U.S. patent application number 10/954106 was filed with the patent office on 2005-05-26 for flat and bevel chipbreaker insert.
This patent application is currently assigned to Baker Hughes Incorporated. Invention is credited to Bradford, Francine A., Hart, Daniel R., Stowe, Calvin J..
Application Number | 20050109546 10/954106 |
Document ID | / |
Family ID | 34652358 |
Filed Date | 2005-05-26 |
United States Patent
Application |
20050109546 |
Kind Code |
A1 |
Stowe, Calvin J. ; et
al. |
May 26, 2005 |
Flat and bevel chipbreaker insert
Abstract
A cutting insert for use on a metal cutting tool downhole in an
oil or gas well, with at least one land on a leading edge of the
insert, and at least one bevel surface angled relative to the axis
of the insert and rising above the adjacent land in the direction
of travel of the insert. Multiple bevels and lands can be used on
each insert, and multiple inserts can be used on each tool.
Inventors: |
Stowe, Calvin J.; (Houston,
TX) ; Hart, Daniel R.; (Sugarland, TX) ;
Bradford, Francine A.; (Houston, TX) |
Correspondence
Address: |
GERALD W SPINKS
P. O. BOX 2467
BREMERTON
WA
98310
US
|
Assignee: |
Baker Hughes Incorporated
Houston
TX
|
Family ID: |
34652358 |
Appl. No.: |
10/954106 |
Filed: |
September 28, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60525577 |
Nov 26, 2003 |
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Current U.S.
Class: |
175/426 |
Current CPC
Class: |
E21B 10/5673
20130101 |
Class at
Publication: |
175/426 |
International
Class: |
E21B 010/36 |
Claims
We claim:
1. A metal cutting insert for use on a downhole tool in an oil or
gas well, said insert comprising: a solid body, said body having an
axis; a rear face on said body, for mounting said body to a
downhole type metal cutting tool; a front face on said body,
opposite said rear face, for presentation to a downhole metal
object to be cut; a plurality of lands formed on said front face of
said body, each said land being substantially orthogonal to said
axis of said body; and a plurality of bevels formed on said front
face of said body, each said bevel being angled relative to said
axis of said body, forward of an adjacent said land.
2. The metal cutting insert recited in claim 1, wherein each said
land is angled no less than 75 degrees relative to said axis of
said body.
3. The metal cutting insert recited in claim 1, wherein each said
bevel is angled between 20 degrees and 70 degrees relative to said
axis of said body.
4. The metal cutting insert recited in claim 1, wherein a first
said land is formed at an edge of said front face.
5. The metal cutting insert recited in claim 4, wherein a first
said bevel is formed adjacent to said first land.
6. The metal cutting insert recited in claim 5, wherein said
plurality of lands and said plurality of bevels are formed at
alternating locations across said front face.
7. The metal cutting insert recited in claim 1, wherein: each said
land is a substantially planar rectilinear surface; and each said
bevel is a substantially planar rectilinear surface.
8. The metal cutting insert recited in claim 7, wherein said insert
body is a substantially rectilinear solid.
9. The metal cutting insert recited in claim 1, wherein: each said
land is a substantially planar annular surface; and each said bevel
is a substantially frusto-conical surface.
10. The metal cutting insert recited in claim 9, wherein said
insert body is substantially cylindrical.
11. A downhole metal cutting tool for gas or oil wells, comprising:
a tool body adapted for lowering into an oil or gas well to
rotatingly cut a downhole metal object; at least one metal cutting
insert for mounting on said downhole tool body, said at least one
insert having a solid body with an axis; a front face on said at
least one insert body, for presentation to said downhole metal
object; at least one land formed on said front face of said at
least one insert body, said at least one land being substantially
orthogonal to said axis of said at least one insert body; and at
least one bevel formed on said front face of said at least one
insert body, said at least one bevel being angled above said at
least one land, relative to said axis of said at least one insert
body.
12. The downhole metal cutting tool recited in claim 11, further
comprising: a plurality of said lands; and a plurality of said
bevels; wherein said plurality of lands and said plurality of
bevels are formed at alternating locations across said front face
of said at least one insert body.
13. The downhole metal cutting tool recited in claim 12, wherein: a
first said land is formed at an edge of said front face of said at
least one insert body; and a first said bevel is formed adjacent to
said first land.
14. The downhole metal cutting tool recited in claim 12, wherein
each said land is angled no less than 75 degrees relative to said
axis of said at least one insert body.
15. The downhole metal cutting tool recited in claim 12, wherein
each said bevel is angled between 20 degrees and 70 degrees
relative to said axis of said at least one insert body.
16. The downhole metal cutting tool recited in claim 12, wherein:
each said land is a substantially planar rectilinear surface; and
each said bevel is a substantially planar rectilinear surface.
17. The downhole metal cutting tool recited in claim 16, wherein
said insert body is a substantially rectilinear solid.
18. The downhole metal cutting tool recited in claim 12, wherein:
each said land is a substantially planar annular surface; and each
said bevel is a substantially frusto-conical surface.
19. The downhole metal cutting tool recited in claim 18, wherein
said insert body is substantially cylindrical.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 60/525,577, filed on Nov. 26, 2003, and
entitled "Flat and Bevel Chipbreaker Insert."
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] This invention is in the field of tools used downhole, in
oil or gas wells, to mill or otherwise cut metal objects in the
borehole.
[0005] 2. Background Art
[0006] In the drilling, completion, or re-work of an oil or gas
well, it often becomes necessary to cut into or through a metal
object which is located downhole in the well bore. This can be
required, for instance, in cutting through the wall of a well
casing, removing a packer, or milling away some other metal
obstruction which may be present in the borehole. This type of
cutting or milling operation is very different from the type of
metal cutting operations typically found in a machine shop
environment. The downhole metal cutting operation involves the
rotation of a very large tool by a very heavy workstring, by
comparison with the typical machine shop operation. The downhole
cutting operation itself involves a great deal of vibration and
even severe impact, between the cutting tool and the metal object
being cut. In fact, much of the force of any such impact or
vibration is typically brought to bear directly on the cutting
insert or inserts which are mounted on the cutting face of the
downhole cutting tool. These cutting inserts are essentially the
"teeth" of the cutting tool. They are typically made of a very hard
material, such as tungsten carbide.
[0007] The operator can not closely observe the downhole cutting
operation and monitor the condition of the cutting insert or
inserts. By contrast, the machine shop operator can closely observe
the cutting operation as it progresses, and he can change the
cutting insert regularly as its cutting surfaces degrade. Stopping
the operation in the machine shop is typically significantly
cheaper than pulling a downhole tool from the well bore and
checking or changing the tool out. This means that the typical
machine shop operation is always done with a basically fresh
cutting insert in good condition.
[0008] The downhole operator, on the other hand, must simply rotate
the workstring and rely upon fairly remote indicators of the
performance of the tool, such as vibration and rate of penetration,
to judge the progress of the cutting operation. As a result, as the
cutting operation continues, the cutting insert on the face of the
cutting tool usually wears away and disintegrates. It is common, in
fact, to have multiple cutting inserts on a downhole cutting tool,
with the inserts being arranged progressively across the cutting
face of the tool. This is done so that, as each cutting insert
wears away and disintegrates or falls off the tool, another
adjacent cutting insert establishes contact with the work piece,
thereby continuing the cutting action. This alleviates the need to
pull the work string and replace the tool, or at least delays the
necessity of replacing the tool.
[0009] An unfortunate aspect of this situation is that each cutting
insert must remain effective in spite of having its original
cutting geometry drastically changed as the cutting operation
progresses; that is, the insert will not retain its original
cutting edge for very long. If the cutting insert wears to such an
extent that the cutting edge is gone, the portion of the insert
contacting the work piece can act as a bearing surface. If the
cutting insert can not cut effectively after having its original
cutting edge worn away, the insert will not be an effective part of
the tool, and it can even impede the action of nearby cutting
inserts, by acting as a bearing surface, rather than as a cutting
surface.
[0010] It is also known to provide a chip breaking feature on the
forward face of a cutting insert for use in the downhole
environment, which causes the insert to break off metal chips from
the work piece at short lengths, allowing the chips to be more
easily removed from the well bore by the flow of drilling fluid.
So, as wear progresses across the insert face, through the chip
breaking feature, the insert might cease to break off short chips
and begin to produce long, thin metal turnings. The long thin
turnings are not easily removed from the well bore by the flow of
fluid, so this type of insert wear can lead to the clogging of the
area around the cutting tool, preventing further penetration of the
work piece. Further, if the chip breaking feature contributes in
any way to the fragility of the insert body, it can cause the
insert to disintegrate prematurely and fall off the cutting tool,
resulting in a complete loss of the ability to cut, until the tool
body wears sufficiently to allow the adjacent cutting insert to
come into play.
[0011] It is desirable to have, therefore, a cutting insert which
is sufficiently robust to withstand the impacts experienced in the
downhole environment, and which is designed to break off short
metal chips from the work piece, and to continue to present an
effective cutting geometry to the work piece, even as the original
cutting geometry of the insert gradually wears away.
BRIEF SUMMARY OF THE INVENTION
[0012] The present invention, in summary, is a downhole cutting
insert which has one or more lands on its cutting face,
interspersed with one or more beveled surfaces, creating a robust
cutting face on the insert. The juxtaposition of bevels with lands
causes the insert to break off metal chips from the work piece at
short lengths, allowing the chips to be more easily removed from
the well bore by the flow of drilling fluid. Use of alternating
multiple bevels and lands allows the insert to continue to
effectively form short metal chips, even as the forward face and
the edge of the insert gradually degrade.
[0013] The novel features of this invention, as well as the
invention itself, will be best understood from the attached
drawings, taken along with the following description, in which
similar reference characters refer to similar parts, and in
which:
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0014] FIG. 1 is an elevation view of a downhole cutting tool which
can incorporate a cutting insert according to the present
invention;
[0015] FIG. 2 is a top or front elevation view of a first
embodiment of a cutting insert according to the present
invention;
[0016] FIG. 3 is a top or front elevation view of a second
embodiment of a cutting insert according to the present
invention;
[0017] FIG. 4 is a partial axial section view of a third embodiment
of a cutting insert according to the present invention;
[0018] FIG. 5 is a partial axial section view of a fourth
embodiment of a cutting insert according to the present
invention;
[0019] FIG. 6 is a partial axial section view of the cutting insert
shown in FIG. 2 or FIG. 3; and
[0020] FIG. 7 is a partial axial section view of a fifth embodiment
of a cutting insert according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] As illustrated in FIG. 1, a cutting insert according to the
present invention can be mounted on a cutting tool 10 designed for
use in cutting metal objects downhole, in an oil or gas well. The
cutting tool 10 can be a pilot mill, junk mill, casing cutter,
window mill, or any other type of downhole cutting tool. The
cutting tool 10 has a tool body 12, which is adapted to mount to a
work string WS. The tool body 12 has at least one cutting feature,
such as the blades 14, attached thereto or formed thereon. Each
cutting feature or blade 14 has at least one cutting insert 20
mounted on a cutting face 16 thereof, and oriented to face in the
direction 18 in which the blades 14 and the cutting inserts 20 will
advance when the cutting tool 10 is rotated. Advancement in the
direction 18 will cause the cutting inserts 20 to advance toward
and into the downhole metal object or work piece (not shown).
[0022] The cutting inserts 20 can take various shapes, some of
which will be designated as 20, 20A and 20B in the Figures
discussed below. Other shapes can also be used without departing
from the spirit of the present invention, as long as they exhibit
the features described below. FIG. 2 shows the forward or front
elevation of a round or cylindrical cutting insert 20A, oriented in
the drawing the same as the orientation of the cutting inserts 20
on the right hand blade 14 in FIG. 1. Where a round or cylindrical
insert is discussed herein, it should be understood that a
half-round or otherwise partially round insert can also be
intended, where the context allows. The cutting insert 20A has at
least one land 22A and at least one bevel or beveled surface 24A,
with a first land 22A being located immediately next to the
original leading edge 28A of the cutting insert 20A. Where present,
successive lands 22A and bevels 24A are alternatingly arranged from
the leading edge 28A toward the axis A of the cutting insert 20A.
The cutting insert 20A is shown with three lands 22A and three
bevels 24A, but it can have any number of each. The cutting insert
20A can also have a surface 26A substantially orthogonal to the
axis A, on the front face of the insert 20A.
[0023] As illustrated in FIG. 3, the cutting insert 20 can also
have a rectilinear shaped body, such as the insert 20B. The cutting
insert 20B is shown oriented in the drawing the same as the
orientation of the cutting inserts 20 on the right hand blade 14 in
FIG. 1. Where a rectilinear insert is discussed herein, it should
be understood that a square or otherwise rectangular insert can be
intended. The cutting insert 20B has at least one land 22B and at
least one bevel or beveled surface 24B, with a first land 22B being
located immediately next to the original leading edge 28B of the
cutting insert 20B. Where present, successive lands 22B and bevels
24B are alternatingly arranged from the leading edge 28B toward the
axis of the cutting insert 20B. The cutting insert 20B is shown
with three lands 22B and three bevels 24B, but it can have any
number of each. The cutting insert 20B can also have a surface 26B
substantially orthogonal to the axis, on the front face of the
insert 20B.
[0024] FIG. 4 shows the most basic illustration of the features of
the lands 22 and bevels 24 on the inserts 20 shown in FIGS. 2 and
3, or on any insert 20 according to the present invention. The
insert 20 has a solid body. Each land 22 is a substantially flat
surface which is substantially orthogonal to the axis of the
cutting insert 20. Each land can be, more specifically, angled
between approximately 75 degrees and approximately 90 degrees
relative to the insert axis. It can be seen that, on the round
insert 20A shown in FIG. 2, the land 22A would be a substantially
planar, annular, surface, substantially or nearly orthogonal to the
axis of the cutting insert 20A. It can further be seen that, on the
rectilinear insert 20B shown in FIG. 3, the land 22B would be a
substantially planar, rectangular or otherwise rectilinear,
surface, substantially or nearly orthogonal to the axis of the
cutting insert 20B.
[0025] Each bevel 24 is angled forward, or in the direction 18 of
rotation, above or forward of the outwardly adjacent land 22 by a
distance 32, at an angle 34 from a plane orthogonal to the axis of
the cutting insert 20. The angle 34 can be between approximately 20
degrees and approximately 70 degrees, with a preferred angle of
approximately 45 degrees. Put another way, the bevel 24 is also
angled relative to the axis of the cutting insert 20, by an angle
between approximately 20 degrees and approximately 70 degrees, with
a preferred angle of approximately 45 degrees. A representative
raised distance 32 could be on the order of approximately 0.015
inch. It can be seen that, on the round insert 20A shown in FIG. 2,
the bevel 24A would be a substantially frusto-conical surface,
angled relative to the axis of the cutting insert 20A. It can
further be seen that, on the rectilinear insert 20B shown in FIG.
3, the bevel 24B would be a substantially planar, rectangular or
otherwise rectilinear, surface, angled relative to the axis of the
cutting insert 20B. The cutting insert 20 can also have a relief
angle 36 between approximately 3 degrees and approximately 9
degrees, which promotes the cutting action of the edge 28 into the
work piece. A rear face 40 is provided for mounting the cutting
insert 20 on the cutting feature or blade 14 of the cutting tool
10.
[0026] The distance 32 by which each bevel 24 rises above its
outwardly adjacent land 22 terminates the bevel 24 either in the
surface 26 or in an inwardly adjacent land 22, as shown in FIG. 5,
in which the cutting insert 20 has two lands 22 and two bevels 24.
This embodiment has been found to be somewhat more robust in
resisting impact than the single land, single bevel embodiment
shown in FIG. 4. As shown in FIG. 6, the cutting insert 20 can have
three sets of lands 22 and bevels 24, or even more. Each land can
be relatively narrow, for example, in the range of approximately
0.004 inch to approximately 0.060 inch. As shown in FIG. 7, the
cutting insert 20 can also have other features on its leading face
26, such as a depression 38.
[0027] While the particular invention as herein shown and disclosed
in detail is fully capable of obtaining the objects and providing
the advantages hereinbefore stated, it is to be understood that
this disclosure is merely illustrative of the presently preferred
embodiments of the invention and that no limitations are intended
other than as described in the appended claims.
* * * * *