U.S. patent application number 15/738169 was filed with the patent office on 2018-07-12 for roller cone drill bit journal with asymmetric ball race and extended friction race.
The applicant listed for this patent is Halliburton Energy Services, Inc.. Invention is credited to Micheal Burl Crawford, Young Ho Lee.
Application Number | 20180195347 15/738169 |
Document ID | / |
Family ID | 57834266 |
Filed Date | 2018-07-12 |
United States Patent
Application |
20180195347 |
Kind Code |
A1 |
Lee; Young Ho ; et
al. |
July 12, 2018 |
ROLLER CONE DRILL BIT JOURNAL WITH ASYMMETRIC BALL RACE AND
EXTENDED FRICTION RACE
Abstract
The present disclosure relates to roller cone drill bit journals
with asymmetric ball races and extended friction races. The
disclosure also relates to methods of forming such journals, and
methods of finishing these journals to produce finished journals
with symmetric ball races.
Inventors: |
Lee; Young Ho; (Conroe,
TX) ; Crawford; Micheal Burl; (Montgomery,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Halliburton Energy Services, Inc. |
Houston |
TX |
US |
|
|
Family ID: |
57834266 |
Appl. No.: |
15/738169 |
Filed: |
July 21, 2015 |
PCT Filed: |
July 21, 2015 |
PCT NO: |
PCT/US2015/041230 |
371 Date: |
December 20, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16C 17/02 20130101;
E21B 10/08 20130101; F16C 2352/00 20130101; E21B 10/22
20130101 |
International
Class: |
E21B 10/22 20060101
E21B010/22; F16C 17/02 20060101 F16C017/02 |
Claims
1. A roller cone drill bit journal comprising: a ball race; a
friction race; and a protuberance that extends the friction race
into an area to be occupied by the ball race in a finished journal
and that renders the ball race in the journal asymmetric.
2. The roller cone drill bit journal of claim 1 further comprising
a weld pool located on or within the protuberance.
3. The roller cone drill bit journal of claim 1 further comprising
a weld pool and bearing material located on the friction race.
4. The roller cone drill bit journal of claim 1, wherein the
protuberance is circular or ovoid in cross-section.
5. The roller cone drill bit journal of claim 1, wherein the
protuberance is angular in cross-section.
6. The roller cone drill bit journal of claim 1, wherein the
protuberance extends into the ball race of the journal by up to 90%
of the diameter of the ball race in the finished journal.
7. The roller cone drill bit journal of claim 1, wherein the
protuberance extends into the ball race of the journal by at least
0.05% of the diameter of the ball race in the finished journal.
8. A method of forming a journal for a roller cone drill bit, the
method comprising: forming a journal, comprising: a ball race; a
friction race: and a protuberance that extends the friction race
into an area to be occupied by the ball race in a finished journal
and that renders the ball race in the journal asymmetric; welding
bearing material to the friction race using a weld pool; and
removing the protuberance and any weld pool or bearing material
located on or in the protuberance to form a symmetric ball
race.
9. The method of claim 8, wherein the protuberance is circular or
ovoid in cross-section.
10. The method of claim 8, wherein the protuberance is angular in
cross-section.
11. The method of claim 8, wherein the protuberance extends into
the ball race of the journal by up to 90% of the diameter of the
ball race in the finished journal.
12. The method of claim 8, wherein the protuberance extends into
the ball race of the journal by at least 0.05% of the diameter of
the ball race in the finished journal.
13. The method of claim 8, wherein, during welding, the weld pool
is placed on top of the protuberance.
14. The method of claim 8 wherein, during welding, the weld pool
melts at least a portion of the protuberance.
15. The method of claim 8, wherein, during welding, the weld pool
replaces at least a portion of the protuberance.
16. The method of claim 8 wherein, during welding, the weld pool
reaches a temperature sufficiently high to damage the ball race if
the weld pool contacts the ball race.
17. The method of claim 8, wherein, during welding, the weld pool
does not contact the ball race.
18. The method of claim 8, wherein the bearing material is at least
1% thicker along the at least an area of the friction race than in
an otherwise identical bit with no protuberance.
19. The method of claim 8, wherein the bearing material is at least
1% thicker along the entire friction race than in an otherwise
identical bit with no protuberance.
20. The method of claim 8, wherein removing the protuberance and
any weld pool or bearing material located on or in the protuberance
comprises machining.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to roller cone drill bit
journals, methods of forming journals, and method of finishing
journals.
BACKGROUND
[0002] Roller cone drill bits are used to form wellbores through
formations in the earth in order to access downhole materials, such
as petrochemical deposits. Roller cone drill bits are typically
formed in a primary shape using a machining process, resulting in a
bit body. The bits are then finished by placing specialized
materials in selected locations and by tooling, including
machining, selected locations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] A more complete and thorough understanding of the present
embodiments and advantages thereof may be acquired by referring to
the following description taken in conjunction with the
accompanying drawings, which are not to scale, in which like
reference numbers indicate like features, and wherein:
[0004] FIG. 1 is a schematic drawing in cross-section of a finished
journal of a roller cone drill bit;
[0005] FIG. 2 is a schematic drawing in cross-section of the
finished journal of FIG. 1 with a roller cone, also depicted in
cross section, assembled on the journal;
[0006] FIG. 3A is a schematic drawing in cross-section of a roller
cone drill bit journal with an asymmetric ball race and an extended
friction race;
[0007] FIG. 3B is a schematic drawing in cross-section of the
asymmetric roller cone drill bit journal of FIG. 3A superimposed
over a conventional roller cone drill bit journal;
[0008] FIG. 3C is a schematic drawing in cross-section of a roller
cone drill bit journal of FIG. 3A superimposed over the finished
journal of FIG. 1;
[0009] FIG. 4 is a schematic drawing in elevation showing a roller
cone drill bit incorporating teachings of the present disclosure;
and
[0010] FIG. 5 is a schematic drawing in section and in elevation
with portions broken away showing examples of wellbores which may
be formed by a roller cone drill bit incorporating teachings of the
present disclosure.
DETAILED DESCRIPTION
[0011] The present disclosure relates to roller cone drill bit
journals having an extended friction race and an asymmetric ball
race and to method of forming and further finishing this type of
journal to produce a finished journal. The journal having an
extended friction race and an asymmetric ball race may be a journal
at any stage prior to the finished journal. For instance, it may be
a journal that has not been heat-treated or a heat-treated journal
that has not undergone other finishing processes.
[0012] A roller cone drill bit contains at least one arm 10, as
shown in FIG. 1. This arm 10 includes a journal 20, with a ball
race 30 and a friction race 40. Friction race 40 and ball race 30
are adjacent on journal 20. When arm 10 is fully assembled, as
shown in FIG. 2, cone 50, which contains a plurality of cutting
elements 60, is disposed on journal 20 so that it may rotate about
journal 20 when the drill bit is in use. Retaining balls 70 are
fitted into ball race 30 to retain cone 50 on journal 20. Friction
race 40 is covered with a bearing material (not independently
shown). Other functional features, exemplified by sealing rings 80
for a lubricant system (not otherwise shown), are also added
depending on the overall bit design.
[0013] Journal 20 is first formed as a journal then finished prior
to assembly with cone 50. Finishing often includes welding the
bearing material to friction race 40. During this process, the weld
pool sometimes spills off of friction race 40 into adjacent ball
race 30, removing part of ball race 30 in the process. This damage
to ball race 30 renders it unable to appropriately house retaining
balls 70, particularly during use of the roller cone drill bit. As
a result, the entire arm 10 with a damaged ball race 30 is
discarded.
[0014] In the present disclosure, a journal friction race 40 is
formed with a protuberance 100 that distorts ball race 30 into an
asymmetric shape as shown in FIG. 3A. FIG. 3B illustrates how
protuberance 100 of a journal of the present disclosure (solid
line) extends into the ball race 30 as compared to a conventional
journal (dashed line).
[0015] If the weld pool spills over from friction race 40, it
encounters and damages protuberance 100. In most instances, this
damage has no effect on the ability to produce a usable finished
journal 20 because protuberance 100 (solid line) is later removed
and is not present in the finished journal (dotted line), as may be
seen in FIG. 3C.
[0016] In addition, because of decreased concerns about the weld
pool spilling from friction race 40 into ball race 30, more bearing
material may be applied to friction race 40. This additional
bearing material may be applied to portions of friction race 40
that tend to experience more radial load or other stress during use
of the drill bit.
[0017] Journal 20 is typically formed with arm 10 using
conventional methods, such as machining. In such methods, a bit
material is machined having the journal dimensions and
configuration. They may also be formed in a multi-step process,
such as when a first material is machined, then filled with a
binder or infiltrant. Other materials that become integral with the
bit may also be welded to the journal. In general, journal 20 and
arm 10 may be formed from steel, a steel alloy, a matrix material,
or other suitable bit material with suitable strength, toughness
and machinability. The journal may be machined to form ball race 30
and protuberance 100, allowing removal of journal 20 followed by
removal of the proturberance from ball race 30 in order to finish
the ball race and prevent the weld pool from damaging ball race
30.
[0018] Journal 20 is then finished prior to assembly with cone 50.
The remainder of arm 10 may also be finished prior to assembly with
cone 50, although some finishing of arm 10 may also occur after
assembly with cone 50, so long as the cone does not interfere with
later finishing.
[0019] In particular, a bearing material may be applied to friction
race 40. This bearing material, typically when combined with other
bearing material on cone 50, forms a bearing that facilitates
rotation of cone 50 around journal 20 when the roller cone drill
bit is in use. Suitable bearing materials include hard metals, such
as metal borides, metal carbides, metal oxides, and metal nitrides.
One common bearing material is tungsten carbide (WC or W.sub.2C).
The bearing material must be sufficiently attached to friction race
40 to withstand the radial load and other forces the bearing
experiences during drill bit use. Typically, the bearing material
is welded to friction race 40 using a welding material.
[0020] During the welding process, a portion of both the bearing
material and friction race 40 are heated to their melting points. A
molten welding material may also applied between them. The molten
bearing material, friction rate, and welding material, if present,
combine to form the weld pool, which coalesces as to cools, forming
a strong bond between the bearing material and the friction race.
Suitable welding materials may very depending on the composition of
the friction race, the bearing material, and the welding material.
For a steel friction race and a tungsten carbide bearing material a
welding material with reduced friction and increased load capacity
as compared to base steel may be used. For instance, an alloy
containing cobalt, nickel, iron, aluminium, boron, carbon,
chromium, manganese, molybdenum, phosphorus, sulfur, silicon,
titanium, of mixtures thereof, such as a STELLITE.RTM. (Kennametal
Stellite, Goshen, Ind.) alloy, may be used. The welding temperature
is also determined by the melting point of the welded components
and the welding material. Typical welding temperatures are between
700.degree. F. and 1100.degree. F.
[0021] During welding, the weld pool may expand onto protuberance
100, removing or damaging some of the protuberance material and, in
some cases, replacing it with a different material. After welding,
journal 20 is machined to final dimensions as shown in FIG. 3C.
During this machining process, any remaining portions of
protuberance 100, including any damaged material, as well as any
different replacement material are all removed to form ball race 30
with a finished configuration. This finished configuration is
symmetric and typically circular or ovoid in cross-section.
[0022] Although the exact dimensions of protuberance 100 may vary,
it may extend into ball race 30 by up to 90% of the diameter of
finished ball race 30. It may alternatively extend into ball race
30 by up to up to 75%, or up to 50%, up to 33%, up to 25%, or up to
10%, of the diameter of finished ball race 30. In order to ensure
adequate protection of ball race 30, protuberance 100 may extent
into ball race 30 by at least 0.05%, at least 0.1%, at least 1%, at
least 5%, at least 10%, at least 25%, at least 33%, at least 50%,
at least 75%, or at least 90% of the diameter of finished ball race
30.
[0023] Protuberance 100 may have a circular or ovoid cross-section,
as shown in FIG. 3, or it may have an angled cross-section, such as
a triangular cross-section, or any other shape that facilitates
removal of journal 20 from any machining used to form it with ball
race 30 and protuberance 100 intact.
[0024] In addition, because friction race 40 extends along with
protuberance 100, the bearing material may be applied on or very
close to protuberance 100. Bearing material on protuberance 100 may
simply be removed during the machining process to form ball race
30. As a result, in finished journal 20, the bearing material may
be present on friction race 40 substantially flush with ball race
30, or set back less than 0.1 inches, less than 0.05 inches, ore
less than 0.01 inches from ball race 30.
[0025] Compared to a bit with no protuberance, protuberance 100
allows additional bearing material, such as additional wear
resistant or anti-galling material, to be placed along all of the
friction race of journal 20, or at least in an area of journal 20
adjacent protuberance 100 or in an area of journal 20 that that
experiences concentrated stress or high wear. This may increase the
wear resistance or other stress tolerance of the bearing as
compared to similar bits in which there is no protuberance 100 on
the journal 20. The additional bearing material may be at least 1%
thicker, at least 10% thicker, at least 20% thicker, at least 30%
thicker, at least 50% thicker, or at least 100% thicker than the
bearing material in a bit with no protuberance.
[0026] After journal 20 is finished, cone 50 may be assembled on it
as shown in FIG. 2. by placing retaining balls 70 in ball race 30.
Prior to or after cone 50 assembly, arm 10 may be attached to bit
body 210 optionally along with one or a plurality of other arms 10
as shown in FIG. 4 to form a roller cone drill bit 200. Bit body
210 has a tapered, externally threaded, upper portion 230
satisfactory for use in attaching roller cone drill bit 200 with a
drill string (as further described with respect to FIG. 5) to allow
rotation of roller cone drill bit 200 in response to rotation of
the drill string (as further described with respect to FIG. 5).
[0027] FIG. 9 is a schematic drawing in elevation and in section
with portions broken away of wellbores or boreholes which may be
formed in a formation by roller cone drill bits incorporating
teachings of the present disclosure. Various aspects of the present
disclosure may be described with respect to a drilling rig 300
located at well surface 310. Various types of drilling equipment
such as a rotary table, mud pumps and mud tanks (not expressly
shown) may be located at well surface 310. Drilling rig 300 may
have various characteristics and features associated with a land
drilling rig. However, roller cone drill bits incorporating
teachings of the present disclosure may be satisfactorily used with
drilling equipment located on offshore platforms, drill ships,
semi-submersibles and drilling barges (not expressly shown).
[0028] Roller cone drill bit 200 may be attached with the end of
drill string 320 extending from well surface 310. Drill string 320
may apply weight to and rotate roller cone drill bit 200 to form
wellbore 330. Drill string 320 may be formed from sections or
joints of generally hollow, tubular drill pipe (not expressly
shown). Drill string 320 may also include bottom hole assembly 340
formed from a wide variety of components. Drill string 320 and
roller cone drill bit 200 may be used to form various types of
wellbores and/or boreholes. For example, a directional or
horizontal wellbore as shown in FIG. 5 in dotted lines, may be
formed as an alternative to vertical wellbore 330.
[0029] The present disclosure is not limited to roller cone drill
bits associated with conventional drill strings. In addition,
although FIGS. 4 and 5 illustrate a drill bit having only cones,
the present disclosure may also be used in hybrid bits which
combine both cones and fixed cutters and/or blades.
[0030] The present disclosure provides an embodiment A relating to
an roller cone drill bit journal including a ball race, a friction
race, and a protuberance that extends the friction race into an
area to be occupied by the ball race in a finished journal and that
renders the ball race in the journal asymmetric.
[0031] The present disclosure provides an embodiment B relating to
a method of forming a journal for a roller cone drill bit by
forming a journal as described in embodiment A, welding bearing
material to the friction race using a weld pool, and removing the
protuberance and any weld pool or bearing material located on or in
the protuberance to form a symmetric ball race.
[0032] In addition, embodiments A and B may be used in conjunction
with the following additional elements, which may also be combined
with one another unless clearly mutually exclusive, and which
method elements may be used to obtain devices and which device
elements may result from methods: i) a weld pool may be located on
or within the protuberance; ii) a weld pool and bearing material
may be located on the friction race; iii) the protuberance may be
circular or ovoid in cross-section; iv) the protuberance may be
angular in cross-section; v) the protuberance may extend into the
ball race of the journal by up to 90% of the diameter of the ball
race in the finished journal; vi) the protuberance may extend into
the ball race of the journal by at least 0.05% of the diameter of
the ball race in the finished journal; vii) the protuberance may be
circular or ovoid in cross-section; viii) the protuberance may be
angular in cross-section; ix) the protuberance may extend into the
ball race of the journal by up to 90% of the diameter of the ball
race in the finished journal; x) the protuberance may extend into
the ball race of the journal by at least 0.05% of the diameter of
the ball race in the finished journal; xi) during welding, the weld
pool may be placed on top of the protuberance; xii) during welding,
the weld pool may melt at least a portion of the protuberance;
xiii) during welding, the weld pool may replace at least a portion
of the protuberance; xiv) during welding, the weld pool may reach a
temperature sufficiently high to damage the ball race if the weld
pool contacts the ball race; xv) during welding, the weld pool may
not contact the ball race; xvi) the bearing material may be at
least 1% thicker along the at least an area of the friction race
than in an otherwise identical bit with no protuberance; xvii) the
bearing material may be at least 1% thicker along the entire
friction race than in an otherwise identical bit with no
protuberance; xviii) machining may be use to remove the
protuberance and any weld pool or bearing material located on or in
the protuberance.
[0033] Although the present disclosure and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alternations can be made without departing from
the spirit and scope of the disclosure.
* * * * *