U.S. patent number 3,684,041 [Application Number 05/089,606] was granted by the patent office on 1972-08-15 for expansible rotary drill bit.
This patent grant is currently assigned to Baker Oil Tools, Inc.. Invention is credited to Gary R. Johnson, Archer W. Kammerer, Jr..
United States Patent |
3,684,041 |
Kammerer, Jr. , et
al. |
August 15, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
EXPANSIBLE ROTARY DRILL BIT
Abstract
A rotary drill bit having cutters expanded outwardly to drill a
hole substantially greater in diameter than the maximum effective
diameter of the bit with its cutters fully retracted. The cutters
are mounted on expandable and retractable supporting members spaced
circumferentially around the bit, each supporting member having a
cluster of cutters mounted thereon, the cutters in each cluster
being circumferentially or radially spaced from each other, the
cutters collectively cutting upon a formation shoulder in
non-tracking relation. The tool is locked hydraulically with its
cutters in a retracted position, and is unlocked to permit
expansion of the cutters by fluid pressure. Air circulated down the
outside of the tool aerates a liquid column within the tool and in
the drill pipe connected to the tool, causing the greater
hydrostatic head of fluid externally of the bit and drill pipe to
flow across the bottom of the hole toward its axis to flush the
hole bottom of cuttings, clean and cool the cutters, and carry the
cuttings through the tool and drill pipe to a suitable discharge
point above the top of the hole.
Inventors: |
Kammerer, Jr.; Archer W.
(Fullerton, CA), Johnson; Gary R. (Anaheim, CA) |
Assignee: |
Baker Oil Tools, Inc. (City of
Commerce, CA)
|
Family
ID: |
22218582 |
Appl.
No.: |
05/089,606 |
Filed: |
November 16, 1970 |
Current U.S.
Class: |
175/267; 175/286;
175/376 |
Current CPC
Class: |
E21B
10/345 (20130101); E21B 21/12 (20130101); E21B
21/16 (20130101) |
Current International
Class: |
E21B
10/34 (20060101); E21B 21/00 (20060101); E21B
21/12 (20060101); E21B 21/16 (20060101); E21B
10/26 (20060101); F21b 009/26 () |
Field of
Search: |
;175/263-292,391,376 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Leppink; James A.
Claims
We claim:
1. In a rotary drill bit to be lowered in a bore hole: a main body;
means for rotating said body; circumferentially spaced supporting
members mounted on said body for expansion laterally outwardly of
said body and for rotation with said body; a plurality of roller
cutters carried by each supporting member for enlarging the
diameter of the bore hole and thereby produce a transverse shoulder
therein and for operation upon the transverse formation shoulder;
some of the cutters carried by each supporting member being
circumferentially spaced from each other, some of the cutters
carried by each supporting member being laterally spaced from each
other; and means operable while said main body, supporting members
and cutters are being rotated by said rotating means for expanding
said supporting members and cutters carried thereby laterally
outwardly of said body for enlarging the bore hole diameter and for
operation of said cutters upon the transverse formation
shoulder.
2. In a rotary drill bit as defined in claim 1; said cutters
laterally spaced from each other being rotatable about axes lying
in a plane radial of the longitudinal axis of said body.
3. In a rotary drill bit as defined in claim 1; one of said cutters
carried by each supporting member extending laterally outwardly
beyond said supporting member for engagement with the wall of the
bore hole to enlarge the bore hole and cut the transverse shoulder
therein upon lateral outward expansion of said supporting members
and cutters.
4. In a rotary drill bit as defined in claim 1; and detachable
means mounting each roller cutter individually on the lower end of
its supporting member.
5. In a rotary drill bit as defined in claim 1; said cutters
longitudinally spaced from each other being rotatable about axes
lying in a plane radial of the longitudinal axis of said body; one
of said cutters carried by each supporting member extending
laterally outwardly beyond said supporting member for engagement
with the wall of the bore hole to cut the transverse shoulder
therein upon lateral outward expansion of said supporting members
and cutters.
6. In a rotary drill bit as defined in claim 1; said cutters
laterally spaced from each other being rotatable about axes lying
in a plane radial of the longitudinal axis of said body; one of
said cutters carried by each supporting member extending laterally
outwardly beyond said supporting member for engagement with the
wall of the bore hole to enlarge the bore hole and cut the
transverse shoulder therein upon lateral outward expansion of said
supporting members and cutters; and detachable means mounting each
roller cutter individually on the lower end of its supporting
member.
7. In a rotary drill bit as defined in claim 1; a first plurality
of said cutters carried by each supporting member being laterally
spaced from each other and rotatable about axes lying in a first
plane radial of the longitudinal axis of said body; a second
plurality of said cutters carried by each supporting member being
laterally spaced from each other and rotatable about axes lying in
a second plane radial of the longitudinal axis of said body; said
first and second planes being arcuately displaced from each
other.
8. In a rotary drill bit to be lowered in a bore hole: a main body;
circumferentially spaced supporting members mounted on said body
for expansion laterally outwardly of said body; a plurality of
roller cutters carried by each supporting member for operation upon
a transverse formation shoulder in the bore hole; some of the
cutters carried by each supporting member being circumferentially
spaced from each other, some of the cutters carried by each
supporting member being laterally spaced from each other; and means
for expanding said supporting members and cutters carried thereby
laterally outwardly of said body for operation of said cutters upon
the transverse formation shoulder; a first plurality of said
cutters carried by each supporting member being laterally spaced
from each other and rotatable about axes lying in a first plane
radial of the longitudinal axis of said body; a second plurality of
said cutters carried by each supporting member being laterally
spaced from each other and rotatable about axes lying in a second
plane radial of the longitudinal axis of said body; said first and
second planes being arcuately displaced from each other, the
lateral spacing between said first plurality of cutters being
substantially greater than the lateral spacing between said second
plurality of cutters.
9. In a rotary drill bit to be lowered in a bore hole: a main body;
means for rotating said body; circumferentially spaced supporting
members pivotally mounted at their upper portions on said body for
expansion laterally outwardly of said body and for rotation with
said body; each supporting member having a lower mounting base
portion extending transversely in opposite directions substantially
beyond the sides of the portion of the supporting member
thereabove; a plurality of roller cutters for each supporting
member for enlarging the diameter of the bore hole and thereby
produce a transverse shoulder therein and for operation upon the
transverse formation shoulder; a head for each cutter; means
secured to each head rotatably mounting a cutter; and means for
securing each head to the bottom of said base portion with its
roller cutter below said base portion; said heads and cutters being
so carried by said base portion that some of the cutters are
circumferentially spaced from each other, some of the cutters being
laterally spaced from each other; and means operable while said
main body, supporting members and cutters are being rotated by said
rotating means for expanding said supporting members and cutters
laterally outwardly of said body for enlarging the bore hole
diameter and for operation of said cutters upon the transverse
formation shoulder in the bore hole.
10. In a rotary drill bit as defined in claim 9; a first plurality
of said cutters carried by each supporting member being laterally
spaced from each other and rotatable about axes lying in a first
plane radial of the longitudinal axis of said body; a second
plurality of said cutters carried by each supporting member being
laterally spaced from each other and rotatable about axes lying in
a second plane radial of the longitudinal axis of said body; said
first and second planes being arcuately displaced from each
other.
11. In a rotary drill bit to be lowered in a bore hole: a main
body; circumferentially spaced supporting members pivotally mounted
at their upper portions on said body for expansion laterally
outwardly of said body; each supporting member having a lower
mounting base portion extending transversely in opposite directions
substantially beyond the sides of the portion of the supporting
member thereabove; a plurality of roller cutters for each
supporting member; a head for each cutter; means secured to each
head rotatably mounting a cutter; and means for securing each head
to the bottom of said base portion with its roller cutter below
said base portion; said heads and cutters being so carried by said
base portion that some of the cutters are circumferentially spaced
from each other, some of the cutters being laterally spaced from
each other; and means for expanding said supporting members and
cutters laterally outwardly of said body for operation of said
cutters upon a transverse formation shoulder in the bore hole; a
first plurality of said cutters carried by each supporting member
being laterally spaced from each other and rotatable about axes
lying in a first plane radial of the longitudinal axis of said
body; a second plurality of said cutters carried by each supporting
member being laterally spaced from each other and rotatable about
axes lying in a second plane radial of the longitudinal axis of
said body; said first and second planes being arcuately displaced
from each other; the lateral spacing between said first plurality
of cutters being substantially greater than the lateral spacing
between said second plurality of cutters.
12. In a rotary drill bit to be lowered in a bore hole: a main
body; circumferentially spaced supporting members mounted on said
body for expansion laterally outwardly of said body; a plurality of
roller cutters carried by each supporting member for operation upon
a transverse formation shoulder in the bore hole; some of the
cutters carried by each supporting member being circumferentially
spaced from each other, some of the cutters carried by each
supporting member being laterally spaced from each other; a mandrel
connectible to a drill string and slidably splined to said body,
whereby drilling torque is transmitted from said mandrel to said
body; coengageable expander means on said mandrel and supporting
members; and means for relatively shifting said body, supporting
members and roller cutters longitudinally with respect to said
mandrel while said mandrel and body are rotated by the drill string
to cause said expander means to expand said supporting members and
cutters laterally outwardly of said body for some of said cutters
to enlarge the diameter of the bore hole and for said cutters to
operate upon the transverse formation shoulder.
13. In a rotary drill bit as defined in claim 12; a first plurality
of said cutters carried by each supporting member being laterally
spaced from each other and rotatable about axes lying in a first
plane radial of the longitudinal axis of said body; a second
plurality of said cutters carried by each supporting member being
laterally spaced from each other and rotatable about axes lying in
a second plane radial of the longitudinal axis of said body; said
first and second planes being arcuately displaced from each
other.
14. In a rotary drill bit to be lowered in a bore hole: a main
body; circumferentially spaced supporting members mounted on said
body for expansion laterally outwardly of said body; a plurality of
roller cutters carried by each supporting member for operation upon
a transverse formation shoulder in the bore hole; some of the
cutters carried by each supporting member being circumferentially
spaced from each other, some of the cutters carried by each
supporting member being laterally spaced from each other; a mandrel
connectible to a drill string and slidably splined to said body,
whereby drilling torque is transmitted from said mandrel to said
body; coengageable expander means on said mandrel and supporting
members; and means for relatively shifting said body, supporting
members and roller cutters longitudinally with respect to said
mandrel to cause said expander means to expand said supporting
members and cutters laterally outwardly of said body for operation
of said cutters upon the transverse formation shoulder; a first
plurality of said cutters carried by each supporting member being
laterally spaced from each other and rotatable about axes lying in
a first plane radial of the longitudinal axis of said body; a
second plurality of said cutters carried by each supporting member
being laterally spaced from each other and rotatable about axes
lying in a second plane radial of the longitudinal axis of said
body; said first and second planes being arcuately displaced from
each other; the lateral spacing between said first plurality of
cutters being substantially greater than the lateral spacing
between said second plurality of cutters.
15. In a rotary drill bit to be lowered in a bore hole: a main
body; circumferentially spaced supporting members pivotally mounted
at their upper portions on said body for expansion laterally
outwardly of said body; each supporting member having a lower
mounting base portion extending circumferentially in opposite
directions substantially beyond the sides of the portion of the
supporting member thereabove; a plurality of roller cutters for
each supporting member; a head for each cutter; means secured to
each head rotatably mounting a cutter; means for securing each head
to the bottom of said base portion with its roller cutter below
said base portion; said heads and cutters being so carried by said
base portion that some of the cutters are circumferentially spaced
from each other, some of the cutters being laterally spaced from
each other; a mandrel connectible to a drill string and slidably
splined to said body, whereby drilling torque is transmitted from
said mandrel to said body; coengageable expander means on said
mandrel and supporting member; and means for relatively shifting
said body, supporting members and roller cutters longitudinally
with respect to said mandrel while said mandrel and body are
rotated by the drill string to cause said expander means to expand
said supporting members and cutters laterally outwardly of said
body for some of said cutters to enlarge the diameter of the bore
hole and for said cutters to operate upon a transverse formation
shoulder in the bore hole.
16. In a rotary drill bit as defined in claim 15; a first plurality
of said cutters carried by each supporting member being laterally
spaced from each other and rotatable about axes lying in a first
plane radial of the longitudinal axis of said body; a second
plurality of said cutters carried by each supporting member being
laterally spaced from each other and rotatable about axes lying in
a second plane radial of the longitudinal axis of said body; said
first and second planes being arcuately displaced from each
other.
17. In a rotary drill bit to be lowered in a bore hole: a main
body; circumferentially spaced supporting members pivotally mounted
at their upper portions on said body for expansion laterally
outwardly of said body; each supporting member having a lower
mounting base portion extending circumferentially in opposite
directions substantially beyond the sides of the portion of the
supporting member thereabove; a plurality of roller cutters for
each supporting member; a head for each cutter; means secured to
each head rotatably mounting a cutter; means for securing each head
to the bottom of said base portion with its roller cutter below
said base portion; said heads and cutters being so carried by said
base portion that some of the cutters are circumferentially spaced
from each other, some of the cutters being laterally spaced from
each other; a mandrel connectible to a drill string and slidably
splined to said body, whereby drilling torque is transmitted from
said mandrel to said body; coengageable expander means on said
mandrel and supporting member; and means for relatively shifting
said body, supporting members and roller cutters longitudinally
with respect to said mandrel to cause said expander means to expand
said supporting members and cutters laterally outwardly of said
body for operation of said cutters upon a transverse formation
shoulder in the bore hole; a first plurality of said cutters
carried by each supporting member being laterally spaced from each
other and rotatable about axes lying in a first plane radial of the
longitudinal axis of said body; a second plurality of said cutters
carried by each supporting member being laterally spaced from each
other and rotatable about axes lying in a second plane radial of
the longitudinal axis of said body; said first and second planes
being arcuately displaced from each other; the lateral spacing
between said first plurality of cutters being substantially greater
than the lateral spacing between said second plurality of
cutters.
18. In a rotary drill bit to be lowered in a bore hole: a main
body; circumferentially spaced supporting members mounted on said
body for expansion laterally outwardly of said body; a plurality of
roller cutters carried by each supporting member for operation upon
a transverse shoulder in the bore hole; some of the cutters carried
by each supporting member being circumferentially spaced from each
other, some of the cutters carried by each supporting member being
laterally spaced from each other; a mandrel connectible to a drill
string and slidably splined to said body, whereby drilling torque
is transmitted from said mandrel to said body; coengageable
expander means on said mandrel and supporting members; said body
having a cylinder portion above said expander means slidably and
sealingly engaging said mandrel; said mandrel having a piston
portion in said cylinder portion slidably and sealingly engaging
said cylinder portion and dividing said cylinder portion into upper
and lower fluid pressure chambers; and means for feeding fluid
under pressure into one of said chambers to relatively shift said
body, supporting members and roller cutters longitudinally with
respect to said mandrel while said mandrel and body are rotated by
the drill string to cause said expander means to expand said
supporting members and cutters laterally outwardly of said body for
some of said cutters to enlarge the diameter of the bore hole and
for said cutters to operate upon the transverse formation
shoulder.
19. In a rotary drill bit as defined in claim 18; said fluid
feeding means comprising a conduit externally of said mandrel
communicating with said one of said chambers.
20. In a rotary drill bit to be lowered in a bore hole: a main
body; circumferentially spaced supporting members mounted on said
body for expansion laterally outwardly of said body; a plurality of
roller cutters carried by each supporting member for operation upon
a transverse shoulder in the bore hole; some of the cutters carried
by each supporting member being circumferentially spaced from each
other, some of the cutters carried by each supporting member being
laterally spaced from each other; a mandrel connectible to a drill
string and slidably splined to said body, whereby drilling torque
is transmitted from said mandrel to said body; coengageable
expander means on said mandrel and supporting members; said body
having a cylinder portion above said expander means slidably and
sealingly engaging said mandrel; said mandrel having a piston
portion in said cylinder portion slidably and sealingly engaging
said cylinder portion and dividing said cylinder portion into upper
and lower fluid pressure chambers; and means for feeding fluid
under pressure into one of said chambers to relatively shift said
body, supporting members and roller cutters longitudinally with
respect to said mandrel to cause said expander means to expand said
supporting members and cutters laterally outwardly of said body for
operation of said cutters upon the transverse formation shoulder; a
liquid confined in said other of said chambers initially preventing
such relative longitudinal shifting; and means for releasing said
liquid from said other of said chambers while the drill bit is in
the bore hole.
21. In a rotary drill bit to be lowered in a bore hole: a main
body; circumferentially spaced supporting members mounted on said
body for expansion laterally outwardly of said body; a plurality of
roller cutters carried by each supporting member for operation upon
a transverse shoulder in the bore hole; some of the cutters carried
by each supporting member being circumferentially spaced from each
other, some of the cutters carried by each supporting member being
laterally spaced from each other; a mandrel connectible to a drill
string and slidably splined to said body, whereby drilling torque
is transmitted from said mandrel to said body; coengageable
expander means on said mandrel and supporting members; said body
having a cylinder portion above said expander means slidably and
sealingly engaging said mandrel; said mandrel having a piston
portion in said cylinder portion slidably and sealingly engaging
said cylinder portion and dividing said cylinder portion into upper
and lower fluid pressure chambers; and means for feeding fluid
under pressure into one of said chambers to relatively shift said
body, supporting members and roller cutters longitudinally with
respect to said mandrel to cause said expander means to expand said
supporting members and cutters laterally outwardly of said body for
operation of said cutters upon the transverse formation shoulder;
said one of said chambers being said upper chamber whereby fluid
under pressure fed thereinto elevates said body, supporting members
and cutters along said mandrel.
22. In a rotary drill bit as defined in claim 21; a liquid confined
in said lower chamber initially preventing elevation of said body,
supporting members and cutters along said mandrel; and means for
releasing said liquid from said lower chamber while the drill bit
is in the bore hole.
23. In a rotary drill bit as defined in claim 21; a liquid confined
in said lower chamber initially preventing elevation of said body,
supporting members and cutters along said mandrel; and means for
releasing said liquid from said lower chamber while the drill bit
is in the bore hole; said fluid feeding means comprising a conduit
externally of said mandrel communicating with said upper
chamber.
24. In a rotary drill bit as defined in claim 21; a liquid confined
in said lower chamber initially preventing elevation of said body,
supporting members and cutters along said mandrel; and means for
releasing said liquid from said lower chamber while the drill bit
is in the bore hole; said fluid feeding means comprising a conduit
externally of said mandrel communicating with said upper chamber;
and means for feeding compressed air into said mandrel to aerate
the liquid column therein and in the drill string thereabove,
whereby liquid in the well bore externally of the drill bit flushes
cuttings into the mandrel for upward passage through the mandrel
and drill string.
25. In a rotary drill bit to be lowered in a bore hole: a main
body; circumferentially spaced supporting members mounted on said
body for expansion laterally outwardly of said body; a plurality of
roller cutters carried by each supporting member for operation upon
a transverse formation shoulder in the bore hole; some of the
cutters carried by each supporting member being circumferentially
spaced from each other, some of the cutters carried by each
supporting member being laterally spaced from each other; a mandrel
connectible to a drill string and slidably splined to said body,
whereby drilling torque is transmitted from said mandrel to said
body; coengageable expander means on said mandrel and supporting
members; and means for relatively shifting said body, supporting
members and roller cutters longitudinally with respect to said
mandrel to cause said expander means to expand said supporting
members and cutters laterally outwardly of said body for operation
of said cutters upon the transverse formation shoulder; and means
for feeding compressed air into said mandrel to aerate the liquid
column therein and in the drill string thereabove, whereby liquid
in the well bore externally of the drill bit flushes cuttings into
the mandrel for upward passage through the mandrel and drill
string.
26. In a rotary drill bit to be lowered in a bore hole: a main
body; cutter means mounted on said body for expansion laterally
outwardly of said body; a mandrel connectible to a drill string and
slidably splined to said body, whereby drilling torque is
transmitted from said mandrel to said body; coengageable expander
means on said mandrel and cutter means; said body having a cylinder
portion above said expander means slidably and sealingly engaging
said mandrel; said mandrel having a piston portion in said cylinder
portion slidably and sealingly engaging said cylinder portion and
dividing said cylinder portion into upper and lower fluid pressure
chambers; means for feeding fluid under pressure into one of said
chambers to relatively shift said body and cutter means
longitudinally with respect to said mandrel to cause said expander
means to expand said cutter means laterally outwardly of said body;
a liquid confined in said other of said chambers initially
preventing such relative longitudinal shifting; and means for
releasing said liquid from said other of said chambers while the
drill bit is in the bore hole.
27. In a rotary drill bit as defined in claim 26; said one of said
chambers being said upper chamber, whereby fluid under pressure fed
thereinto elevates said body and cutter means along said mandrel;
said other of said chamber being said lower chamber in which the
liquid is confined.
28. In a rotary drill bit as defined in claim 26; said one of said
chambers being said upper chamber, whereby fluid under pressure fed
thereinto elevates said body and cutter means along said mandrel;
said other of said chamber being said lower chamber in which the
liquid is confined; said fluid feeding means comprising a conduit
externally of said mandrel communicating with said upper
chamber.
29. In a rotary drill bit as defined in claim 26; said one of said
chambers being said upper chamber, whereby fluid under pressure fed
thereinto elevates said body and cutter means along said mandrel;
said other of said chamber being said lower chamber in which the
liquid is confined; said fluid feeding means comprising a conduit
externally of said mandrel communicating with said upper chamber;
and means for feeding compressed air into said mandrel to aerate
the liquid column therein and in the drill string thereabove,
whereby liquid in the well bore externally of the drill bit flushes
cuttings into the mandrel for upward passage through the mandrel
and drill string.
Description
The present invention relates to rotary drill bits, and more
particularly to rotary drill bits having expansible cutters for
enlarging the diameters of bore holes.
Rotary drill bits having expansible cutters are used for passing
through a bore hole casing, or into an open bore hole of a
particular diameter, and of substantially enlarging the bore hole
to another desired diameter. Difficulties have heretofore been
encountered in providing expansible drill bits which are capable of
enlarging holes of relatively large diameter to still substantially
greater diameters. A multiplicity of rotary cutters has been used
for performing a drilling action upon a transverse formation
shoulder, or annular step, between the wall of the original hole
and the wall of the enlarged hole, each cutter being mounted upon
an individual supporting arm or member pivotally carried by the
main body of the bit for outward movement from retracted to
expanded positions to correspondingly shift the cutter carried
thereby outwardly. The number of cutters and supporting arms or
members could be reduced through use of larger diameter cutters.
However, there is an optimum size that can be used, which, for
example, may be about 10 to 11 inches in diameter, cutters larger
than such size becoming inefficient and, therefore, uneconomical.
Because of the many cutters required to effectively cover the
formation shoulder of relatively large area and radial extent, a
correspondingly great multiplicity of cutter supporting members
were required, which limited the number of arms and cutters that
could be carried by the body structure for movement between
retracted and expanded positions so that the cutters would be
operable on the same formation shoulder. This limitation
necessitated the provision of sets of arms and cutters
longitudinally spaced from each other, the sets of cutters being
expanded outwardly to progressively increased extents in upward
sequence to enlarge the bore hole in stages or steps to the
required final diameter. Accordingly, the prior expansible rotary
drill bits were of extended length, possessed of a large number of
parts, and comparatively complex and costly.
By virtue of the present invention, a rotary drill bit of the
expansible type is provided, which is capable of enlarging a
comparatively large diameter hole, for example, about 5 feet in
diameter, to a substantially greater diameter, for example, about 8
feet, a relatively small number of cutter supporting members being
used, all disposed in substantially the same transverse plane of
operation, each supporting member carrying a multiplicity or
cluster of cutters for collective operation upon substantially the
entire area of the formation shoulder. The clustered cutters are
preferably mounted in such manner as to be in non-tracking relation
with respect to each other upon the formation shoulder. The rotary
drill bit provided is of much shorter length than prior devices,
embodying fewer parts. It is easier to assemble and dismantle and
is more economical to manufacture. Each cutter and each cluster of
cutters is replaceable, when worn, in a relatively simple and
expeditious manner.
The supporting members and cutters of the expansible rotary drill
bit are prevented from being expanded outwardly of the main body of
the bit by a hydraulic lock, which is released when desired.
Expansion of the supporting members and cutters occurs through use
of compressed air, or other gaseous medium, as a motivating fluid,
the compressed air also being used for effecting elevation of the
cuttings produced by the cutters through the tool and drill pipe
connected thereto to a desired disposal area.
This invention possesses many other advantages, and has other
purposes 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:
FIG. 1 is a side elevational view, parts being shown in section, of
a rotary drill bit embodying the invention disposed in a subaqueous
bore hole, the cutters and the supporting members in which they are
mounted being disposed in retracted position;
FIG. 2 is a partial longitudinal section, on an enlarged scale,
through the drill bit illustrated in FIG. 1;
FIG. 3 is an enlarged section taken along the line 3--3 on FIG.
1;
FIG. 4 is an enlarged section taken along the line 4--4 on FIG.
1;
FIG. 5 is a side elevational view of the drill bit, with its cutter
supporting members and cutters in expanded position for enlarging
the diameter of the bore hole;
FIG. 6 is an enlarged fragmentary section of a portion of the
apparatus disclosed in FIG. 5;
FIG. 7 is a cross-section taken along the line 7--7 on FIG. 5;
FIG. 8 is an enlarged bottom plan view of a cluster of cutters
mounted on the lower end of a supporting member.
A rotary expansible drill bit A is secured to the lower end of a
rotary drill pipe string B extending upwardly to a drilling rig
(not shown). As specifically illustrated, the drill bit is lowered
through a bore hole C drilled downwardly from an ocean or sea floor
D, the drill bit being of the expansible type so as to enlarge the
diameter of the bore hole C. The rotary drill bit is particularly
designed for enlarging bore holes of relatively large
diameters.
The upper portion of the rotary drill bit consists of a tubular
mandrel 10 that includes an upper kelly section 11 provided with an
external flange 13 suitably bolted to a companion flange 14 at the
lower end of a tubular adapter structure 15, the upper end of this
structure having a flange 16 adapted to be bolted, or otherwise
suitably secured, to the lower end 17 of the rotary drill pipe
string B that extends upwardly through the water to the drilling
rig used for rotating the apparatus and for imposing appropriate
drilling weight thereon. The lower portion 18 of the kelly or upper
mandrel section 11 is slidably splined to a body structure 19 of
the drill bit, by making such lower portion of the kelly
non-circular in external shape, which fits within a companion
non-circular bore 20 of a companion section 21 of the body
structure, the mandrel 10 and body structure 19 being
longitudinally shiftable with respect to each other, with rotary
motion and torque being transmittable from the kelly to the body
structure.
The body structure includes an upper cylinder portion 22 that has a
lower cylinder head 23 at the upper end of the torque drive section
21 of the body structure, and into which the kelly 11 is slidably
splined. The lower head 23 of the cylinder is secured to a cylinder
skirt 24 in any suitable manner, as by means of screws 25, a gasket
between the lower end of the sleeve and head preventing leakage
therebetween. The upper end of the cylinder sleeve is suitably
secured, as by the use of welding material 26, to an upper head 27
that extends inwardly to the cylindrical portion 28 of the kelly
section. Leakage of fluid between the upper head and kelly is
prevented by a suitable side seal ring 29 in the upper head
slidably and sealingly engaging the kelly periphery 28. Similarly,
leakage of fluid between the lower head 23 and cylindrical
perimeter 28 of the kelly is prevented by one or more side seal
rings 30 in the head slidably and sealingly engaging against the
kelly.
The sleeve 24 is laterally spaced from the periphery 28 of the
kelly to define an annular cylinder space 31 therebetween, which is
divided by a piston 32 secured to the kelly into an upper pressure
expander chamber 33 and a lower lock chamber 34. The piston is
secured to the kelly by longitudinally spaced snap rings 35
disposed in kelly grooves 36 and engaging upwardly facing and
downwardly facing surfaces of the piston 32, fluid leakage between
the piston and kelly being prevented by a suitable side seal ring
37 in the kelly engaging the inner periphery of the piston.
Similarly, leakage of fluid between the exterior of the piston and
the cylinder sleeve 24 is prevented by a suitable piston or seal
ring 38 on the piston slidably and sealingly engaging the inner
wall of the cylinder skirt.
The mandrel 10 includes a lower section 39, which is swivelly
connected to the kelly section 11 thereabove by means of a split
ring 40 received within a peripheral groove 41 in the lower mandrel
section and which underlies and engages a downwardly facing kelly
shoulder 42. A split ring 43 is received within an inner
circumferential groove 44 in the kelly which underlies the other
ring 40, the kelly ring being retained in its groove and in
underlying relation to the other ring by a sleeve 45 encircling the
lower member 39 and disposed behind the kelly ring 43, downward
movement of this sleeve being prevented by one or a plurality of
screws 46 threaded into the lower mandrel section 39 and underlying
the retainer ring 45. The lower mandrel section 39 extends into a
cutter supporting body section 47 which is suitably secured, as by
means of bolts or screws 48, to the torque drive body section 21,
the lower end of the lower mandrel section being telescopically
arranged within a lower body section 49 suitably secured to the
cutter supporting section 47 by one or a plurality of bolts or
screws 50. This lower section has a bottom flange 51 to which the
upper flange 52 of a suitable rotary drill bit E can be secured by
bolts 53, or the like, the lower body section having a central
passage 54 therethrough communicating with a central passage 55 in
the lower drill bit which opens into the bore hole C therebelow.
The body of the lower drill bit E has a plurality of cutters 56
thereon to cover the entire bottom area of the bore hole to drill
the same. The disposition of the cutters 56 on the lower drill bit
forms no part of the present invention, and for that reason is not
illustrated. A very large number of the cutters 56 secured to the
body of the lower drill bit are not illustrated in the interest of
clarity. It is sufficient to note that the lower drill bit will
drill the bore hole C to an initial diameter, such as illustrated
in FIG. 1 of the drawings.
The body structure has a plurality of expansible parts mounted on
it, including cutter supporting members 57 spaced circumferentially
around the body structure, each cutter supporting member being
pivotally mounted in a body slot 58 on a hinge pin 59 secured to
the cutter mounting body section 47. As shown, the sides of each
slot are provided by vertically disposed parallel side plates 60
welded, or otherwise suitably secured, to the upper and lower
flanges of the body section 47, the cutter supporting member or arm
57 being slidable along such side plates so that torque can be
transmitted from the body structure 19 to the cutter supporting
member. Each supporting member or arm has stop elements 61 secured
to its sides that are engageable with companion stop elements 62 on
the vertical side plates, to limit the maximum extent of outward
expansion of the supporting members.
Each cutter supporting member 57 terminates at its lower end in a
mounting base 63 extending transversely beyond the sides of the
supporting member thereabove. Secured to each mounting base, as by
means of threaded studs 64, or the like, are a plurality of
mounting heads 65 from which arms 66 depend having bearing
supporting pins 67 extending inwardly thereof, on each of which a
roller cutter 68a, 68b, 68c or 68d is rotatably mounted, in a known
manner. As disclosed, a cluster of cutters 68a, 68b, 68c, 68d is
carried by each supporting member 57, the cutters being
individually rotatably about their supporting bearings 67, some of
the cutters 68a, 68b and 68c, 68d being radially spaced from each
other, some cutters, such as 68a, 68c and 68b, 68d also being
circumferentially spaced from one another. The arrangement is such
that a relatively large number of cutters can be carried by each
supporting arm, and yet the supporting arms 57 and their cutters
can be substantially fully nested within the confines of the body
structure 19 when in a retracted position. When expanded outwardly,
the sets of cutters will collectively operate upon the entire
annular formation shoulder S that will be produced in the bore hole
as a result of outward expansion and rotation of the supporting
members and cutters, the cutters in each set being differently
arranged on each supporting arm so that the cutters do not track
one another upon the formation shoulder. As shown, the cutters 68a,
68b of each set rotate about axes lying in a radial plane through
the bit axis angularly displaced with respect to the radial plane
in which the rotational axes of the cutters 68c, 68d lie. Moreover,
the radial spacing between the cutters 68a, 68b is substantially
smaller than the radial spacing between the cutters 68c, 68 d. The
cutters extend different radial distances from the bit axis to
assure coverage of the full shoulder S by the cutters. With a
minimum number of supporting members and by virtue of the use of a
cluster of cutters carried by each supporting member, a large
increase in bore hole diameter can be secured with respect to a
large diameter initial bore hole C using a limited number of cutter
supporting members 57, which all operate substantially in
substantially the same plane.
The cutter supporting members 57 and cutter 68a-68d carried thereby
tend to occupy a retracted position substantially entirely within
the confines of the body structure 19 of the expansible bit. These
cutter supporting members and cutters are expandable outwardly to
enlarge the diameter of the well bore H and to operate upon the
formation shoulder S that the cutters produce in the latter as a
result of their outward expansion. To accomplish the expansion,
each cutter supporting member 57 has an inclined expander surface
70 on its inner portion below the hinge pin 59 which tapers in a
downward and inward direction. Each expander surface terminates in
a lock surface 71 formed on the cutter supporting member. The
outward expansion is accomplished by producing relative
longitudinal movement between the mandrel 10 and the body structure
19, which will produce corresponding relative longitudinal movement
between the cutter supporting members 57 and lock and expander
sections 72 formed on the lower mandrel section 39 projecting
outwardly into the mandrel slots 58. The lock and expander portions
are adapted to engage the expander surfaces 70 and the lock
surfaces 71. Upon relative downward movement of the lock and
expander portions 72 along the cutter supporting members, they
engage and slide downwardly along the expander surfaces 70,
shifting the supporting members 57 and cutters 68-68d outwardly
while the expansible rotary drill bit A is being rotated by the
string of drill pipe B, the outermost cutters 68a digging into the
formation wall to effect an enlargement of the hole diameter.
Outward expansion continues until the lower end 11a of the kelly 11
bottoms against a wear plate 75 clamped between the lower and upper
ends of the torque and cutter mounting body sections 21, 47, at
which time lock surfaces 76 on the members 72 will be disposed
behind their companion lock surfaces 71 on the supporting members
57, further outward expansion of the supporting members being
prevented by engagement of their stop shoulders 61 with companion
shoulders 62 on the vertical plates 60 of the body section 47.
Relative longitudinal movement between the mandrel 10 and body
structure 19 is initially prevented by disposing the mandrel in its
uppermost position with respect to the body structure, the piston
32 engaging the upper cylinder head 27, and the lock chamber 34
being filled with sea water, or other liquid, retained therein, but
which can be permitted to bleed therefrom by opening a suitable
valve 80 secured to the lower head and which communicates with the
lock chamber. Assuming that the liquid in the lock chamber 34 has
been permitted to bleed therefrom, a suitable fluid medium, such as
compressed air, or other compressed gas, is forced through a
compressed air line 81 extending downwardly from the drilling rig
and along the drill pipe B, this air line communicating with a pipe
82 connected to the upper head 27 and which communicates with the
pressure expansion chamber 33. Air under pressure will enter the
expansion chamber, acting upon the upper cylinder head 27 and
elevating the body structure 19 along the mandrel 10 while the
drill pipe B and body structure are rotated, the rotation of the
body structure being transferred through the plates 60 to the
cutter supporting members 57 to rotate the latter and their cutters
68a-68d in the bore hole, to effect cutter expansion and the
production of the formation shoulder S, as described above. Once
the cutter supporting members and cutters have been expanded
outwardly to their maximum extent, drilling weight is transmitted
through the string of drill pipe B to the mandrel 10, from the
lower end 11a of the mandrel kelly to the body structure, this
drilling weight passing through the stop shoulders 62, 61 to the
cutter supporting members 57 and cutters 68a-68d which are bearing
upon the formation shoulder S while the apparatus is being rotated
by the drill string.
The cuttings produced by the cutters are circulated from the bore
hole by compressed air pumped down the same line 81 that conducts
air to the pressure chamber 33, as well as through one or more
other compressed air lines 81a extending downwardly along the drill
pipe. Thus, a compressed air line 83 extends from the branch 82
leading to the pressure chamber, this line extending downwardly
along the body structure and communicating with a radial air inlet
port 84 in the lower body section below the expansible cutters, the
air discharging therefrom through orifices 85 into the central
passage 54 in the lower body section 49, which communicates with
the tubular mandrel 10 and the rotary drill pipe B thereabove.
Similarly, the other compressed air line 81a extends downwardly
along the apparatus and communicates with an air inlet port 84 that
opens through orifices 85 into the central passage 54. The pumping
of air through the lines into the central passage will aerate or
lighten the liquid column in the central passage through the
apparatus A and in the rotary drill pipe string B, causing the
water in the well bore, such as the ocean water, surrounding the
apparatus and the drill pipe to flow downwardly around the exterior
of the apparatus to the lower drill bit E, and then upwardly
through the central passages 55, 54, flushing the cuttings in the
bore hole produced by the expandable cutters 68a-68d toward the
axis of the apparatus, and then conveying them upwardly at a
substantial velocity through the central passages 55, 54, mandrel
10 and the string of drill pipe B to the drilling rig for suitable
disposal.
The bleeder valve 80 is disclosed only diagrammatically since its
specific details from no part of the present invention. It is
sufficient to state that such valve is remotely controlled from the
drilling rig, being closed when the cutters and supporting members
57 are in retracted position with the lock chamber 34 filled with
sea water or other liquid. All of the compressed air pumped down
through the air lines 81, 81a discharge into the central passage 54
to aerate and thus lighten the fluid column in the bit A, as well
as in the drill pipe B, so that the cuttings in the well bore can
be flushed upwardly through the bit and drill pipe.
With the apparatus disclosed, the expansible drill bit portion A is
retained locked in its retracted condition and the initial diameter
of bore hole C can be drilled commencing from the ocean floor D by
the lower drill bit E, while compressed air is being pumped down
through the lines 81, 81a, the cuttings being carried upwardly
through the central passages 55, 54, mandrel 10 and drill pipe B.
When the hole has been drilled to the desired depth, the apparatus
can be elevated to a location at which enlargement of the bore hole
is to commence, whereupon the bleeder valve 80 is opened to allow
discharge of the locking liquid from the lock chamber 34,
compressed air entering the upper pressure chamber 33 to elevate
the body structure 19 with respect to the mandrel 10 while the
rotary drill string B and body structure are rotated, the expander
surfaces 70 on the cutter supporting members 57 engaging the lock
and expander 72 and being gradually expanded outwardly while the
rotation of the apparatus continues, so that the cutters 68a
enlarge the hole to a greater diameter H, the extent of enlargement
being determined by engagement of the stop shoulders 61 on the
supporting members with the companion stop shoulder 62 of the body
structure, at which time the lock portions 76 of the lock and
expander members are disposed behind the lock surfaces 71 to
prevent the supporting members and cutters from being moved
inwardly. When the well bore H has been enlarged to the required
diameter, as determined by the extent of outward expansion of the
supporting members and cutters, downward drilling weight is imposed
on the drill pipe B and mandrel 10 which is transmitted to the body
structure 19, cutter supporting members 57 and cutters 68a, 68d,
the drill pipe being rotated to rotate the apparatus. At the same
time, compressed air is flowing through the lines 81, 81a, 83 and
discharging into the central passage 54, aerating the liquid column
therein and in the drill pipe so that the sea water flushes the
cuttings produced to the lower end of the passage 55 and upwardly
therethrough for conveyance to the drilling rig, or other suitable
location above the ocean floor. The hole enlarging operation
continues until the well bore H has been enlarged downwardly to the
desired longitudinal extent.
The apparatus can now be retracted by ceasing pumping of air
through the line 81 and elevating the string of drill pipe B, which
will pull the mandrel 10 upwardly to dispose the lock and expander
elements 72 above the expander surfaces 70, these lock elements
engaging fingers 90 on the supporting members 57 extending inwardly
from the pivot pins 59, so as to swing such fingers inwardly and
the supporting arms and cutters below the hinge pins inwardly to
their fully retracted position. The apparatus can now be elevated
and removed from the bore hole.
In the event that any of the cutters 68a-68 d becomes worn, such
cutter is readily replaced by removing the head 65 from the
mounting base 63 of the supporting arm through removal of the studs
64, a new cutter and head assembly being substituted in its place
and secured to the mounting base.
In the event that the initial bore hole C has previously been
drilled, the lower drill bit E need not be used at all, the
apparatus A being lowered by the drill pipe B into the bore hole to
the location at which the hole enlarging operation is to commence,
after which the supporting members 57 and cutters 68a-68d are
expanded outwardly and the hole enlarged to the desired extent, in
the manner described above, the supporting members and cutters
being retracted by picking up on the mandrel 10, the lock and
expanders 72 engaging the fingers 90 to swing the supporting
members and cutters inwardly.
* * * * *