GB2310443A - Leg wear protection for roller cone rock bits - Google Patents
Leg wear protection for roller cone rock bits Download PDFInfo
- Publication number
- GB2310443A GB2310443A GB9703368A GB9703368A GB2310443A GB 2310443 A GB2310443 A GB 2310443A GB 9703368 A GB9703368 A GB 9703368A GB 9703368 A GB9703368 A GB 9703368A GB 2310443 A GB2310443 A GB 2310443A
- Authority
- GB
- United Kingdom
- Prior art keywords
- leg
- legs
- protect
- inserts
- diamond
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000011435 rock Substances 0.000 title claims abstract description 48
- 229910003460 diamond Inorganic materials 0.000 claims abstract description 39
- 239000010432 diamond Substances 0.000 claims abstract description 39
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000000314 lubricant Substances 0.000 claims abstract description 10
- 238000005299 abrasion Methods 0.000 claims abstract description 6
- 238000005461 lubrication Methods 0.000 claims description 12
- 230000000717 retained effect Effects 0.000 claims description 8
- 238000005520 cutting process Methods 0.000 claims description 7
- 230000014759 maintenance of location Effects 0.000 claims description 3
- SGPGESCZOCHFCL-UHFFFAOYSA-N Tilisolol hydrochloride Chemical compound [Cl-].C1=CC=C2C(=O)N(C)C=C(OCC(O)C[NH2+]C(C)(C)C)C2=C1 SGPGESCZOCHFCL-UHFFFAOYSA-N 0.000 claims 1
- 230000000694 effects Effects 0.000 claims 1
- 230000003628 erosive effect Effects 0.000 abstract description 9
- 238000000034 method Methods 0.000 abstract 1
- 238000005553 drilling Methods 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 238000005755 formation reaction Methods 0.000 description 5
- 239000004519 grease Substances 0.000 description 3
- 239000012530 fluid Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000002028 premature Effects 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000005552 hardfacing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000384 rearing effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B10/00—Drill bits
- E21B10/46—Drill bits characterised by wear resisting parts, e.g. diamond inserts
- E21B10/50—Drill bits characterised by wear resisting parts, e.g. diamond inserts the bit being of roller type
- E21B10/52—Drill bits characterised by wear resisting parts, e.g. diamond inserts the bit being of roller type with chisel- or button-type inserts
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B10/00—Drill bits
- E21B10/46—Drill bits characterised by wear resisting parts, e.g. diamond inserts
- E21B10/50—Drill bits characterised by wear resisting parts, e.g. diamond inserts the bit being of roller type
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Earth Drilling (AREA)
Abstract
A method to protect the exposed surface 20 formed by each of the legs of a rotary cone rock bit from erosion and abrasion includes a multiplicity of domed polycrystalline diamond inserts 48 to protect the lubricant reservoir system 30, the ball hole plug 50 and the shirt tail portion 22 of a sealed bearing bit. The diamond inserts are positioned upon the leading edge of the leg surface 21, the shirt tail portion 22 and the area surrounding the lubricant reservoir cover cap 38. Additionally, flush or domed tungsten carbide wear resistant inserts 49 may be incorporated for added protection of the leg. The wear resistant inserts may also be used upon the less vulnerable trailing edge 23 of the leg.
Description
lEG WEAR PROTECTION FOR ROWER CONE ROOC BlSlS BACKGROUND OF THE INVENTION 1. Field of the Invention
This invention relates to rotary cone rock bits utilized to bore holes in an earthen formation.
More particularly, this invention relates to protection of the rock bit legs for both sealed bearing rotary cone rock bits and openbearingrotary cone rock bit from erosion during rock bint drilling operations.
2. Background It is well-known that rotary cone rock bits (particularly sealed bearing rotary cone bits) are subjected to extremely harsh conditions during earth boring operations. Each rock bit is subjected to hard formations as well as the erosive effects of downhole hydraulics when the bits are run with drilling fluid. In addition, it is not uncommon for rotary cone rock bits to be subjected to drill string weights of up to 40,000 pounds.Additionally, the cuttings resulting from the borehole drilling operation have an extremely abrasive quay and contribute to the erosion of the various parts ofthe rotary cone rock bit.
Drill bit manufacturers have therefore expended considerable effort with limited success to protect the drill bit from this harsh environment.
U. S. Patent No. 3,130,801 utilizes a series of tungsten carbide inserts in the surface of the leg. The purpose of the inserts is to act as a reamer for the borehole to maintain the "gage" of the hole. The gage of the hole is the diameter of the hole as the bit works in the earthen formation.
Obviously, if the gage of the hole is allowed to become undersized, any new rock bit that follows a worn rock bit that has been removed from the drilktring will "pinch" as it is lowered or "tripped" back into the borehole, thereby causing premature failure of the new bit. This invention teaches using inserts near the "shirtaN' portion of each leg of the roller cone rock bit.
The ahirtil part of the leg is that portion of the leg nearest the borehole bottom and immediately adjacent the rotary cone rotatably secured to that particular leg
U. S. Patent No. 4,140,189, assigned to the same assignee as the present application and incorporated herein by reference, describes a sealed bearing rotary cone rock bit and a means to maintain gage of a borehole while the bit works in a borehole. A pair of cantilevered tungsten carbide inserts, with a diamond embedded in each cutting end of the inserts, extends well beyond the face of each leg of the roller cone rock bit.The primary purpose is to maintain gage of the borehole while providing little protection for the shirtail, leading edge and surrounding area adjacent the cover cap for the bit lubrication system of each leg of the bit.
U. S. Patent No. 4,591,008, also assigned to the same assignee ss the present application and incorporated herein by reference, describes a sealed bearing rotary cone rock bit and a means to protect the lubrication system incorporated in each leg of the roller cone rock bit. A multiplicity of flush-type tungsten carbide inserts are positioned in each leg of the rock bit surrounding the lubrication reservoir cover cap. The tungsten carbide flush inserts save to prevent erosion around the periphery of the cover cap thereby preventing a loss of the cover cap (hence a loss of lubricant to the roller cones). The cover cap protection thus prevents premature failure ofthe bit.
The present invention goes beyond the state of the art in that a means is provided to protect the entire leg from abrasion, erosion and corrosion. This protection includes the cover cap for the lubrication system, the ball hole plug and the shirtail, as well as a means to maintain gage of the borehole
SUMMARY OF THE INVENTION
It is an objet of this invention to provide a means to protect the legs of rotary cone rock bits from abrasive wear.
More specifically, it is an object of this invention to provide a multiplicity of semi-round diamond enhanced inserts strategically positioned along the leg surface from the lubricant cover cap to the shirtail of each leg to protect the leg from abrasive wear and to maintain the gage diameter of the borehole.
A rock bit body forms a first pin end and a second artting end One or more legs extend from the rock bit body. Each leg forms ajournal bearing that is cantilevered obliqudy toward an axis of the bit body. A rotary cutter cone is rotatively attached to the journal bearing. The lubrication system includes a lubricant reservoir chamber formed by each leg of the rock bit. The reservoir chamber is dosed out by a reservoir cover cap that is typically retained within an opening into the reservoir chamber formed by the leg ofthe rock bit.
A means is provided to protect the cover cap as well as the leg surface between the cover cap and the bottom of the shirtail. The cover cap protection means prevents the cover cap from becoming disengaged from the lubricant reservoir chamber through abrasion and erosion encountcred during drilling opcmions.
A multiplicity of diamond enhanced inserts are strategically positioned and interference 5toted within the leg surface of the rock bit The diamond enhanced inserts are positioned both adjacent to the reservoir cover cap and at least along a leading edge of each leg of the bit as well 'sadjacent to the outer edge of the shirtail.
A means to protect an exposed surface fonned by one or more legs of a three cone, sealed rearing, rock bit consists of a rock bit body having a first pin end and a second cutting end. Each of the three legs extend from the rock bit body. Each leg fonns a journal bering nearest the second cutdng end, having a rotary cone attached thereto.
A lubricant reservoir chamber is formed by each leg of the bit body. The reservoir chamber includes a reservoir cover cap that is retained within an opening to the reservoir chamber by a snap Ting, the snap ring bering retained in an annular groove formed in the leg adjacent the openig to the reservoir chamber.
A ball plug retainer is formed in a surface of each lek A shirtail portion is finned at the bottom of each leg adjacent each ofthe rotary cones. A leading edge and a trailing edge is formed by each leg between the reservoir chamber and the shirtail portion.
A means to protect the surface of each leg, the lubricant rcscrvóir chamber, the ball plug retainer and the shirtail portion consists of a multiplicity of diamond insets strategically positioned in the surface of each leg to prevent abrasion wear of each leg during operation ofthe bit in a borehole.
Each of the diamond enhanced inserts are preferably semi-round so that the inserts prouude from the surface of the rock bit leg thereby providing a means to cut the formation walls while the bit works in a borehole thus providing gage protection as well.
An advantage then of the present invention over the prior art is the use of diamond enhanced inserts strategically positioned along the surface of the legs of roller cone rock bits from the lubrication cover cap to the bottom of the shirtail thereby providing superior wear protection and borehole gage integrity for rotary cone rock bits.
Another advantage of the present invention over the prior art is the use of scmi-round diamond enhanced inserts along, and txtcnding from, the surface of the legs of roller cone rock bits thereby providing a means to cut the surface of the borehole walls thus assuring borehole gage integrity.
The above noted objects and advantages of the present invention will be more fuay understood upon a study of the fbllowing desssiption in conjunction with the detailed drawings.
BRIEF DESCRIPTION OF THE DRAWINGS HGURE 1 is a perspective view of a thee cone, sealed beading rock bit illustrating a series of diamond enhanced inserts positioned along a leading edge as well as around the lubrication cover cap and part way around the shirtail of each ofthe legs.
FIGURE 2 is a side elevational, partiany exploded view of one of the legs of the bit showing the cover cap and its snap ring retainer and the loon of each of the semi-round, diamond enhanced Inserts. Contional flush type tungsten carbide inserts are, for example, spaced from and positioned behind the diamond insats for added protection of the leg from abrasive wear.
FIGURE 3 is a partially broken away view taken through 3-3 of Fig. 2 illustrating the semi-round diamond enhanced inserts interference fitted within inset sockets formed in the surface of each leg.
DESCRIPTION OF ThE PREFERED EMBODIMENTS AND BEST MODE FOR CARRYING (YUT THE INVON Referring now to Figure 1, a sealed bearing rotary cone rock bit, generally designated as
10, consists of rock bit body 12. The bit body forms a threaded pin end 14 adapted to be
connected to a drill string at one end (not shown) and a cuting end generally desigatedas 16 at an opposite end. Thee cutter cones 17 comprise the cuting end 16. Each of the cones 17 are rotatively attached to legs 20 cxtendiiig from bit body 12.The cones 17 have, for example, a multiplicity of spaced tungsten carbide insats 18 interference fitted within insert sockets formed within each ofthe cones.
A grease reservoir system, generally designated as 30, comprises a grease cavity 32 (Fig.
2) formed in each of the legs 20 and a pressure compensating cover cap 38. A shirtail 22 is formed at the end of each ofthe legs 20 and is immediatcly adjacent each ofthe rotary cones 17.
Hydraulic "mud" (drilling fluid) is routed through a drillstring into pin end 14 and out through nozzles 26. The mud serves to lift rock chips and other detritus off the borehole bottom while, at the same time, cooling and cleaning the cutter cones 17 as they work in the borehole (not shown).
Figure 2 illustrates one of the legs 20 of the bit 10. The grease reservoir system 30 consists of a reservoir cavity 32, a resilient pressure compensating boot (not shown) and a cover cap 38. The cover cap 38 is retained within cavity 32 by, for example, snap ring 36. The snap ring 36 is retained within an annular'groove 34 fbnned in the wall of the cavity 32. When the cover cap 38 is assembled within the cavity 32, it is recessed within the leg 20. Thus, no part of the cover cap (or snap ring retention groove 34) extends beyond the surface of the leg 20.
As heretofore mentioned, without protection, the outer surface of the leg adjacent the cover cap can abrade away exposing the snap ring and groove. During extended drilling operations, the outer surface of the leg 20 will begin to wear away (even with tungsten carbide inserts imbedded in the surface in an area that includes the sluice adjacent the reservoir cavity 32. The abrasive and erosive effects of the earthen formation next to the bit will grind down the leg material both around the reservoir 30 and along the surface of the leg 20.Abrasive ww may occur to such an extent that the snap ring groove 34 becomes exposed. The resultant exposure could (and has) caused the section of both the snap ring 36 and the cover cap 38 from the reservoir system thus destroying the lubrication system vital to the continued operation of the bit in the borehole.
To protect the surface of the leg 20, cover cap 38, ball hole plug 50 and the shirtail , a series of diamond enhanced inserts, generally designated as 48, are strategically positioned in the surface ofthe leg 20.
The preferred diamond enhanced inserts 48 are the subject of U. S. Patent No. 4,604,106 and 4,811,801 assigned to the samt assignee as the present invention, both of which are incorporated herein by reference The transition layer polycrystalline diamond, semi-round inserts are manufactured by MEGADIAMOND, a division of SMITH INTERNATIONAL, INC. in
Provo Utah.
The diamond inserts 48 are positioned along the leading edge 21 of leg 20 and down around the end otthe leg or shirtail portion 22. The semi-round inserts thus protect the cover cap 38, the ball hole plug 50 and the shirtail of the leg 22 from abrasion and erosion. A series of backup tungsten carbide inserts 49 (either flush or domed tungsten carbide inserts may be utilized) may be positioned behind the diamond inserts 48 protecting the leading edge 21 of leg 20 for rdded protection of the leg. Either flush or domed tungsten carbide insets 49 may utilized as backup protection ofthe leg 20.
Figure 3 illustrates the diamond enhanced inserts 48 interference fitted within insert sockets S I formed in leg 20. The inserts 48 and 49 are typically pressed mto their retention sockets, However, the inserts may be metalurgically second within their sockets or, for that matter, bonded to the face of the leg 20 without departing from the intent ofthis invention.
Moreover, it would be obvious to strategically position the semi-round diamond enhanced inserts 48 and the backup tungsten carbide insets 49 a(jaccnt the less vulnerable trailing edge 23 of the leg without departing from the scope of this invention (not shown).
In addition, various types of hardfacing materials, well known in the arr, may be strategically metalurgically applied to the ice ofthe leg in cooperation with the inserts 48 and 49 fbr added protection for the rock bit 10 (also not shown).
It will of course be realized that various modifications can be made in the design and operation of the present invention without departing from the spirit thereof. Thw while the principal preferred construction and mode of opexaxion of the invention have becn explained in what is now considered to represent its best embodiments which have been illustrated and described, it should be understood that within the scope ofthe appended claims the invention may be pranced otherwise than as specifically illustrated and described.
Claims (15)
1. A means to protect an exposed surface formed by one or more legs of a rotary cone rock bit comprising: a rock it body having a first pin end and a second cutting end, one or more legs exend from the rock bit body, each leg having a journal bribing nearest the second cutting end, each ofthejournal bearings having a rotary cutter cone attached thereto,
said means to protect the legs is a multiplicity of strategically positioned diamond inserts seared to the surface fbrmed by said one or more legs, the diamond inserts serve to protect an exposed surface of the one or more legs from the abrasive effects present during operation of the bit in a borehole.
2. The invention as set fbrtb in claim 1 wherein the diamond insets are semi-round and extend from the surface of the one or more leg.
3. The invention as set firth in claim 2 wherein the semi-round diamond inserts serve to maintain a gage diameter ofthe borehole.
4. The invention as set fbrth in claim 3 wherein the semi-round diamond inserts are enhanced polycrystalline diamond inserts interference fined within insert sockets formed in the surface ofthe one or more legs.
5. The invention as set forth in claim 1 wherein the rotary cone rock bit is a sealed bearing rock bit having a lubrication system, said lubrication systsn consists of a lubrication reservoir chamber formed in said one or more legs, the reservoir chamber includes a cover cap that is retained by retention means within an opening to said chamber, means to protect the cover cap includes one or more diamond inserts strategically positioned around a leg surface adjacent the cover cap to protect the lubrication system from abrasive wear during operation of the bit in a borehole.
6. The irwell(jon as set forth in claim 5 wherein a leading edge formed by the one or more legs is protected by a plurality of diamond inserts in the leg surface that are positioned in a space relationship along the leading edge of each leg.
7. The invention as set forth in claim 6 wherein the diamond inserts are semi-round enhanced polycrystalline diamond insets interference fitted within sockets formed in the surface ofthe one or more legs.
8. The invention as set fith in claim 7 wherein the diamond inserts continue, in a spaced relationship, around the surface of the leg adjacent the shirtail portion thereby protecting the bottom of the one or more legs close to the rotary cones.
9. The invention as set forth in claim 8 wherein the diamond inserts protect a ball hole plug in each of the one or more legs of the rock bit.
10. The invention as set forth in claim 9 wherein the semi-round diamond inserts in the surface of each of the one or more legs serve to maintain the gage of the borehole during operation ofthe bit in the borehole.
11. The invention as set firth in claim 1 fUrther comprising a pluality of tungsten carbide inserts strategically positioned adjacent to the diamond insets for added protection of the surface ofthe one or more legs.
12. A means to protect an exposed surface formed by one or more legs of a three cone, sealed bearing rock bit comprisiag: a rock bit body having a first pin end and a second cutting end, each ofthe three legs exttnd from the rock bit body, each leg having a journal bearing nearest the second cutting end, each of the journal brings having a rotary cone attached thereto,
a lubricant reservoir chamer is formed by each leg of the bit body, the reservoir chamber includes a reservoir cover cap that is retained within an opening to the reservoir chamber by a snap ring, the snap ring bering retained in an annular groove formed in the leg adjacent the opening to the reservoir chamber,
a ball plug retainer formed in a surface of each leg,
a shirtail portion at the bottom of each leg adjacent each ofthe rotary cones, a leading edge and a trailing edge formed by each leg between the reservoir chamber and the silirtil portion, and
a means to protect the surface of each leg, the lubricant reservoir chamber, the ball plug retains and the shirtail portion, the means to protect the surface of each leg, the reservoir chamber, ball plug and the shirtail is a multiplicity of diamond insets strategically positioned in the surface of each leg to prevent abrasion wear of teach leg during operation ofthe bit in a borehole.
13. The invention as set forth in claim 12 wherein the diamond inserts are semi-round enhanced polycrystalline diamond inserts interfitted within sockets formed in the surface of each leg.
14. The invention as set forth in daim 12 further comprising a plurality of tungsten carbide insets strategically positioned adjacent the diamond inserts, the tungsten carbide insets serve to further protect the exposed surface formed by each leg of the staled bearing rotary cone rock bit
15. A means to protect an exposed surface formed by one or more legs
of a rotary cone rock bit substantially as herein described with reference to and as shown in the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US60455596A | 1996-02-21 | 1996-02-21 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9703368D0 GB9703368D0 (en) | 1997-04-09 |
| GB2310443A true GB2310443A (en) | 1997-08-27 |
Family
ID=24420076
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9703368A Withdrawn GB2310443A (en) | 1996-02-21 | 1997-02-18 | Leg wear protection for roller cone rock bits |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2198076A1 (en) |
| GB (1) | GB2310443A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2361258A (en) * | 2000-04-10 | 2001-10-17 | Smith International | Roller cone drill bit |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3130801A (en) * | 1961-02-09 | 1964-04-28 | Reed Roller Bit Co | Drill bit having inserts forming a reamer |
| US4140189A (en) * | 1977-06-06 | 1979-02-20 | Smith International, Inc. | Rock bit with diamond reamer to maintain gage |
| US4531595A (en) * | 1979-01-08 | 1985-07-30 | Housman Robert J | Wear resistant composite insert and boring tool with insert |
| US4591008A (en) * | 1984-08-22 | 1986-05-27 | Smith International, Inc. | Lube reservoir protection for rock bits |
| US5074367A (en) * | 1990-05-11 | 1991-12-24 | Rock Bit Industries, Inc. | Rock bit with improved shank protection |
| US5494123A (en) * | 1994-10-04 | 1996-02-27 | Smith International, Inc. | Drill bit with protruding insert stabilizers |
-
1997
- 1997-02-18 GB GB9703368A patent/GB2310443A/en not_active Withdrawn
- 1997-02-20 CA CA 2198076 patent/CA2198076A1/en not_active Abandoned
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3130801A (en) * | 1961-02-09 | 1964-04-28 | Reed Roller Bit Co | Drill bit having inserts forming a reamer |
| US4140189A (en) * | 1977-06-06 | 1979-02-20 | Smith International, Inc. | Rock bit with diamond reamer to maintain gage |
| US4531595A (en) * | 1979-01-08 | 1985-07-30 | Housman Robert J | Wear resistant composite insert and boring tool with insert |
| US4591008A (en) * | 1984-08-22 | 1986-05-27 | Smith International, Inc. | Lube reservoir protection for rock bits |
| US5074367A (en) * | 1990-05-11 | 1991-12-24 | Rock Bit Industries, Inc. | Rock bit with improved shank protection |
| US5494123A (en) * | 1994-10-04 | 1996-02-27 | Smith International, Inc. | Drill bit with protruding insert stabilizers |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2361258A (en) * | 2000-04-10 | 2001-10-17 | Smith International | Roller cone drill bit |
| US6439326B1 (en) | 2000-04-10 | 2002-08-27 | Smith International, Inc. | Centered-leg roller cone drill bit |
| GB2361258B (en) * | 2000-04-10 | 2002-12-24 | Smith International | Centered-leg roller cone drill bit |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9703368D0 (en) | 1997-04-09 |
| CA2198076A1 (en) | 1997-08-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |