U.S. patent number 3,709,308 [Application Number 05/094,399] was granted by the patent office on 1973-01-09 for diamond drill bits.
This patent grant is currently assigned to Christensen Diamond Products Company. Invention is credited to David S. Rowley, Charles E. Ward.
United States Patent |
3,709,308 |
Rowley , et al. |
January 9, 1973 |
DIAMOND DRILL BITS
Abstract
Diamond drill bits for drilling oil, gas, water, mining, and
similar, bore holes in formations, in which cube diamonds are set
in the drilling face of a bit with the diamonds arranged in
generally radial rows and with the leading or cutting faces of the
diamonds also arranged generally radially to enhance cutting of
certain formations, such as relatively soft or evaporite
formations. The leading faces of the rows of diamonds form the
trailing sides of fluid waterways or channels through which
drilling fluid flows. In some forms of bits, conventional generally
round rows of diamonds are used in conjunction with the cube
diamonds to limit the depth of penetration of the cube diamonds
into the formation.
Inventors: |
Rowley; David S. (Salt Lake
City, UT), Ward; Charles E. (Salt Lake City, UT) |
Assignee: |
Christensen Diamond Products
Company (Salt Lake City, UT)
|
Family
ID: |
22244941 |
Appl.
No.: |
05/094,399 |
Filed: |
December 2, 1970 |
Current U.S.
Class: |
175/434 |
Current CPC
Class: |
E21B
10/46 (20130101) |
Current International
Class: |
E21B
10/46 (20060101); E21b 009/36 () |
Field of
Search: |
;175/329,330,410,327 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Brown; David H.
Claims
We claim:
1. In a rotary bit: a body having a cutting face for drilling a
hole; circumferentially spaced generally radial rows of polyhedron
diamond cutting elements in said face, the cutting elements in each
row having exposed leading substantially flat faces and lower
cutting edges both disposed in a generally radial plane extending
from the rotational axis of the bit.
2. In a rotary bit as defined in claim 1; said cutting elements
being of cube form.
3. In a rotary bit as defined in claim 1; the substantially flat
face of said cutting elements being disposed in said cutting face
with a negative rake.
4. In a rotary bit as defined in claim 1; said cutting elements
being diamonds of cube form; the substantially flat faces of said
cutting elements being disposed in said cutting face with a
negative rake.
5. In a rotary bit: a body having a cutting face for drilling a
hole; circumferentially spaced generally radial rows of polyhedron
cutting elements in said face, the cutting elements in each row
having leading faces and lower cutting edges disposed in a
generally radial plane extending from the rotational axis of the
bit; and circumferentially spaced generally radial rows of
generally round cutting elements in said cutting face interposed
between said rows of polyhedron cutting elements.
6. In a rotary bit as defined in claim 5; said polyhedron cutting
elements being diamonds of cube form; said generally round cutting
elements being diamonds.
7. In a rotary bit as defined in claim 5; said polyhedron cutting
elements being diamonds of cube form; said generally round cutting
elements being diamonds; said diamonds of cube form being disposed
in said cutting face with a negative rake.
8. In a rotary bit adapted to be lowered in a hole on a tubular
drill string: a body having a cutting face for drilling a hole and
passage means for receiving fluid from the drill string; said face
having generally radial waterways communicating with said passage
means and extending to the outer portion of the face and providing
a plurality of lands therebetween extending laterally from an inner
portion of the face to the outer portion of the face;
circumferentially spaced generally radial rows of polyhedron
cutting elements in a plurality of said lands adjacent to at least
some of said waterways, the cutting elements in each row having
exposed leading substantially flat faces and lower cutting edges
both disposed in a generally radial plane extending from the
rotational axis of the body, said exposed leading faces in each row
forming at least a portion of the trailing side of an adjacent
waterway.
9. In a rotary bit as defined in claim 8; said cutting elements
being of cube form.
10. In a rotary bit as defined in claim 8; the substantially flat
face of said cutting elements being disposed in said cutting face
with a negative rake.
11. In a rotary bit as defined in claim 8; said cutting elements
being diamonds.
12. In a rotary bit as defined in claim 8; said cutting elements
being diamonds of cube form.
13. In a rotary bit as defined in claim 8; said cutting elements
being diamonds of cube form; the substantially flat faces of said
cutting elements being disposed in said cutting face with a
negative rake.
14. In a rotary bit adapted to be lowered in a hole on a tubular
drill string: a body having a cutting face for drilling a hole and
passage means for receiving fluid from the drill string; said face
having generally radial waterways communicating with said passage
means and extending to the outer portion of the face and providing
a plurality of lands therebetween extending laterally from an inner
portion of the face to the outer portion of the face;
circumferentially spaced generally radial rows of polyhedron
cutting elements in a plurality of said lands adjacent to at least
some of said waterways, the cutting elements in each row having
leading faces and lower cutting edges disposed in a generally
radial plane extending from the rotational axis of the body, said
leading faces in each row forming at least a portion of the
trailing side of an adjacent waterway; and circumferentially spaced
generally radial rows of generally round cutting elements in said
cutting face interposed between said rows of polyhedron cutting
elements.
15. In a rotary bit as defined in claim 14; said polyhedron cutting
elements being diamonds of cube form; said generally round cutting
elements being diamonds.
16. In a rotary bit as defined in claim 14; said polyhedron cutting
elements being diamonds of cube form; said generally round cutting
elements being diamonds; said diamonds of cube form being disposed
in said cutting face with a negative rake.
17. In a rotary bit adapted to be lowered in a hole on a tubular
drill string: a body having a cutting face for drilling a hole and
passage means for receiving fluid from the drill string; said face
having generally radial waterways communicating with said passage
means and extending to the outer portion of the face and providing
a plurality of lands therebetween extending laterally from an inner
portion of the face to the outer portion of the face;
circumferentially spaced generally radial rows of polyhedron
cutting elements in a plurality of said lands adjacent to at least
some of said waterways, the cutting elements in each row having
leading faces and lower cutting edges disposed in a generally
radial plane extending from the rotational axis of the body, said
leading faces in each row forming at least a portion of the
trailing side of an adjacent waterway; and circumferentially spaced
generally radial rows of generally round cutting elements in a
plurality of said lands adjacent some of said waterways and
interposed between said rows of polyhedron cutting elements.
18. In a rotary bit as defined in claim 17; said polyhedron cutting
elements being diamonds of cube form; said generally round cutting
elements being diamonds.
19. In a rotary bit as defined in claim 17; said polyhedron cutting
elements being diamonds of cube form; said generally round cutting
elements being diamonds; said diamonds of cube form being disposed
in said cutting face with a negative rake.
20. In a rotary bit adapted to be lowered in a hole on a tubular
drill string: a body having a cutting face for drilling a hole and
passage means for receiving fluid from the drill string; said face
having generally radial waterways communicating with said passage
means and extending to the outer portion of the face and providing
a plurality of lands therebetween extending laterally from an inner
portion of the face to the outer portion of the face;
circumferentially spaced generally radial rows of polyhedron
cutting elements in a plurality of said lands adjacent to at least
some of said waterways, the cutting elements in each row having
leading faces and lower cutting edges disposed in a generally
radial plane extending from the rotational axis of the body, said
leading faces in each row forming at least a portion of the
trailing side of an adjacent waterway; circumferentially spaced
generally radial rows of generally round cutting elements in a
plurality of said lands adjacent to the trailing side of some of
said waterways and interposed between said rows of polyhedron
cutting elements; said cutting face having generally radial
waterways adjacent the trailing side of said rows of generally
round cutting elements.
21. In a rotary bit as defined in claim 20; said polyhedron cutting
elements being diamonds of cube form; said generally round cutting
elements being diamonds.
22. In a rotary bit as defined in claim 20; said polyhedron cutting
elements being diamonds of cube form; said generally round cutting
elements being diamonds; said diamonds of cube form being disposed
in said cutting face with a negative rake.
Description
The present invention relates to rotary drill bits, and more
particularly to diamond bits used in the drilling or coring of oil,
gas, water, mining, and similar, bore holes.
Rotary drilling bits embodying generally round diamonds do not
penetrate adequately in the softer, sticky formations, since the
diamonds tend to merely displace and deform the formation, rather
than cut and remove it. In addition, with round diamonds set in the
drilling face of the bit, fluid waterways or channels through which
the drilling fluid is pumped are slightly removed from the cutting
portions of the diamonds, which necessarily displaces the path of
the high velocity flushing fluid flowing through the waterways from
the formation being penetrated by the diamonds, resulting in a
substantial reduction in the assistance of the high velocity
flushing fluid in removing the formation.
In the drilling of evaporite formations, which are relatively
elastic, instead of the formation being cut by round diamonds, or
by the points of diamonds of polyhedron shape, the formation tends
to deflect substantially under the drilling weight or load imposed
on the diamonds, the cutting action of the round or pointed
diamonds being reduced considerably.
By virtue of the present invention, the above difficulties
encountered in drilling softer, sticky formations and evaporite
formations with round diamonds or the point portions of diamonds
are overcome. Diamond drill bits are used in which cubic diamonds
are set in the drilling face or faces of the bit in such manner
that their flat cutting faces are presented to the formation to
effect its removal in the nature of a drag bit. More specifically,
the leading faces of the diamonds and their lower edges are
disposed in generally radial planes extending from the bit axis.
The diamonds are capable of penetrating into the formation to a
much greater extent than round diamonds, and do not merely displace
and deform the formation, which can return elastically to its
initial position after the diamond moves away from it.
The flushing action of the drilling fluid flowing through the drill
bit and through its waterways, and over its ribs or lands defined
by the waterways, is considerably improved since the cubic
diamonds, or diamonds of polyhedron shape, are set in the bit in
such manner that their leading faces form the trailing sides of the
waterways that extend generally from the center or inner portion of
the bit to its gauge portion, the drilling fluid flushing directly
upon and flowing along such leading faces to maintain them in a
clean and cool state.
By virtue of the invention, rotary diamond drill bits can be
provided in which the extent of penetration of the cubic or
polyhedron diamonds is controlled and limited by the inclusion of
round diamonds set in the bit face. These round diamonds limit the
amount of torque required to rotate the bit and, therefore, enable
the torque required for transmission through the drill string to
the bit to be retained at a safe value, thereby avoiding twist-offs
and other types of drill string failures.
By virtue of the use of the cubic diamonds, or polyhedron diamonds
of similar shape, set in the drilling face or faces of the bit in
accordance with the invention, the depth of penetration of the
diamonds, when compared to drill bits with round diamonds, is
greater, to more effectively drill the softer and evaporative types
of formations. The setting of cubic and similar diamonds in
generally radial planes results in the presentation of a much
larger drilling surface for action on the formation than is
available when round diamonds are used, so that fewer cubic or
polyhedron diamonds are required in the bit.
Diamond bits made in accordance with the present invention drill
formations at a faster rate; they drill a greater footage of the
bore hole; and, therefore, effect substantial reductions in
drilling costs. Moreover, drill bits with cubic or similar diamonds
produce larger cuttings, which are conveyed by the flushing fluid
to the top of the well bore, enabling the geologist to identify the
cuttings more readily.
This invention possesses many other advantages, and has other
purposes which may be made more clearly apparent from a
consideration of several forms in which it may be embodied. Such
forms are shown in the drawings accompanying and forming part of
the present specification. These forms 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 combined longitudinal section and side elevational view
of a drill bit embodying one specific form of the invention;
FIG. 2 is an enlarged bottom plan view taken along the line 2--2 on
FIG. 1;
FIG. 3 is an enlarged sectional view taken along the line 3--3 on
FIG. 2, illustrating the drilling action of the drill bit diamonds
on the formation;
FIG. 4 is a bottom plan view of another specific embodiment of the
invention;
FIG. 5 is a bottom plan view of yet a further embodiment of the
invention;
FIG. 6 is an enlarged section taken along the line 6--6 on FIG. 5,
illustrating the cutting actions of the diamonds in the
formation;
FIG. 7 is a bottom plan view of still another form of the
invention; and
FIG. 8 is an enlarged section taken along the line 8--8 on FIG. 7,
illustrating the cutting action of the diamonds of the bit in the
formation.
The diamond drill bit A illustrated in FIg. 1 is capable of
operating upon the bottom of a bore hole, and to flush the cuttings
upwardly around the drill bit and the string of drill pipe B to
which it is secured, which extends to the top of the hole and
through which drilling weight and torque is transmitted to the bit.
The drill bit includes a main body or shank 10 having an upper
threaded pin 11 for threadedly attaching the bit to the lower
threaded box 12 of the string of drill pipe. Drilling fluid is
circulated or pumped down through the drill pipe B, flowing into a
central or main passage 13 in the body of the tool, from where it
flows through a plurality of circumferentially spaced
longitudinally extending ports or openings 14 against the bottom of
the bore hole, and also through distributing channels or waterways
15 that extend laterally across the cutting surface or face 16 of
the bit toward its outer portion, and the side wall of the bore
hole produced by the bit.
In general, the body 10 of the bit includes a matrix portion 17 of
a known type, in which diamonds 18 are secured. As disclosed, the
bit is of the type to drill the entire cross-sectional area of the
bore hole. It is to be understood, however, that the invention is
also applicable to other types of bits, such as core bits, in which
the central portion of the bottom of the hole is not cut, so as to
produce the desired central formation core. As shown, the central
portion 19 of the bit is generally conical in shape, with the sides
of the cone tapering in an upward and inward direction. Such
conical portion merges into a lowermost bottom contacting portion
20, which, in turn, merges into an upwardly divergent conical face
21 that terminates at the reaming face 22 of the bit.
In the specific form of the invention illustrated in FIGS. 1 and 2,
the drilling portions of the bit are divided into a plurality of
diamond set ribs or lands 23 extending from the inner portion of
the bit to its outer reaming face. These ribs or lands are
generally radially arranged and are actually formed and spaced from
each other by lateral generally radial waterways or channels 15
that extend from the central portion of the bit, communicating with
the ports or openings 14 from which they receive drilling fluid.
The fluid flows in a lateral outward direction from each port,
opening or passage 14, through the waterways 15 and into vertical
waterways or grooves 24 in the reaming face of the bit. Some of the
waterways 15 in the drilling face of the bit also extend into
circumferentially spaced junk slots 25 through which cuttings can
pass upwardly, discharging into the annular space between the bit
body and wall of the bore hole above the matrix 17, for continued
upward flow through the annulus between the drill pipe string B and
wall of the bore hole.
The inner portions of the lands or ribs 23 terminate short of the
axis of the drill bit, except for one of the lands which has an
inner portion 23a extending to the axis, and preferably across the
axis 26, to insure the cutting of the bore hole to the bit axis, so
as to prevent the production of a core which might tend to retard
penetration of the bit into the bottom of the hole. Suitable
diamonds 27 are disposed in the inner portion 23a of such rib for
action upon the bottom of the hole, these diamonds being of any
desired configuration. Diamonds 27 of generally round shape are
specifically illustrated in the drawings.
Circumferentially spaced rows 28 of diamonds 18 are set in the end
drilling face of the bit, these diamonds being of polyhedron form.
Preferably, cube diamonds 18 are used, each row of diamonds being
set in a radial rib 23 at the trailing side 15a of a waterway 15,
and with leading faces 18a of the diamonds and their lower edges
18b arranged generally radially of the bit axis 27, with such
leading faces forming the trailing side of the waterway in
conjunction with the intervening matrix material between the
diamonds in each row. As disclosed most clearly in FIG. 3, the cube
diamonds 18 are arranged at the trailing side of each waterway 15
and are set in the matrix 17 preferably with a negative rake, such
that the leading face 18a of each diamond makes an acute angle to
the formation F against which the diamond bears. As an example, the
negative rake can be about 22.degree., each diamond 18 having a
forward tilt in the direction of rotation.
As illustrated specifically in FIG. 2, each row 28 of cube diamonds
18, the diamonds in each row being radially spaced from each other,
is mounted in its generally radial rib 23 at the trailing side of
an adjoining waterway, the row of diamonds extending from the inner
portion to the outer portion of the rib. Each rib that extends
outwardly to the reaming face 22 of the bit has the cube diamonds
18 extending from a longitudinal passage or port 14 to the reaming
face, the vertical ribs 30 defined between the vertical waterways
24 having diamonds 31 of any suitable configuration, such as a
round configuration, set in the reaming face for insuring the
drilling of the bore hole to the desired diameter.
In the drilling of the bore hole, drilling weight is imposed
through the drill pipe string B on the drill bit A while the drill
pipe string and bit are rotated at the desired speed, flushing
liquid being pumped down through the drill pipe string and flowing
through the central bit passage 13 and its ports 14 to the bottom
of the hole, from where it passes laterally through the waterways
15 toward the periphery of the bit. The cube diamonds penetrate
into the formation and effecting its cutting, the drilling fluid
carrying the cuttings through the waterways 15 toward the periphery
of the bit, from where they pass upwardly along the bit and into
the annular space above the matrix 17. The leading or cutting faces
18a and edges 18b of the diamonds produce the cuttings at the
waterways, so that the flushing fluid passing through the waterways
15 at a high velocity are capable of directly removing the cuttings
and sweeping them through the waterways toward the outer portion of
the bit. Such flushing fluid acts directly upon the leading faces
18a of the diamond cutting elements and cleans them thoroughly of
cuttings, as well as cooling the diamonds and adjoining matrix and
maintaining them in a cool state.
Since the leading faces 18a of the diamonds are disposed generally
radially of the bit, they penetrate and cut the formation in the
same manner as a drag bit. Accordingly, a greater penetration is
achieved in relatively soft, sticky formations, and in evaporative
types of formations, to insure the formation of cuttings, the cube
diamonds overcoming the elasticity of such formation materials;
that is to say, the cube diamonds cut the softer or evaporative
types of formations, rather than merely displacing or deforming
them, as occurs in drill bits embodying round diamonds in their
drilling faces. Because of the drag bit-like action of the cube
diamonds 18 on the formation, larger cuttings are produced which
are flushed to the top of the bore hole. The cubic diamonds present
a much larger drilling surface 18a to the formation than round
diamonds, which enables fewer diamonds to be used and the bore hole
drilled at a faster rate. The diamond bit embodying the cube
diamonds 18 is capable of drilling a greater footage of the same
formation when compared with bits embodying round diamonds.
In drill bits of larger diameter, as illustrated in FIG. 4, the
outer portion of the drilling face may be provided with branching
waterways 15b to form additional ribs or lands 23b in which rows
28a of the polyhedron or cube diamonds 18 can be set, in the same
manner as the other rows 28 of diamonds. These diamonds 18 are set
in the ribs 23b at the trailing side of the supplementary waterways
that communicate with the other waterways 15 and also with vertical
waterways provided in the reaming face 22, the diamonds also
preferably being set in the bit face with a negative rake.
In the specific modification of drill bit illustrated in FIG. 4,
the drilling action is the same as in the specific arrangement of
lands, waterways and cube set diamonds illustrated in FIG. 2,
except that more diamonds are available for penetration into the
outer portion of the bottom of the bore hole, for effective
production and removal of the formation cuttings, and to insure a
long effective cutting life of the drill bit in the bore hole.
In certain types of formations, the provision of a drill bit
containing substantially all cube diamonds 18 could result in
excessive penetration of the diamonds in the formation, requiring
the transmission of a comparatively large torque through the drill
pipe string B for the purpose of rotating the drill bit at the
preferred speed. As illustrated in FIGS. 5 and 6, the extent or
depth of penetration of the cubic diamonds 18 is controlled and
limited by the inclusion of round diamonds 40 set in the bit face.
As specifically illustrated, alternate ribs 23 have cube diamonds
18 set therein which combine with the matrix material to define the
trailing faces of adjacent waterways 15. The ribs 23c therebetween
have generally round diamonds 40 set therein at the trailing sides
of the adjacent waterways 15c. The cube diamonds 18 in each row 28
are spaced radially from each other, which is also true of the
round diamonds 40 in each of its rows. However, the cube diamonds
in one row are in staggered relation with respect to the cube
diamonds 18 of another row, such that the cube diamonds in all rows
28 collectively cut upon the entire area of the bottom of the bore
hole. Similarly, the round diamonds 40 in each row 28d are radially
spaced from each other and are in staggered relation with respect
to the round diamonds in another row, such that the several rows
28d of diamonds 40 collectively cover substantially the entire area
of the bottom of the bore hole upon rotation of the drill bit.
In general, the drill bit illustrated in FIGS. 5 and 6 operates in
the same manner as the drill bits illustrated in FIGS. 1-4, except
that the round diamonds 40 are incapable of penetrating into the
formation to the same extent as the cube diamonds 18. As a result,
a limit is placed upon the amount of torque required to rotate the
bit with the appropriate drilling weight imposed thereon, so that
twist-offs and other failures of the drill pipe string B are
avoided.
The appropriate setting and retention of the round diamonds 40 in
the matrix 17 of the drill bit necessitates the cutting portion 40a
of each round diamond, that extends outwardly from the matrix 17,
to be displaced away from the side of the waterway 15c, which is
particularly evident from FIG. 6. This is to be compared to the
leading face 18a of the cube diamond 18 which provides the actual
trailing side of the waterway 15, enabling the flushing liquid to
act directly upon the diamond 18 for the purpose of removing any
cuttings that tend to adhere thereto and to flush the cuttings not
only from the leading faces of the diamonds but from the bottom of
the hole. This direct action of the drilling fluid upon the bottom
of the hole also assists the cube diamonds in producing the
cuttings, since the high velocity fluid is acting directly upon the
bottom F of the hole where the cutting action by the cube diamonds
is occurring.
In the embodiment of invention illustrated in FIGS. 7 and 8,
essentially the same combination of cube diamonds 18 and round
diamonds 40 is disclosed as presented in FIGS. 5 and 6, the bit
operating in the same manner. HOwever, additional flushing fluid is
caused to pass along each row 28d of round diamonds 40 by providing
waterways 15e, 15f immediately adjacent thereto and on each side of
each row. Thus, the drilling fluid will flow through leading and
trailing waterways 15e, 15f on opposite sides of each row 28d of
round diamonds to cool and clean such diamonds of cuttings and to
flush the cuttings toward the perimeter of the bit.
In all forms of diamond drill bits illustrated, the cube diamond 18
and also the round diamond 40 can be set in various manners. Thus,
the cube diamonds 18 in each row can be set closely adjacent to
each other, or spaced to any desired extent from one another, the
rows of diamonds being staggered with respect to one another. As an
example, FIG. 2 illustrates a closer, fairly heavy setting of the
cube diamonds 18; whereas, FIG. 5 illustrates a widely spaced, or
light setting, of the cube diamonds in each row, the same being
true of the diamonds in each row 28d of round diamonds 40.
Moreover, the size of the diamonds used can be varied to suit
various drilling conditions.
* * * * *