins 72 to engage the cam faces 74 of the latch 65 and
shift the latter inwardly, the retracting rod 68 moving upwardly
and informing the operator at the top of the well bore that the
latch has been retracted through operation of the telemeter
microswitch 94.
As the wire line 93 is moved upwardly, its upward movement is
transmitted through the retracting rod flange 78 to the cap 77 and
to the latch body 43, which is connected through the adapter
coupling 42 to the carrier barrel 38, shifting the carrier barrel
upwardly and elevating it above the bit pads 12 and the pad
followers 14. As the carrier barrel 38 moves upwardly, one of its
shoulders 36 will engage the T-shaped head 35 of the shortest rod
16 and will pull such rod upwardly. Such upward movement is
transmitted through the cable 15 to the follower 14 connected
thereto, the follower being pulled inwardly of the drive mandrel
10, and, through the connecting link 13, swinging the upper portion
of its bit pad 12 inwardly and lifting it and its tracks 117 off
the retaining guides 116 of the drive mandrel 10, pulling the
entire bit pad 12 within the drive mandrel passage 125.
During such upward and inward shifting of the shortest rod 16 and
its attached follower 14, link 13, and bit pad 12, the intermediate
and the longest rod heads 35 have not as yet been engaged by the
shoulders 36 at the lower ends of the carrier barrel grooves 37. It
is only after the bit pad 12 described above has been retracted
fully inwardly within the drive mandrel 10 and elevated above the
location of the other pad followers 14 and bit pads 12 that the
T-shaped head 35 of the intermediate rod 16 will be engaged by its
shoulder 36 at the lower end of the groove 37 in which it lies,
exerting an upward pull on the rod 16 of intermediate length, the
continued elevation of the carrier barrel 38 by the wire line 93
then pulling the intermediate pad follower 14, its link 13, and its
bit pad 12 first inwardly of its slot 11 and then completely within
the drive mandrel passage, the uppermost follower, link and bit pad
shifting upwardly of the drive barrel ahead of the intermediate
parts.
When the intermediate pad 12 has been elevated above the remaining
bit pad and its follower mechanism, the T-shaped head 35 of the
longest rod 16 will be engaged by the carrier barrel shoulder 36 at
the end of its groove 37, which will exert an upward pull on such
rod, which acts through its cable 15 to pull the remaining follower
14 inwardly, and acting through the link 13 to pull the remaining
bit pad 12 inwardly of the mandrel slot 11 into the central passage
of the mandrel 10. The entire mechanism has now been fully
retracted. Elevation of the wire line 93 will remove the entire
drilling mechanism and the entire bit mechanism in tandem array
through the drive barrel 22 and the drill string A to the drilling
rig, where the various bit parts may be inspected and replaced, if
necessary.
After the parts have been examined and replaced, if required, they
are again assembled and related to the drilling mechanism and the
latter appropriately secured to the tandem arrangement of drill bit
mechanism, this combination can again be lowered from the drilling
rig through the drill string A to the drive member 22 and the drive
mandrel 10, the orienting sleeve 24 again appropriately orienting
the several parts so that the bit pads 12 are appropriately
oriented with respect to their mandrel slots 11 and deflector cone
110. The foregoing cycle of operation is repeated to effect the
progressive outward shifting of the bit pads 12, links 13 and
followers 14 within the drive mandrel 10, and the final latching of
the drilling mechanism in position behind the bit pads and
followers, the wire line mechanism being released from the head 91
of the retracting rod 68 and removed from the drill string. The
apparatus is again lowered until the bit pads 12 are bearing
against the bottom of the hole, and the drilling operation can
continue as before.
The operation of running the mechanism on a wire line through the
drill string and shifting the several parts to their final position
is a continuous one. Lowering of the wire line 93 proceeds without
hesitation, with the orienting sleeve 24 and the pad members 17
appropriately turning the carrier barrel 38 and the bit mechanisms
supported thereby in oriented relation into aligned position with
the deflector cone 110 and mandrel slots 11, with the alignment
occurring automatically by virtue of the orienting bars 17 on the
followers 14 engaging the guide surface 101 or 102 of the orienting
sleeve 24. Lowering of the wire line, as stated above, is
continuous until an appropriate signal is given at the drilling rig
advising the operator that the mechanism has been latched in
appropriate position. Similarly, retraction and retrieval of the
mechanism from the drive mandrel 10 and drive barrel 22, and
through the drill string A is a continuous operation. The
engagement of the overshot 92 with the retracting plunger head 91
and partial raising of the rod 68 will provide a signal to the
operator at the top of the well bore, transmitted through the
electric cable, that the latch 65 has been retracted; whereupon,
the wire line is moved upwardly without interruption to elevate the
drill bit mechanism above the bit portions of the apparatus,
followed by successive retraction of the sets of followers 14,
links 13 and bit pads 12 from their positions within the drive
mandrel slots 11, replacing them in tandem array, the elevation of
the wire line continuing, to withdraw the entire mechanism through
the drill pipe A to the drilling rig.
The pad followers 14 are locked in their position behind the pads
12 by the carrier barrel 38. As a result, the horizontal, radial
forces incident to drilling are transmitted from each pad directly
back to the stiff carrier barrel 38, insuring the retention of each
bit pad 12 in its outwardly expanded position. The downward
drilling weight imposed on the bit pads 12 is transmitted directly
from the drive mandrel 10 thereto, relieving the follower and link
mechanisms of such load. The same is true of the drilling torque
which is transmitted directly from the sides of the mandrel slots
11 to the bit pads.
The drill bit disclosed has maximum lateral stability to prevent
drill collar wobble, the drill collars forming the lower portion of
the drilling string A, and which are attached to the drive mandrel
barrel 22 or to a turbine, if a turbine is used to supply the
motive power for rotating the drill bit. Both the vertical gauge
surfaces 130 and the tapered wedging surfaces 131 on the bit pads
provide for such stability. The tapered drilling surfaces 131
permit appropriate sizes, numbers and patterns of diamonds 151 to
be plotted, insuring the presence of appropriate diamonds to
maintain a maximum drilling rate without causing the diamonds to be
locally overloaded, that would result in their failure, and
consequent shortening of the effective life of the drill bit pads
12 and of the drill bit itself, requiring premature retracting and
removal of the parts to the drilling rig for replacement of parts.
It is found that satisfactory diamond coverage is obtained, while
stability is improved to prevent drill collar wobble, by making the
angle of the tapered surfaces 131 of the bit pads about 70.degree.
from the horizontal, and preferably greater than 70.degree.; that
is to say, the tapered surfaces of the bit pads make an angle of
preferably less than 30.degree. with respect to the axis of the
drive mandrel 10. Despite the existence of such relatively steep
taper, it is found that excessive torques are not required to
rotate the bit, the angle of the cone surface 131 being a safe
one.
It is found that the bit pads 12 can be made entirely of matrix
material, with the diamonds 151 molded therewithin. There is no
necessity for providing a steel core and bonding the matrix
material thereto. In the past, the provision of a steel core has
increased the chance of bond failure, since the matrix and the
steel core are of basically dissimilar materials having different
physical properties. The provision of an all matrix and diamond bit
pad increases the strength of the parts and their reliability under
high stress.
The drill bit of the type disclosed enables the bit pads 12 to be
made of relatively large size for the minimum diameter passage
through which they must pass, and yet permits them to drill a bore
hole of a diameter which is more than twice the diameter of the
minimum passage through which the bit cutter members 12 can pass.
By way of example, bit pads 12 capable of passing through a minimum
passage of 4 inches in diameter can be expanded outwardly of the
drive mandrel 10 and locked therewithin to drill a hole of 97/8
inches in diameter, or more than twice the diameter of the minimum
passage through which the parts must pass.
The net result of all of the foregoing is the elimination of slow
round trips with the drilling string A for the purpose of changing
bits, thereby reducing considerably rig time consumed in connection
with bit changes, with attendant major reductions in the cost of
drilling the hole.
* * * * *