CA1335988C - Drill bit with integrally forged stabilizer - Google Patents
Drill bit with integrally forged stabilizerInfo
- Publication number
- CA1335988C CA1335988C CA 562120 CA562120A CA1335988C CA 1335988 C CA1335988 C CA 1335988C CA 562120 CA562120 CA 562120 CA 562120 A CA562120 A CA 562120A CA 1335988 C CA1335988 C CA 1335988C
- Authority
- CA
- Canada
- Prior art keywords
- lug
- leg
- drill bit
- stabilizer
- body portion
- 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.)
- Expired - Fee Related
Links
- 239000003381 stabilizer Substances 0.000 title claims abstract description 27
- 238000005242 forging Methods 0.000 claims abstract description 11
- 229910003460 diamond Inorganic materials 0.000 claims abstract description 10
- 239000010432 diamond Substances 0.000 claims abstract description 10
- 238000005553 drilling Methods 0.000 claims abstract description 10
- 239000012530 fluid Substances 0.000 claims abstract description 7
- 210000003141 lower extremity Anatomy 0.000 claims description 5
- 230000002708 enhancing effect Effects 0.000 claims description 3
- 230000000087 stabilizing effect Effects 0.000 claims description 3
- 210000003414 extremity Anatomy 0.000 claims description 2
- 238000003754 machining Methods 0.000 claims 3
- 238000004519 manufacturing process Methods 0.000 claims 2
- 238000010276 construction Methods 0.000 description 8
- 230000008901 benefit Effects 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 238000005520 cutting process Methods 0.000 description 3
- 230000001965 increasing effect Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000005755 formation reaction Methods 0.000 description 2
- 239000011435 rock Substances 0.000 description 2
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 description 2
- 230000003628 erosive effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000003466 welding Methods 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
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/10—Wear protectors; Centralising devices, e.g. stabilisers
- E21B17/1092—Gauge section of drill bits
-
- 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
- E21B10/08—Roller bits
-
- 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
- E21B10/08—Roller bits
- E21B10/18—Roller bits characterised by conduits or nozzles for drilling fluids
-
- 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
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)
- Processing Of Stones Or Stones Resemblance Materials (AREA)
Abstract
The invention discloses a drill bit that is assembled from a plurality of machined forgings that are welded together to form a unitary structure. Each forging comprises an upper body portion and a lower leg portion. The lower leg portion is machined to form a shirttail section and a journal section, which in turn is adapted to rotatively support a cone shaped cutter.
In operation, the cutter is oriented to describe a circular path, the outer diameter of which forms the gage diameter of the bit.
The upper body portion is machined to include a stabilizer lug extending radially outward to substantially the same diameter as that formed by the cutters. The lower section of the lug cooperates with a recessed portion of the leg to form a flow passage for enabling drilling fluid to more easily pass upward through the borehole annulus during operation. A plurality of polycrystalline diamond inserts are mounted within the surface of each stabilizer lug.
In operation, the cutter is oriented to describe a circular path, the outer diameter of which forms the gage diameter of the bit.
The upper body portion is machined to include a stabilizer lug extending radially outward to substantially the same diameter as that formed by the cutters. The lower section of the lug cooperates with a recessed portion of the leg to form a flow passage for enabling drilling fluid to more easily pass upward through the borehole annulus during operation. A plurality of polycrystalline diamond inserts are mounted within the surface of each stabilizer lug.
Description
r~
:
~ DRI~T BIT WITH INTEGRA~LY ~ORGED STABI~IZER
BACgGROUND OF IHE l~v~lloN
4 l. FlelC o~ the ~nvention This invention relate6 to drill bits for drilling through 6 rock and other hard formations ln drilling oll wells, and more 7 psrticularly to rotary bits having depending legs with cutters 8 rotatably ~ounted on ~ournals extending lnwardly and downwardly 9 from the inner sides of the legs.
11 2. Description of t~e Prior Art ~2 Drilling bits of this type are con~entionally suspended from ~3 drill pipe extending downwardly from the drilling rig located at 9 the surface. Generally, the string of drill pipe is rotated by ~5 the drllling rig and this rotation is transmitted to the bit at l6 the bottom of the hole. In 60me cases, rotation of the bit is 7 accomplished through the use of a fluid motor mounted on the bot-18 tom of the drill string just above the bit. In either case, the 19 drill string, being of less diameter than the hole being drilled, 20 ls sub~ect to lateral whipping or other movement which creates a 21 certain amount of angularity to the string which is imparted, to 22 a certain degree, to the bit itself. This results ln a tilting 23 o~ the bit which causes ;xcesslve pressure of the lower leg por-24 tion6 of the blt against the formation as the bit is rotated.
25 This phenomenon is even more critical in directionPl drill~ng 26 where the bit is oriented at extreme angles from the vertical.
27 Because of physical constraint6 within the bore hole, bits were 28 originally constructed with relatively thin leg constructions.
29 AB a result, the rotating bit operated with an undue lateral 30 swinging or rocking motion which greatly reduced the operating _ 2 -~33~988 ~ life of the blt since the lower portion of the legs r~pidly wore 2 aw_y, le_ding to a se_l ~nd/or be_r~ng f ilure.
:
~ DRI~T BIT WITH INTEGRA~LY ~ORGED STABI~IZER
BACgGROUND OF IHE l~v~lloN
4 l. FlelC o~ the ~nvention This invention relate6 to drill bits for drilling through 6 rock and other hard formations ln drilling oll wells, and more 7 psrticularly to rotary bits having depending legs with cutters 8 rotatably ~ounted on ~ournals extending lnwardly and downwardly 9 from the inner sides of the legs.
11 2. Description of t~e Prior Art ~2 Drilling bits of this type are con~entionally suspended from ~3 drill pipe extending downwardly from the drilling rig located at 9 the surface. Generally, the string of drill pipe is rotated by ~5 the drllling rig and this rotation is transmitted to the bit at l6 the bottom of the hole. In 60me cases, rotation of the bit is 7 accomplished through the use of a fluid motor mounted on the bot-18 tom of the drill string just above the bit. In either case, the 19 drill string, being of less diameter than the hole being drilled, 20 ls sub~ect to lateral whipping or other movement which creates a 21 certain amount of angularity to the string which is imparted, to 22 a certain degree, to the bit itself. This results ln a tilting 23 o~ the bit which causes ;xcesslve pressure of the lower leg por-24 tion6 of the blt against the formation as the bit is rotated.
25 This phenomenon is even more critical in directionPl drill~ng 26 where the bit is oriented at extreme angles from the vertical.
27 Because of physical constraint6 within the bore hole, bits were 28 originally constructed with relatively thin leg constructions.
29 AB a result, the rotating bit operated with an undue lateral 30 swinging or rocking motion which greatly reduced the operating _ 2 -~33~988 ~ life of the blt since the lower portion of the legs r~pidly wore 2 aw_y, le_ding to a se_l ~nd/or be_r~ng f ilure.
3 Stabilizers for the drill string have been utilized hereto-4 fore but they were located _bove the drill bit ~ome dlstance away 5 from it, 60 that the bit 6till had an opportunity to move or tilt 6 laterally.
7 , 8 U.S. Patent No. 3,628,616 obviated some of these problems by g providing 6tabilizing means directly on the drill bit, thereby ~0 eliminating the need for additional subs and greatly reducing the 11 rocking motion of the bit. This 6tabilization me_ns consisted of 12 hard metal pads welded directly onto the upper portion of the bit body. These pads were of sufficient thickness to greatly g lengthen the l~fe of the bit while still keeping the upper bit 5 body dia~eter within the limits provided by the diametrical cut-16 ting path or bore described by the rotary cutters.
~7 In addition, this type of welded pad structure of necessity 18 had sharp corners which created stress risers on the leg. This, ~9 of course, i6 undesirable, since it greatly shortens the fatigue 20 life due to the ~chAn~cal notch created by welding in the ~ weaXe6t part of the leg.
23 Moreover, it was found that high flow rates of drilling flu-24 id during operation can erode the weld-on "plate" type pad right 25 ff' 26 Another shortcoming with the structure found in the '616 27 patent was that the lower portion of the lug with its straight 28 surface, formed a dam for hindering the upward flow of the dril-29 ling fluid through the borehole annulus. This in turn created 30 undue pressures and increased erosion on the lower leg portions 31 of the bit.
3~ ~ 3 I The type of bit described ln U.S. Patent No. 3,628,616 also 2 included a plurallty of tungsten carbide in6erts mounted on the 3 wear pad. However, these inserts have a t~ ncy to crack and 4 unduly wear during operation.
5 SUMMARY OF ~HE INv~l~ON `~
~ The present invention obv$ates the abo~e mentioned shortcom-8 ings, by providing stabilizing means lntegrally forged on the g drill blt body. This construction i8 achieved by having the 10 st~bilizing lugs pre-formed on the leg forgings. The lower sec-tion of each stabili2ing pad is rounded toward lts outer sldes ~2 and functions to cooperate with a recesseA portlon of the drill 13 bit body located beneath the lug- to create a flow channel away from the lower extremities of the blt body.
A primary advantage of this construction is that a metallur-16 gically solid bit body is formed that will resist breakage. In addition, being a forged part, the forged lugs galn a substanial ~8 increase in toughness and reliability through improvement of 19 grain 6tructure in the metal. With this design, the fibrous met-20 al grain is lined up parallel to the most severe stresses and 21 shoc~ loads that will be imposed on the leg. By taking advantage 22 of metal flow during the forging process, r~Y~u~ ~e^h~lcal 23 properties are obtained at the critically stressed sectlons.
Such a construction can also be conformed optimally to offer 26 good stabilization w~ile enhancing fluid flow and cutting remov~l 27 created by the flow channel construction.
28 Another advantage of the present invent$on is that the 29 forged cons'ruction provides a readily machinable boss that can 30 be turned to any diameter and reguire less operations than weld-31 on legs.
~2 - 4 -13359~8 1 The present lnvention also utillzes polycrystalline ~a~nd 2 compacts pressed into the stabilizer lugs to r-Y~ze wea~ The 3 insert configuration can either be flat or rounded and be flush 4 with the lug surface or extend beyond it. The advantage of the 5 rounded inserts extending beyond the luq is that the annular 6 space available for cuttings to ~low by i5 increased. This con-_ struction also provides secondary gage cutting to help maintain 8 bore hole diameter. Moreover, less torgue is generated due to .
g the reduction of surface area in contact wlth the hole wall.
BRIEF DESCRIPTION OF THE DRAWINGS
I
~2 Figure l is a perspective view of the drill bit in accor-dance with the present invention;
~4 Figure 2 is an enlarged ~ectional view on one of the legs of ~5 the drill bit taken along lines 3-3 of Figure l;
Figure 3 is a sectional view of the forging utilized to form, 28 the leg;
~9 Figure 4 is an enlarged side view of the leg;
21 Figure 5 i6 an enlarged fragmentary view of the stabilizer 22 lug in accordance with the present invention; and 23 Figure 6 is an enlarg?ed fragmentary vlew of a second embodi-24 ment of the stabilizer lug of the present invention.
2~
27 PR~k~ EMBODIMENT
28 Figure l illustrates a drill bit lO having a body 12 and a 29 threaded pin portion 14 which is adapted to be threadably con-. .
30 nected to the lower end of a drili string. Extending downwardly 3~ from the bit body 12 are legs 16. As shown in Figure 2, each leg ~S ~
1 16 has an inwardly and downwardly directed journal 18 which is 2 adapted to rotatably support a cutter illustrated at 20 in Figure 3 2 by broken lines. The cutters 20 are oriented to describe a 4 circular path, the outer diameter of which forms the gage diameter of the bit.
6 The base of the journal 18 is defined by a surface of revol-7 ution 22 lying in a plane normal to the longitudinal axis of the 8 journal 18. The surface of revolution 22 and the lower end of the 9 leg 16 define a relatively thin tapering bottom leg portion commonly known as a shirttail 24. The radial extremity of the 11 shirttail 24 does not extend out to the outer diameter of the bit 12 10 but has a clearance with the sidewalls of the bore hole.
13 Stabilizer lugs 30 are formed on the upper portion of each leg 14 16 extending radially outwardly to substantially the gage diameter of the bit 10. Figure 3 illustrates a forging 40 of one of the 16 legs 16. The forging 40 comprises a dome section 41, a journal 17 section 42, a shirttail section 43 and a stabilizer section 44.
18 The journal section 42 is machined to form the journal 18 and 19 the surface of revolution 22 as shown in Figure 2. The shirttail section 43 is also machined to remove some parent metal, shown in 21 broken lines, of the forging 40 to form the shirttail 24. This is 22 more clearly shown in Figure 4.
23 The forging 40 is also turned to machine away a portion of the 24 stabilizer section 44, shown in broken lines, to form the stabi-lizer pad 30. Three such leg forgings are welded together to form 26 the rock bit.
27 As shown in Figure 1, the lower portion of each stabilizer pad 28 30 forms a rounded portion 51 which curves upwardly to join with 29 the sides 53 of the lug 30. This rounded portion 51 cooperates with a recessed portion 55 formed on the leg 16 to form a ~ 33~988 1 flow ch~nnQ~ to enhance the flow of drilling fluld from around 2 the shlrttall 24 upwardly around the stabilizer lug30.
3 Drilling fluid (not ~llustrAted) enters the bore hole via a 4 plurality of nozzles 60 extending through the bit body 12.
6 Referring again to Figures 1 and 2, a lubricating system i8 _ al~o illustrated having a reservoir 61 having a pressure 8 equalizer 62 located therein. The one side of the egualizer com-g munic~tes with the outside of the bit through ports 63 formed in ~0 a cap 65. The other side of the egualizer 62 co~m~nlcates with 1~ the interior of the bearing chamber through pas6ages 66 and 6~.
12 Lubricant (not illustrated) completely fills the reservoir 61, l3 passages 66 and 67 and the bearing cavity.
4 Figure 4 more clearly illustrates a plurality of bores 45 ~5 for receiving a plurality of inserts 46. Each insert 46 is l6 preferably made of polycrystalline diamond and can have its outer 1~ surface 47 substantially flat in order to be flush with the outer 18 surface of the stabilizer lug 30. (See ~igure 5).
Alternatively, each insert 46 can also have rounded outer 21 pro~ections 48 extending beyond the outer surface of the 22 stabilizAr lug 30. (See Figure 6).
23 In addition, each ipsert 46 may be comprised entirely of 24 polycrystalline diamond, or else it may comprise of a wafer 25 brazed to a root portion made of tungsten carbide.
27 In operation, it has been found that integrally for2ed 28 stabilizer lug~ 30 have obviated many of the shortcomings found 29 in the prior art constructions. In addition, tpe diamond inserts 30 46 have greatly reduced wear on the stabilizer lug, thereby great-31 ly increasing the useful life of the drill bit.
1 It should be understood that changes can be made in the ex-2 act form, details and proportions of the construction without 3 departing from the spirit of the invention.
1~
~3 ~~~ ---14 .. ~5 lG
~4 ~25 .. . .
... . 29
~7 In addition, this type of welded pad structure of necessity 18 had sharp corners which created stress risers on the leg. This, ~9 of course, i6 undesirable, since it greatly shortens the fatigue 20 life due to the ~chAn~cal notch created by welding in the ~ weaXe6t part of the leg.
23 Moreover, it was found that high flow rates of drilling flu-24 id during operation can erode the weld-on "plate" type pad right 25 ff' 26 Another shortcoming with the structure found in the '616 27 patent was that the lower portion of the lug with its straight 28 surface, formed a dam for hindering the upward flow of the dril-29 ling fluid through the borehole annulus. This in turn created 30 undue pressures and increased erosion on the lower leg portions 31 of the bit.
3~ ~ 3 I The type of bit described ln U.S. Patent No. 3,628,616 also 2 included a plurallty of tungsten carbide in6erts mounted on the 3 wear pad. However, these inserts have a t~ ncy to crack and 4 unduly wear during operation.
5 SUMMARY OF ~HE INv~l~ON `~
~ The present invention obv$ates the abo~e mentioned shortcom-8 ings, by providing stabilizing means lntegrally forged on the g drill blt body. This construction i8 achieved by having the 10 st~bilizing lugs pre-formed on the leg forgings. The lower sec-tion of each stabili2ing pad is rounded toward lts outer sldes ~2 and functions to cooperate with a recesseA portlon of the drill 13 bit body located beneath the lug- to create a flow channel away from the lower extremities of the blt body.
A primary advantage of this construction is that a metallur-16 gically solid bit body is formed that will resist breakage. In addition, being a forged part, the forged lugs galn a substanial ~8 increase in toughness and reliability through improvement of 19 grain 6tructure in the metal. With this design, the fibrous met-20 al grain is lined up parallel to the most severe stresses and 21 shoc~ loads that will be imposed on the leg. By taking advantage 22 of metal flow during the forging process, r~Y~u~ ~e^h~lcal 23 properties are obtained at the critically stressed sectlons.
Such a construction can also be conformed optimally to offer 26 good stabilization w~ile enhancing fluid flow and cutting remov~l 27 created by the flow channel construction.
28 Another advantage of the present invent$on is that the 29 forged cons'ruction provides a readily machinable boss that can 30 be turned to any diameter and reguire less operations than weld-31 on legs.
~2 - 4 -13359~8 1 The present lnvention also utillzes polycrystalline ~a~nd 2 compacts pressed into the stabilizer lugs to r-Y~ze wea~ The 3 insert configuration can either be flat or rounded and be flush 4 with the lug surface or extend beyond it. The advantage of the 5 rounded inserts extending beyond the luq is that the annular 6 space available for cuttings to ~low by i5 increased. This con-_ struction also provides secondary gage cutting to help maintain 8 bore hole diameter. Moreover, less torgue is generated due to .
g the reduction of surface area in contact wlth the hole wall.
BRIEF DESCRIPTION OF THE DRAWINGS
I
~2 Figure l is a perspective view of the drill bit in accor-dance with the present invention;
~4 Figure 2 is an enlarged ~ectional view on one of the legs of ~5 the drill bit taken along lines 3-3 of Figure l;
Figure 3 is a sectional view of the forging utilized to form, 28 the leg;
~9 Figure 4 is an enlarged side view of the leg;
21 Figure 5 i6 an enlarged fragmentary view of the stabilizer 22 lug in accordance with the present invention; and 23 Figure 6 is an enlarg?ed fragmentary vlew of a second embodi-24 ment of the stabilizer lug of the present invention.
2~
27 PR~k~ EMBODIMENT
28 Figure l illustrates a drill bit lO having a body 12 and a 29 threaded pin portion 14 which is adapted to be threadably con-. .
30 nected to the lower end of a drili string. Extending downwardly 3~ from the bit body 12 are legs 16. As shown in Figure 2, each leg ~S ~
1 16 has an inwardly and downwardly directed journal 18 which is 2 adapted to rotatably support a cutter illustrated at 20 in Figure 3 2 by broken lines. The cutters 20 are oriented to describe a 4 circular path, the outer diameter of which forms the gage diameter of the bit.
6 The base of the journal 18 is defined by a surface of revol-7 ution 22 lying in a plane normal to the longitudinal axis of the 8 journal 18. The surface of revolution 22 and the lower end of the 9 leg 16 define a relatively thin tapering bottom leg portion commonly known as a shirttail 24. The radial extremity of the 11 shirttail 24 does not extend out to the outer diameter of the bit 12 10 but has a clearance with the sidewalls of the bore hole.
13 Stabilizer lugs 30 are formed on the upper portion of each leg 14 16 extending radially outwardly to substantially the gage diameter of the bit 10. Figure 3 illustrates a forging 40 of one of the 16 legs 16. The forging 40 comprises a dome section 41, a journal 17 section 42, a shirttail section 43 and a stabilizer section 44.
18 The journal section 42 is machined to form the journal 18 and 19 the surface of revolution 22 as shown in Figure 2. The shirttail section 43 is also machined to remove some parent metal, shown in 21 broken lines, of the forging 40 to form the shirttail 24. This is 22 more clearly shown in Figure 4.
23 The forging 40 is also turned to machine away a portion of the 24 stabilizer section 44, shown in broken lines, to form the stabi-lizer pad 30. Three such leg forgings are welded together to form 26 the rock bit.
27 As shown in Figure 1, the lower portion of each stabilizer pad 28 30 forms a rounded portion 51 which curves upwardly to join with 29 the sides 53 of the lug 30. This rounded portion 51 cooperates with a recessed portion 55 formed on the leg 16 to form a ~ 33~988 1 flow ch~nnQ~ to enhance the flow of drilling fluld from around 2 the shlrttall 24 upwardly around the stabilizer lug30.
3 Drilling fluid (not ~llustrAted) enters the bore hole via a 4 plurality of nozzles 60 extending through the bit body 12.
6 Referring again to Figures 1 and 2, a lubricating system i8 _ al~o illustrated having a reservoir 61 having a pressure 8 equalizer 62 located therein. The one side of the egualizer com-g munic~tes with the outside of the bit through ports 63 formed in ~0 a cap 65. The other side of the egualizer 62 co~m~nlcates with 1~ the interior of the bearing chamber through pas6ages 66 and 6~.
12 Lubricant (not illustrated) completely fills the reservoir 61, l3 passages 66 and 67 and the bearing cavity.
4 Figure 4 more clearly illustrates a plurality of bores 45 ~5 for receiving a plurality of inserts 46. Each insert 46 is l6 preferably made of polycrystalline diamond and can have its outer 1~ surface 47 substantially flat in order to be flush with the outer 18 surface of the stabilizer lug 30. (See ~igure 5).
Alternatively, each insert 46 can also have rounded outer 21 pro~ections 48 extending beyond the outer surface of the 22 stabilizAr lug 30. (See Figure 6).
23 In addition, each ipsert 46 may be comprised entirely of 24 polycrystalline diamond, or else it may comprise of a wafer 25 brazed to a root portion made of tungsten carbide.
27 In operation, it has been found that integrally for2ed 28 stabilizer lug~ 30 have obviated many of the shortcomings found 29 in the prior art constructions. In addition, tpe diamond inserts 30 46 have greatly reduced wear on the stabilizer lug, thereby great-31 ly increasing the useful life of the drill bit.
1 It should be understood that changes can be made in the ex-2 act form, details and proportions of the construction without 3 departing from the spirit of the invention.
1~
~3 ~~~ ---14 .. ~5 lG
~4 ~25 .. . .
... . 29
Claims (9)
1. A drill bit comprising:
a drill bit body having a main body portion rotatable about an axis and a plurality of legs extending downwardly therefrom with the lower end of each leg forming a relatively thin tapering extremity commonly known as a shirttail portion, each leg also having a journal extending downwardly and radially inwardly substantially toward the axis;
a cutter rotatably mounted on the journal of each leg, the cutter, upon rotation of the bit body, defining a circular path of cut extending radially outward a greater extent than the main body portion with the outer diameter forming the outer diameter or gauge of the drill bit; and a stabilizer lug integrally forged on the main body portion directly above each leg, each lug extending radially outward from the main body portion to substan-tially the same diameter as the circular path of cut, each lug having a smooth transitional surface between its lower extremity and the adjoining leg to avoid any stress risers therebetween, the lower extremity surface of each lug having smooth curved surfaces forming the lower corners of each lug to form a flow channel for enhancing fluid flow from around each shirttail portion upwardly around each stabilizer lug.
a drill bit body having a main body portion rotatable about an axis and a plurality of legs extending downwardly therefrom with the lower end of each leg forming a relatively thin tapering extremity commonly known as a shirttail portion, each leg also having a journal extending downwardly and radially inwardly substantially toward the axis;
a cutter rotatably mounted on the journal of each leg, the cutter, upon rotation of the bit body, defining a circular path of cut extending radially outward a greater extent than the main body portion with the outer diameter forming the outer diameter or gauge of the drill bit; and a stabilizer lug integrally forged on the main body portion directly above each leg, each lug extending radially outward from the main body portion to substan-tially the same diameter as the circular path of cut, each lug having a smooth transitional surface between its lower extremity and the adjoining leg to avoid any stress risers therebetween, the lower extremity surface of each lug having smooth curved surfaces forming the lower corners of each lug to form a flow channel for enhancing fluid flow from around each shirttail portion upwardly around each stabilizer lug.
2. The drill bit of claim 1 wherein said flow channel is further characterized by a radially recessed portion formed on the main body directly below each stabi-lizer lug.
3. The drill bit of claim 1 further characterized by a plurality of polycrystalline diamond inserts mounted within the surface of each stabilizer lug.
4. The drill bit of claim 1 further characterized by a plurality of polycrystalline diamond inserts mounted within the surface of each stabilizer lug.
5. The drill bit of claim 2 further characterized by a plurality of polycrystalline diamond inserts mounted within the surface of each stabilizer lug.
6. The drill bit of claim 3, 4 or 5 wherein each polycrystalline diamond insert is characterized by a flat bearing surface substantially co-extensive to the surface of the stabilizing lug.
7. The invention of claim 3, 4 or 5 wherein each polycrystalline diamond insert is characterized by a rounded bearing surface extending beyond the surface of the stabilizer lug.
8. A method of manufacturing a rotary drill bit comprising the steps of:
forging a plurality of individual leg elements for assembly along longitudinal surfaces, such an assembly of individual leg elements forming a rotary drill bit, each leg element having an upper body portion and a lower leg portion, the lower leg portions each including a journal supporting a drilling cutter rotatably mounted thereon for defining a circular path of cut extending radially outward a greater extent than the body portion of the drill bit with the outer diameter forming the outer diameter or gauge of the drill bit;
machining each leg element to form a shirttail portion on the upper body portion directly above the leg portion;
machining each leg element to form a stabilizer lug integral with the upper body portion directly above the leg portion, the stabilizer lug having a smooth transi-tional surface between its lower extremity and the adjoin-ing shirttail portion of the leg to avoid any stress risers therebetween, the lower extremity surface of the lug having smooth curved surfaces forming the lower corners of the lug to form a flow channel for enhancing fluid flow from around the shirttail portion upwardly around the stabilizer lug;
machining each leg element to form a journal extending downwardly and radially inwardly;
rotatably mounting a cutter on each journal; and orienting and securing the leg elements into a unitary structure comprising a drill bit body having a plurality of legs with cutters thereon extending downwardly from the bit body, the cutters on the legs collectively having an outer extent defining an outer diameter of the rotary drill bit, and the stabilizer lugs extending radially outwardly to substantially the same diameter as the cutter extensions.
forging a plurality of individual leg elements for assembly along longitudinal surfaces, such an assembly of individual leg elements forming a rotary drill bit, each leg element having an upper body portion and a lower leg portion, the lower leg portions each including a journal supporting a drilling cutter rotatably mounted thereon for defining a circular path of cut extending radially outward a greater extent than the body portion of the drill bit with the outer diameter forming the outer diameter or gauge of the drill bit;
machining each leg element to form a shirttail portion on the upper body portion directly above the leg portion;
machining each leg element to form a stabilizer lug integral with the upper body portion directly above the leg portion, the stabilizer lug having a smooth transi-tional surface between its lower extremity and the adjoin-ing shirttail portion of the leg to avoid any stress risers therebetween, the lower extremity surface of the lug having smooth curved surfaces forming the lower corners of the lug to form a flow channel for enhancing fluid flow from around the shirttail portion upwardly around the stabilizer lug;
machining each leg element to form a journal extending downwardly and radially inwardly;
rotatably mounting a cutter on each journal; and orienting and securing the leg elements into a unitary structure comprising a drill bit body having a plurality of legs with cutters thereon extending downwardly from the bit body, the cutters on the legs collectively having an outer extent defining an outer diameter of the rotary drill bit, and the stabilizer lugs extending radially outwardly to substantially the same diameter as the cutter extensions.
9. The method of manufacturing the rotary drill bit of claim 8 further characterized by the steps of:
drilling a plurality of bores into the surface of each stabilizing lug; and providing a polycrystalline diamond insert in each bore.
drilling a plurality of bores into the surface of each stabilizing lug; and providing a polycrystalline diamond insert in each bore.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US3662587A | 1987-04-10 | 1987-04-10 | |
| US036,625 | 1987-04-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1335988C true CA1335988C (en) | 1995-06-20 |
Family
ID=21889672
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 562120 Expired - Fee Related CA1335988C (en) | 1987-04-10 | 1988-03-22 | Drill bit with integrally forged stabilizer |
Country Status (7)
| Country | Link |
|---|---|
| BE (1) | BE1002144A5 (en) |
| CA (1) | CA1335988C (en) |
| DE (1) | DE3811370A1 (en) |
| FR (1) | FR2613764B3 (en) |
| GB (1) | GB2203470B (en) |
| MX (1) | MX167812B (en) |
| NL (1) | NL8800897A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5494123A (en) * | 1994-10-04 | 1996-02-27 | Smith International, Inc. | Drill bit with protruding insert stabilizers |
| US5755299A (en) * | 1995-08-03 | 1998-05-26 | Dresser Industries, Inc. | Hardfacing with coated diamond particles |
| US9574405B2 (en) | 2005-09-21 | 2017-02-21 | Smith International, Inc. | Hybrid disc bit with optimized PDC cutter placement |
| US8955413B2 (en) | 2009-07-31 | 2015-02-17 | Smith International, Inc. | Manufacturing methods for high shear roller cone bits |
| US8672060B2 (en) | 2009-07-31 | 2014-03-18 | Smith International, Inc. | High shear roller cone drill bits |
| RU2725712C1 (en) * | 2019-07-22 | 2020-07-03 | Дмитрий Юрьевич Сериков | Calibrator |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3628616A (en) * | 1969-12-18 | 1971-12-21 | Smith International | Drilling bit with integral stabilizer |
| US4068731A (en) * | 1976-11-17 | 1978-01-17 | Smith International, Inc. | Extended nozzle and bit stabilizer and method of producing |
| US4140189A (en) * | 1977-06-06 | 1979-02-20 | Smith International, Inc. | Rock bit with diamond reamer to maintain gage |
| DE2934471A1 (en) * | 1979-08-25 | 1981-03-26 | Smith International, Inc. (n.d. Ges. d. Staates Delaware), Newport Beach, Calif. | Rock drill for geothermal shafts - where cutters contain peripheral row of very hard tungsten carbide inserts to improve drill life in arduous working conditions |
| US4727943A (en) * | 1987-01-15 | 1988-03-01 | Wood Roy W | Rotary drill bit |
-
1988
- 1988-03-22 CA CA 562120 patent/CA1335988C/en not_active Expired - Fee Related
- 1988-04-05 DE DE19883811370 patent/DE3811370A1/en not_active Withdrawn
- 1988-04-07 NL NL8800897A patent/NL8800897A/en not_active Application Discontinuation
- 1988-04-08 MX MX1105188A patent/MX167812B/en unknown
- 1988-04-08 FR FR8804716A patent/FR2613764B3/en not_active Expired
- 1988-04-08 BE BE8800399A patent/BE1002144A5/en not_active IP Right Cessation
- 1988-04-11 GB GB8808453A patent/GB2203470B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| GB8808453D0 (en) | 1988-05-11 |
| FR2613764A1 (en) | 1988-10-14 |
| MX167812B (en) | 1993-04-13 |
| GB2203470B (en) | 1991-09-18 |
| DE3811370A1 (en) | 1988-10-27 |
| FR2613764B3 (en) | 1989-10-27 |
| BE1002144A5 (en) | 1990-07-31 |
| GB2203470A (en) | 1988-10-19 |
| NL8800897A (en) | 1988-11-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |