CA1218355A - Tooth design using cylindrical diamond cutting elements - Google Patents
Tooth design using cylindrical diamond cutting elementsInfo
- Publication number
- CA1218355A CA1218355A CA000450039A CA450039A CA1218355A CA 1218355 A CA1218355 A CA 1218355A CA 000450039 A CA000450039 A CA 000450039A CA 450039 A CA450039 A CA 450039A CA 1218355 A CA1218355 A CA 1218355A
- Authority
- CA
- Canada
- Prior art keywords
- bit
- cutting
- cutting elements
- face
- matrix
- 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
Links
- 238000005520 cutting process Methods 0.000 title claims abstract description 99
- 239000010432 diamond Substances 0.000 title claims abstract description 88
- 229910003460 diamond Inorganic materials 0.000 title claims abstract description 62
- 239000011159 matrix material Substances 0.000 claims description 45
- 230000015572 biosynthetic process Effects 0.000 claims description 16
- 239000012530 fluid Substances 0.000 abstract description 9
- 238000004140 cleaning Methods 0.000 abstract description 2
- 238000001816 cooling Methods 0.000 abstract description 2
- 206010048705 Paraneoplastic cerebellar degeneration Diseases 0.000 description 34
- 208000017787 Paraneoplastic neurologic syndrome Diseases 0.000 description 34
- 208000032307 premature centromere division Diseases 0.000 description 34
- 201000009266 primary ciliary dyskinesia Diseases 0.000 description 34
- 238000005553 drilling Methods 0.000 description 26
- 238000005755 formation reaction Methods 0.000 description 14
- 229910052751 metal Inorganic materials 0.000 description 12
- 239000002184 metal Substances 0.000 description 12
- 239000000463 material Substances 0.000 description 10
- 239000011435 rock Substances 0.000 description 8
- 238000000034 method Methods 0.000 description 7
- 230000008901 benefit Effects 0.000 description 4
- 238000003776 cleavage reaction Methods 0.000 description 4
- 230000007017 scission Effects 0.000 description 4
- 239000013078 crystal Substances 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000035515 penetration Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 238000005219 brazing Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000003208 petroleum Substances 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- NLZUEZXRPGMBCV-UHFFFAOYSA-N Butylhydroxytoluene Chemical compound CC1=CC(C(C)(C)C)=C(O)C(C(C)(C)C)=C1 NLZUEZXRPGMBCV-UHFFFAOYSA-N 0.000 description 1
- 241001052209 Cylinder Species 0.000 description 1
- 241000357437 Mola Species 0.000 description 1
- 101710186755 Putative pterin-4-alpha-carbinolamine dehydratase 1 Proteins 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003129 oil well Substances 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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
- E21B10/56—Button-type inserts
- E21B10/567—Button-type inserts with preformed cutting elements mounted on a distinct support, e.g. polycrystalline inserts
Abstract
IMPROVED TOOTH DESIGN USING CYLINDRICAL DIAMOND CUTTING ELEMENTS
Abstract of the Disclosure The cutting performance of cylindrical polycrystalline synthetic diamond elements is improved by segmenting such cylindrically shaped elements along a plane or planes parallel to the longitudinal axis of the cylindrically shaped elements. In the preferred embodiments half cylinder or quarter cylinder shaped segments are incorporated as the diamond cutting elements within teeth disposed on a rotating bit. The planar surface or surfaces characterizing the cylindrical segments are oriented within the tooth to provide the leading and cutting face of the diamond cutting element. Typically, such planar surfaces are entirely exposed and disposed adjacent to and form one wall of an adjacent and preceding fluid channel whereby cleaning and cooling efficiency is also improved.
page 1
Abstract of the Disclosure The cutting performance of cylindrical polycrystalline synthetic diamond elements is improved by segmenting such cylindrically shaped elements along a plane or planes parallel to the longitudinal axis of the cylindrically shaped elements. In the preferred embodiments half cylinder or quarter cylinder shaped segments are incorporated as the diamond cutting elements within teeth disposed on a rotating bit. The planar surface or surfaces characterizing the cylindrical segments are oriented within the tooth to provide the leading and cutting face of the diamond cutting element. Typically, such planar surfaces are entirely exposed and disposed adjacent to and form one wall of an adjacent and preceding fluid channel whereby cleaning and cooling efficiency is also improved.
page 1
Description
1 ¦ IMPROVED TOOTH DESIGN USING CYLIN~RICAL DIAMOND CUTTING ELEME~TS
3 ¦ Background of the Invention 5 i 6 ¦ 1. Field o~ the Invention 8 ¦ ~he present invention relates to the field of earth 9 1 boring tools and in particular to rotating bits incorporating 10 ¦ diamond elements.
12 ¦ 2. Description of the Prior Art 13 l 14 ¦ The use of diamonds in drilling products is well known.
15 ¦ ~ore recently synthetic diamonds both single crystal diamonds 16 ¦ (SCD) and polycrystalline diamonds (PCD~ have become commercially 17 ¦ available from various sources and have been used in such 18 1 products, with recognized advantages. For example, natural 19 ¦ diamond bits effect drilling with a plowing action in com~arison 20 ¦ to crushing in the case of a roller cone bit, whereas synthetic 21 ¦ diamonds tend to cut by a shearing action. In the case of rock 22 ¦ formations, for example, it is believed that less energy is 23 ¦ required to fail the rock in shear than in compression.
24 l More recently, a variety of synthetic diamond products 26 has become available commercially some of which are available as 27 ¦ polycrystalline ~roducts~ Crystalline diamonds preferentially page 2 ll ~ 33~5 1 fractures on (111), (110) and (100) planes whereas PCD tends to
3 ¦ Background of the Invention 5 i 6 ¦ 1. Field o~ the Invention 8 ¦ ~he present invention relates to the field of earth 9 1 boring tools and in particular to rotating bits incorporating 10 ¦ diamond elements.
12 ¦ 2. Description of the Prior Art 13 l 14 ¦ The use of diamonds in drilling products is well known.
15 ¦ ~ore recently synthetic diamonds both single crystal diamonds 16 ¦ (SCD) and polycrystalline diamonds (PCD~ have become commercially 17 ¦ available from various sources and have been used in such 18 1 products, with recognized advantages. For example, natural 19 ¦ diamond bits effect drilling with a plowing action in com~arison 20 ¦ to crushing in the case of a roller cone bit, whereas synthetic 21 ¦ diamonds tend to cut by a shearing action. In the case of rock 22 ¦ formations, for example, it is believed that less energy is 23 ¦ required to fail the rock in shear than in compression.
24 l More recently, a variety of synthetic diamond products 26 has become available commercially some of which are available as 27 ¦ polycrystalline ~roducts~ Crystalline diamonds preferentially page 2 ll ~ 33~5 1 fractures on (111), (110) and (100) planes whereas PCD tends to
2 be isotropic and exhibits this same cleavage but on a microscale
3 and therefore resists catastrophic large scale cleavage failure.
4 The result is a retained sharpness which appears to resist polishing and aids in cutting. Such products are described, for 6 e~ample, in U.S. Patents 3,913,2B0; 3,745,623; 3,816,085;
7 4,104,344 and 4,224,380.
9 In general, the PCD products are fabricated from syn~hetic and/or appropriately sized natural diamond crystals 11 under heat and pressuee and in the presence of â SOlVent/CâtalySt 12 to form the polycrystalline structure. In one form of product 13 the polycrystalline structures includes sintering aid material 14 distributed essentially in the interstices where adjacent crystals have not bonded together.
17 In another form, âS described for example in U. S.
18 Patents 3,745,623; 3,816,085; 3,913,280; 4,104,223 and 4,224,380 19 the resulting diamond sintered product is porous, porosity being achieved by dissolving out the nondiamond material or at least a 21 portion thereof, as disclosed for example, in U. S. 3,745,623;
22 4,104,344 and 4,224,380. For convenience, such a material may be 23 described as a porous PCD, as referenced in U.S. 4,224,380.
~4 Polycrystalline diamonds have been used in drilling 26 products either as individual compact elements or as relatively 2 thin PCD tables supported on a cemented tungsten carbide (WC) page 3 ll 1 ~2 1 ¦ support backings. In one form, the PCD compact is supported on a 2 ¦ cylindrical slug about 13.3 mm in diameter and about 3 mm long, 3 ¦ with a ~CD table of about 0.5 to 0.6 mm in cross section on the 4 ¦ face of the cut~er~ In another version, a stud cutter, the PCD
7 4,104,344 and 4,224,380.
9 In general, the PCD products are fabricated from syn~hetic and/or appropriately sized natural diamond crystals 11 under heat and pressuee and in the presence of â SOlVent/CâtalySt 12 to form the polycrystalline structure. In one form of product 13 the polycrystalline structures includes sintering aid material 14 distributed essentially in the interstices where adjacent crystals have not bonded together.
17 In another form, âS described for example in U. S.
18 Patents 3,745,623; 3,816,085; 3,913,280; 4,104,223 and 4,224,380 19 the resulting diamond sintered product is porous, porosity being achieved by dissolving out the nondiamond material or at least a 21 portion thereof, as disclosed for example, in U. S. 3,745,623;
22 4,104,344 and 4,224,380. For convenience, such a material may be 23 described as a porous PCD, as referenced in U.S. 4,224,380.
~4 Polycrystalline diamonds have been used in drilling 26 products either as individual compact elements or as relatively 2 thin PCD tables supported on a cemented tungsten carbide (WC) page 3 ll 1 ~2 1 ¦ support backings. In one form, the PCD compact is supported on a 2 ¦ cylindrical slug about 13.3 mm in diameter and about 3 mm long, 3 ¦ with a ~CD table of about 0.5 to 0.6 mm in cross section on the 4 ¦ face of the cut~er~ In another version, a stud cutter, the PCD
5 ¦ table also is supp~rted by a cylindrical substrate of tungsten
6 ¦ carbide of about 3 mm by 13.3 mm in diameter by 26mm in overall
7 ¦ length. These cylindrical PCD table faced cutters have been used
8 ¦ in drilling products intended to be used in soft to medium-hard
9 ¦ formations.
'' 10 l 11 ¦ Individual PCD elements of various geometrical shapes 12 ¦ have been used as substitutes for natural diamonds in certain 13 applications on drilling products. However, certain problems 14 arose with PCD elements used as indiviaual pieces of a given carat size or weight. In general, natural diamond, available in 16 a wide variety of shapes and grades, was placed in predefined 17 locations in a mola, and production of the tool was completed by 18 various conventional techniques. The result is the formation of 19 a metal carbide matrix which holds the diamond in place, this matrix sometimes being referred to as a crown, the latter 21 attached to a steel blank by a metallurgical and mechanical bond 22 formed during the process of forming the metal matrix. Natural 23 diamond is sufficiently thermally stable to withstand the heating 24 process in metal matrix formation.
26 In this procedure above described, the natural diamond 2 could be either surface-set in a predetermined orientation, or page 4 ~Z~L8~5 1 impregnated, i.e., diamond is distributed throughout the matrix 2 in grit or fine particle form.
4 With early PCD elements, problems arose in the produc~ion of drilling products because PCD elements especially 6 PCD tables on carbide backing tended to be thermally unstable at 7 the temperature used in the furnacing of the metal matrix bit 8 crown, resulting in catastrophic failure of the PCD elements if 9 the same procedures as were used with natural diamonds were used with them. It was believed that the catastrophic failure was due 11 to thermal stress cracks from the expansion of residual metal or 12 metal alloy used as the sintering aid in the formation of the PCD
13 element.
Brazing techniques were used to fix the cylindrical PCD
1 table faced cutter into the matrix using temperature unstable PCD
17 products. Brazing materials and procedures were used to assure 1 that temperatures were not reached which would cause catastrophic 1 failure of the PCD element during the manufacture of the drilling 2 tool. The re~ult was that sometimes the PCD components separated 21 from the metal matrix, thus adversely affecting performance of 22 the drilling tool.
2 With the advent of thermally stable PCD elements, 2 typically porous PCD material, it was believed that such elements 2 could be surface-set into the metal matrix much in the same 2 fashion as natural diamonds, thus simplifying the manufacturing page 5 33~
l process of the drill tOolr and providing better performance due 2 to the fact that PCD elements were believed to have advantages of 3 less tendency to polish, and lack of inherently weak cleavage 4 planes as compared to natural diamond.
6 Significantly, the current literature relating to porous 7 PCD compacts sugyests that the element be surface-set. The 8 porous PCD compacts, and those said to be temperature stable up to about 1200C are available in a variety of shapes, e.g., cylindrical and triangular. The triangular material typically is ll about 0.3 carats in weight, measures 4mm on a side and is about 12 2.6mm thick. It is suggested by the prior art that the 13 triangular porous PCD compact be surface-set on the face with a 14 minimal point exposure, i.e., less than 0.5mm above the adjacent metal matrix face for rock drills. Larger one per carat l6 synthetic triangular diamonds have also become available, 17 measuring 6 mm on a side and 3.7 mm thick, but no recommendation 18 has been made as to the degree of exposure for such a diamond.
ln the case of abrasive rock, it is suggested by the prior art that the triangular element be set completely below the metal 21 matrix~ For soft nonabrasive rock, it is suggested by the prior 22 art that the triangular element be set in a radial orientation 23 with the base at about the level of the metal matrix. The degree 24 of exposure recommended thus depended on the type of rock formation to be cut.
The difficulties with such placements are several~ The 8 page 6 ~Z~ 835~3 1 difficulties may be understood by considering the dynamics of the ~ drilling operation. In the usual drilling operation, be it 3 mining, coring, or oil well drilling, a fluid such as water, air 4 or drilling mud is pumped through the center of the tool, radially outwardly across ~he tool face, radially around the 6 outer surface (gage~ and then back up the bore. The drilling 7 fluid clears the tool face of cuttings and ~o some extent cools 8 the cutter face. Where there is insufficient clearance between 9 the formation cut and the bit body, the cuttings may not be cleared from the face, especially where the formation is soft or 11 brittle. Thus, if the clearance between the cutting 12 surface-formation interface and the tool body face is relatively 13 small and if no provision is made for chip clearance, there may 14 be bit clearing problems.
16 Other factors to be considered are the weight on the 17 drill bit, normally the weight of the drill string and 18 principall~ the weight of the drill collar, and the effect of the 19 fluid which tends to lift the bit off the bottom. It has been 2 reportedr for example, that the pressure beneath a diamond bit 21 may be as much as 1000 psi greater than the pressure above the 22 bit, resulting in a hydraulic lift, and in some cases the 23 hydraulic lift force exceeds 50~ of the applied load while 24 drilling.
26 One surprising observation made in drill bits having 27 surface-set thermally stable PCD elements is that even after page 7 1 sufficient ex~osure of the cutting face has been achieved, by 2 running the bit in the hole and after a fracion of the surface of 3 the metal matrix was abraded away, the rate of penetration often 4 decreases. Examination of the bit indicates unexpected polishing of the PCD elements. ~sually ROP can be increased by adding 6 weight to the drill string or replacing the bit. Adding weight 7 to the drill string is generally objectionable because it 8 increases stress and wear on the drill rig. Further, tripping or replacing the bit is expensive since the economics of drilling in normal cases are expressed in cost per foot of penetration. The 11 cost calculation takes into account the bit cost plus the rig 1 cost including trip time and drilling time divided by the footage 13 drilled.
Clearly, it is desirable to provide a drilling tool 16 having thermally stable PCD elements and which can be 17 manufactured at reasonable costs and which will perform well in 18 terms of length of bit life and rate of penetration.
., 2 It is also desirable to provide a drilling tool having 21 thermally stable PCD elements so located and positioned in the 22 face of the tool as to ~rovide cutting without a long run-in 23 period, and one which provides a sufficient clearance between the 24 cutting elements and the formation for effective flow of drilling fluid and for clearance of cuttings.
Run-in in diamond bits is required to break off the tip page 8 ~Z~83~S
1 or point o~ the triangular cutter before efficient cutting can 2 begin. The amount of tip loss is approximately equal to the 3 I total exposure of natural diamondsO Therefore, an extremely 4 large initial exposure is required for synthetic diamonds as compared to natural diamonds. Therefore, to accommodate expected 6 1 wearing during drilling, to allow for tip removal during run-in, 7 and to provide flow clearance necessary, substantial initial 8 ¦ clearance is needed~
9 l
'' 10 l 11 ¦ Individual PCD elements of various geometrical shapes 12 ¦ have been used as substitutes for natural diamonds in certain 13 applications on drilling products. However, certain problems 14 arose with PCD elements used as indiviaual pieces of a given carat size or weight. In general, natural diamond, available in 16 a wide variety of shapes and grades, was placed in predefined 17 locations in a mola, and production of the tool was completed by 18 various conventional techniques. The result is the formation of 19 a metal carbide matrix which holds the diamond in place, this matrix sometimes being referred to as a crown, the latter 21 attached to a steel blank by a metallurgical and mechanical bond 22 formed during the process of forming the metal matrix. Natural 23 diamond is sufficiently thermally stable to withstand the heating 24 process in metal matrix formation.
26 In this procedure above described, the natural diamond 2 could be either surface-set in a predetermined orientation, or page 4 ~Z~L8~5 1 impregnated, i.e., diamond is distributed throughout the matrix 2 in grit or fine particle form.
4 With early PCD elements, problems arose in the produc~ion of drilling products because PCD elements especially 6 PCD tables on carbide backing tended to be thermally unstable at 7 the temperature used in the furnacing of the metal matrix bit 8 crown, resulting in catastrophic failure of the PCD elements if 9 the same procedures as were used with natural diamonds were used with them. It was believed that the catastrophic failure was due 11 to thermal stress cracks from the expansion of residual metal or 12 metal alloy used as the sintering aid in the formation of the PCD
13 element.
Brazing techniques were used to fix the cylindrical PCD
1 table faced cutter into the matrix using temperature unstable PCD
17 products. Brazing materials and procedures were used to assure 1 that temperatures were not reached which would cause catastrophic 1 failure of the PCD element during the manufacture of the drilling 2 tool. The re~ult was that sometimes the PCD components separated 21 from the metal matrix, thus adversely affecting performance of 22 the drilling tool.
2 With the advent of thermally stable PCD elements, 2 typically porous PCD material, it was believed that such elements 2 could be surface-set into the metal matrix much in the same 2 fashion as natural diamonds, thus simplifying the manufacturing page 5 33~
l process of the drill tOolr and providing better performance due 2 to the fact that PCD elements were believed to have advantages of 3 less tendency to polish, and lack of inherently weak cleavage 4 planes as compared to natural diamond.
6 Significantly, the current literature relating to porous 7 PCD compacts sugyests that the element be surface-set. The 8 porous PCD compacts, and those said to be temperature stable up to about 1200C are available in a variety of shapes, e.g., cylindrical and triangular. The triangular material typically is ll about 0.3 carats in weight, measures 4mm on a side and is about 12 2.6mm thick. It is suggested by the prior art that the 13 triangular porous PCD compact be surface-set on the face with a 14 minimal point exposure, i.e., less than 0.5mm above the adjacent metal matrix face for rock drills. Larger one per carat l6 synthetic triangular diamonds have also become available, 17 measuring 6 mm on a side and 3.7 mm thick, but no recommendation 18 has been made as to the degree of exposure for such a diamond.
ln the case of abrasive rock, it is suggested by the prior art that the triangular element be set completely below the metal 21 matrix~ For soft nonabrasive rock, it is suggested by the prior 22 art that the triangular element be set in a radial orientation 23 with the base at about the level of the metal matrix. The degree 24 of exposure recommended thus depended on the type of rock formation to be cut.
The difficulties with such placements are several~ The 8 page 6 ~Z~ 835~3 1 difficulties may be understood by considering the dynamics of the ~ drilling operation. In the usual drilling operation, be it 3 mining, coring, or oil well drilling, a fluid such as water, air 4 or drilling mud is pumped through the center of the tool, radially outwardly across ~he tool face, radially around the 6 outer surface (gage~ and then back up the bore. The drilling 7 fluid clears the tool face of cuttings and ~o some extent cools 8 the cutter face. Where there is insufficient clearance between 9 the formation cut and the bit body, the cuttings may not be cleared from the face, especially where the formation is soft or 11 brittle. Thus, if the clearance between the cutting 12 surface-formation interface and the tool body face is relatively 13 small and if no provision is made for chip clearance, there may 14 be bit clearing problems.
16 Other factors to be considered are the weight on the 17 drill bit, normally the weight of the drill string and 18 principall~ the weight of the drill collar, and the effect of the 19 fluid which tends to lift the bit off the bottom. It has been 2 reportedr for example, that the pressure beneath a diamond bit 21 may be as much as 1000 psi greater than the pressure above the 22 bit, resulting in a hydraulic lift, and in some cases the 23 hydraulic lift force exceeds 50~ of the applied load while 24 drilling.
26 One surprising observation made in drill bits having 27 surface-set thermally stable PCD elements is that even after page 7 1 sufficient ex~osure of the cutting face has been achieved, by 2 running the bit in the hole and after a fracion of the surface of 3 the metal matrix was abraded away, the rate of penetration often 4 decreases. Examination of the bit indicates unexpected polishing of the PCD elements. ~sually ROP can be increased by adding 6 weight to the drill string or replacing the bit. Adding weight 7 to the drill string is generally objectionable because it 8 increases stress and wear on the drill rig. Further, tripping or replacing the bit is expensive since the economics of drilling in normal cases are expressed in cost per foot of penetration. The 11 cost calculation takes into account the bit cost plus the rig 1 cost including trip time and drilling time divided by the footage 13 drilled.
Clearly, it is desirable to provide a drilling tool 16 having thermally stable PCD elements and which can be 17 manufactured at reasonable costs and which will perform well in 18 terms of length of bit life and rate of penetration.
., 2 It is also desirable to provide a drilling tool having 21 thermally stable PCD elements so located and positioned in the 22 face of the tool as to ~rovide cutting without a long run-in 23 period, and one which provides a sufficient clearance between the 24 cutting elements and the formation for effective flow of drilling fluid and for clearance of cuttings.
Run-in in diamond bits is required to break off the tip page 8 ~Z~83~S
1 or point o~ the triangular cutter before efficient cutting can 2 begin. The amount of tip loss is approximately equal to the 3 I total exposure of natural diamondsO Therefore, an extremely 4 large initial exposure is required for synthetic diamonds as compared to natural diamonds. Therefore, to accommodate expected 6 1 wearing during drilling, to allow for tip removal during run-in, 7 and to provide flow clearance necessary, substantial initial 8 ¦ clearance is needed~
9 l
10 ¦ Still another advantage is the provision of a drilling
11 ¦ tool in which thermally stable PCD elements of a defined
12 ¦ predetermined geometry are so positioned and supported in a metal
13 matrix as to be effectively locked into the matrix in order to
14 ¦ provide reasonably long life of the tooling by preventing loss of PCD elements other than by normal wear.
16 l 17 It is also desirable to provide a drilling tool having 18 1 thermally stable PCD elements so affixed in the tool that it is 19 ¦ usable in specific formations without the necessity of 20 ¦ significantly increased drill string weight/ bit torque, or 21 ¦ significant increases in drilling fluid flow or pressure, and 22 ¦ which will drill at a higher ROP than conventional fits under the 23 ¦ same drilling conditions.
24 l Brief Summary of the Invention 27 ¦ The present invention is an improvement in a rotating 28 l page 9 3~S
bit having a bit face wherein the ,mprovement comprises a plurality of teeth disposed on the bit and wherein each tooth includes a diamond cutting element. The diamond cutting element is particularly characterized by having the shape of a segment of a cylinder. The segment includes at least one planar surface and the planar surface forms, at least in part, a leading surface of the tooth.
Thus in the broad aspect the present invention provides a rotating bit characterized by a longitudinal axis of rotation for use in earth boring comprising:
a matrix body member having portions forming a gage and a face, said face including a plurality of channels forming pad means between at least some of the adjacent channels, each said pad means including a plurality of spaced synthetic polycrystalline diamond cutting elements mounted directly in the matrix during matrix formation, each of said cutting elements being of a predetermined geometric shape and being temperature stable to at least about 1203 degrees C., the said cutting elements including a portion received within the matrix member of said pad means and a portion which extends above the surface of said pad means and which is adapted to form the cutting face of said cutting elemen~, each cutting element including a generally curved rear face and a cutting face, ~r~
page 10 ~
g~ZgL~3~5 at least some of said cutting elements having a longitudinal axis and being characterized in shape as a segment of a cylinder including at least one planar surface, said planar sur~ace forminy at least in part a leading surface of said cutting face, said longitudinal axis of said cutting element lying in a plane parallel to said longitudinal axis of rotation of said bit, and the portion of said cutting elements which forms the cutting face of said cutting elements extending more than 0.5 mm above the surface of the corresponding pad.
The cylindrical segment may be a split half cylinder or a split quarter cylinder. The diamond cutting element is characterized by having a longitudinal axis lying along the length of the cylinder and wherein the cylindrical shape is a half cylinder shape, the planar surface is a planar surface lying along a diameter of the cylindrical shape. In the case where the cylindrical segment is a quarter segment of a full cylinder, the quarter segment includes an apical edge which lies along the longitudinal axis of the cylinder. In each case, the apical edge of the quarter cylinder and the planar surface of the half cyl inder diamond cutting element serves as an exposed leading surface of the tooth and is disposed adjacent to a fluid channel thereby forming in whole or in part one edge or wall of the fluid channel. As a resul~ of these improvements a cutting tooth is proviaed using cylindrical elements characterized by improved cutting efficiency, cleaning and cooling efficiency, and less tendency to dull or polish than is the case with prior ar~
f ully cyl indr ical elements used in rotating bits.
page lOa 335~
1 ¦ The present invention and its various embodiments are 2 better understood by first considering the following drawings 3 wherein like elements are referenced by like numerals.
Brief ~escription of the Drawings 7 Figure l is a cross-sectional view of a tooth 8 incorporating a cylindrical diamond segment according to the ¦ ~resent invention.
10 l 11 ¦ Figure 2 is a plan view of three teeth of the type shown 12 in Figure l.
13 l 14 ¦ Figure 3 is a cross-sectional view through a rotating
16 l 17 It is also desirable to provide a drilling tool having 18 1 thermally stable PCD elements so affixed in the tool that it is 19 ¦ usable in specific formations without the necessity of 20 ¦ significantly increased drill string weight/ bit torque, or 21 ¦ significant increases in drilling fluid flow or pressure, and 22 ¦ which will drill at a higher ROP than conventional fits under the 23 ¦ same drilling conditions.
24 l Brief Summary of the Invention 27 ¦ The present invention is an improvement in a rotating 28 l page 9 3~S
bit having a bit face wherein the ,mprovement comprises a plurality of teeth disposed on the bit and wherein each tooth includes a diamond cutting element. The diamond cutting element is particularly characterized by having the shape of a segment of a cylinder. The segment includes at least one planar surface and the planar surface forms, at least in part, a leading surface of the tooth.
Thus in the broad aspect the present invention provides a rotating bit characterized by a longitudinal axis of rotation for use in earth boring comprising:
a matrix body member having portions forming a gage and a face, said face including a plurality of channels forming pad means between at least some of the adjacent channels, each said pad means including a plurality of spaced synthetic polycrystalline diamond cutting elements mounted directly in the matrix during matrix formation, each of said cutting elements being of a predetermined geometric shape and being temperature stable to at least about 1203 degrees C., the said cutting elements including a portion received within the matrix member of said pad means and a portion which extends above the surface of said pad means and which is adapted to form the cutting face of said cutting elemen~, each cutting element including a generally curved rear face and a cutting face, ~r~
page 10 ~
g~ZgL~3~5 at least some of said cutting elements having a longitudinal axis and being characterized in shape as a segment of a cylinder including at least one planar surface, said planar sur~ace forminy at least in part a leading surface of said cutting face, said longitudinal axis of said cutting element lying in a plane parallel to said longitudinal axis of rotation of said bit, and the portion of said cutting elements which forms the cutting face of said cutting elements extending more than 0.5 mm above the surface of the corresponding pad.
The cylindrical segment may be a split half cylinder or a split quarter cylinder. The diamond cutting element is characterized by having a longitudinal axis lying along the length of the cylinder and wherein the cylindrical shape is a half cylinder shape, the planar surface is a planar surface lying along a diameter of the cylindrical shape. In the case where the cylindrical segment is a quarter segment of a full cylinder, the quarter segment includes an apical edge which lies along the longitudinal axis of the cylinder. In each case, the apical edge of the quarter cylinder and the planar surface of the half cyl inder diamond cutting element serves as an exposed leading surface of the tooth and is disposed adjacent to a fluid channel thereby forming in whole or in part one edge or wall of the fluid channel. As a resul~ of these improvements a cutting tooth is proviaed using cylindrical elements characterized by improved cutting efficiency, cleaning and cooling efficiency, and less tendency to dull or polish than is the case with prior ar~
f ully cyl indr ical elements used in rotating bits.
page lOa 335~
1 ¦ The present invention and its various embodiments are 2 better understood by first considering the following drawings 3 wherein like elements are referenced by like numerals.
Brief ~escription of the Drawings 7 Figure l is a cross-sectional view of a tooth 8 incorporating a cylindrical diamond segment according to the ¦ ~resent invention.
10 l 11 ¦ Figure 2 is a plan view of three teeth of the type shown 12 in Figure l.
13 l 14 ¦ Figure 3 is a cross-sectional view through a rotating
15 ¦ bit sho~ing the area of a gage-to-shoulder transition
16 ¦ incorporating the teeth of Figure l.
17 I
18 ¦ Figure 4 is a plan view in reduced scale showing a
19 ¦ coring bit incorporating the teeth of Figures l and 2.
20 l
21 ¦ Figure S is a half profile view of the coring bit of
22 ¦ E'igure 4.
23 l
24 ¦ Figure 6 is a plan view of the gage-to-shoulder transition of the coring bit in Figure 4 in conformity with the 26 teaching of Figure 3.
page ll ~ 33~5 1 Figure 7 is a cross-sectional view in enlarged scale of 2 a tooth incorporating a second embodiment of the present 3 invention.
Figure 8 is a plan view of three teeth devised according 6 to the second embodiment shown in Figure 7.
8 The present invention and its various embodiments may be 9 better understood by viewing the above figures in light of ~he following detailed description.
12 Detailed Description of the Preferred Em~odiments 14 The present invention is an improvement in a tooth design used in rotating bits, particularly rotary bits, wherein 16 the tooth includes a diamond cutting element and in particular a diamond cutting element derived from cylindrical polycrystalline 18 synthetic diamond (PCD). Such full cylindrical elements are 19 generally commercially available but not in segment form. Such synthetic diamond is formed in the shape of a full circular 21 cylinder having one planar end perpendicular to the longitudinal 22 axis of the cylindrical shape and an opposing domed end, 23 generally formed in the shape of a circular cone. Such elements 24 are typically available in a variety of sizes with the above described shape.
227 According to the present invention, the full cylindrical page 12 3~5 1 ¦ diamond element is segmented to form a cylindrical segment 2 ¦ wherein the segment is then axially disposed within a bit tooth.
3 ¦ Such segmented or split cylindrical elements thus provide a 4 ¦ cutting element with improved cutting efficiency with less use of diamond material and less tendency to dull or polishG The 6 present invention and its various embodiments may be better 7 understood by now turning to Figure 1.
9 ~igure 1 is a cross-sectional view of a first embodiment of the present invention showing a tooth, generally denoted by 11 reference numeral 10, incorporating a diamond cutting element, 12 gener~lly denoted by reference numeral 12. Element 12 is axially 13 disposed within the tungsten-carbide matrix material 14 of the 14 rotating bit. ln other words, longitudinal axis 16 of element 12 is oriented to be approximately perpendicular to bit surface 18 16 at the location of tooth 10. Bit surface 18 may be bit face of a 17 crown of a rotating bit or may be the superior sur face of a 18 raised land or pad disposed upon a bit crown. In either case, 19 bit surface 18 is taken in the present description as the basal 2 surface upon which tooth 10 is disposed.
2 As better seen in Figure 2, element 12 is approximately 2 a quarter section or 90 degrees of the full cylindrical shape of 2 the PCD element normally available. Element 12 is cut using a 2 conven~ional laser cutter. For example, deep cuts are made every 26 ¦ 90 degrees parallel to the longitudinal axis 16 of a full 27 ¦ cylindrical diamond element. Although the laser could be used to 28 l page 13 Il ~L218355 1 completely cut through the diamond element, it has been found 2 ¦ possible that with deep ~coring, the diamond can then be 3 ¦ fractured with propagation of the fracture lying approximately 4 ¦ along the continuation of the plane of the laser cut. For S ¦ example, the laser may cut a millimeter or less into and along 6 ¦ the length of the full cylindrical diamond element.
7 ¦ diametrically opposed cut of equal depth is also provided on the 8 ¦ cylinder. Thereafter, the cylinder may be split in half and then 9 ¦ later quartered on another laser cut by fracturing the diamond 10 ¦ element using an impulsive force and chisel.
12 ¦ Diamond element 12 is disposed within tooth 10 as 13 ¦ isshown in Figure 2 so that the apical edge 20 of diamond 12 14 ¦ formed by the cleavage planes or laser cuts which have formed 15 ¦ radial surfaces 22, is oriented in the leading or forward 16 ¦ direction of tooth 10 as defined by the rotation of the bit upon 17 ¦ which tooth 10 is disposed.
18 l 19 ¦ Turning again ~o Figure 1, it can be seen ~hat a portion 20 ¦ of element 12 is fully exposed above bit surface 18 and in 21 ¦ particular, that apical edge 20 forms the foremost portion of 22 ¦ diamond element 12 as the tooth moves forwardly in the plane of 23 ¦ the figure. Surfaces 22 define a dihedral angle and the 24 ¦ tangential direction of movement of tooth 10 during normal
page ll ~ 33~5 1 Figure 7 is a cross-sectional view in enlarged scale of 2 a tooth incorporating a second embodiment of the present 3 invention.
Figure 8 is a plan view of three teeth devised according 6 to the second embodiment shown in Figure 7.
8 The present invention and its various embodiments may be 9 better understood by viewing the above figures in light of ~he following detailed description.
12 Detailed Description of the Preferred Em~odiments 14 The present invention is an improvement in a tooth design used in rotating bits, particularly rotary bits, wherein 16 the tooth includes a diamond cutting element and in particular a diamond cutting element derived from cylindrical polycrystalline 18 synthetic diamond (PCD). Such full cylindrical elements are 19 generally commercially available but not in segment form. Such synthetic diamond is formed in the shape of a full circular 21 cylinder having one planar end perpendicular to the longitudinal 22 axis of the cylindrical shape and an opposing domed end, 23 generally formed in the shape of a circular cone. Such elements 24 are typically available in a variety of sizes with the above described shape.
227 According to the present invention, the full cylindrical page 12 3~5 1 ¦ diamond element is segmented to form a cylindrical segment 2 ¦ wherein the segment is then axially disposed within a bit tooth.
3 ¦ Such segmented or split cylindrical elements thus provide a 4 ¦ cutting element with improved cutting efficiency with less use of diamond material and less tendency to dull or polishG The 6 present invention and its various embodiments may be better 7 understood by now turning to Figure 1.
9 ~igure 1 is a cross-sectional view of a first embodiment of the present invention showing a tooth, generally denoted by 11 reference numeral 10, incorporating a diamond cutting element, 12 gener~lly denoted by reference numeral 12. Element 12 is axially 13 disposed within the tungsten-carbide matrix material 14 of the 14 rotating bit. ln other words, longitudinal axis 16 of element 12 is oriented to be approximately perpendicular to bit surface 18 16 at the location of tooth 10. Bit surface 18 may be bit face of a 17 crown of a rotating bit or may be the superior sur face of a 18 raised land or pad disposed upon a bit crown. In either case, 19 bit surface 18 is taken in the present description as the basal 2 surface upon which tooth 10 is disposed.
2 As better seen in Figure 2, element 12 is approximately 2 a quarter section or 90 degrees of the full cylindrical shape of 2 the PCD element normally available. Element 12 is cut using a 2 conven~ional laser cutter. For example, deep cuts are made every 26 ¦ 90 degrees parallel to the longitudinal axis 16 of a full 27 ¦ cylindrical diamond element. Although the laser could be used to 28 l page 13 Il ~L218355 1 completely cut through the diamond element, it has been found 2 ¦ possible that with deep ~coring, the diamond can then be 3 ¦ fractured with propagation of the fracture lying approximately 4 ¦ along the continuation of the plane of the laser cut. For S ¦ example, the laser may cut a millimeter or less into and along 6 ¦ the length of the full cylindrical diamond element.
7 ¦ diametrically opposed cut of equal depth is also provided on the 8 ¦ cylinder. Thereafter, the cylinder may be split in half and then 9 ¦ later quartered on another laser cut by fracturing the diamond 10 ¦ element using an impulsive force and chisel.
12 ¦ Diamond element 12 is disposed within tooth 10 as 13 ¦ isshown in Figure 2 so that the apical edge 20 of diamond 12 14 ¦ formed by the cleavage planes or laser cuts which have formed 15 ¦ radial surfaces 22, is oriented in the leading or forward 16 ¦ direction of tooth 10 as defined by the rotation of the bit upon 17 ¦ which tooth 10 is disposed.
18 l 19 ¦ Turning again ~o Figure 1, it can be seen ~hat a portion 20 ¦ of element 12 is fully exposed above bit surface 18 and in 21 ¦ particular, that apical edge 20 forms the foremost portion of 22 ¦ diamond element 12 as the tooth moves forwardly in the plane of 23 ¦ the figure. Surfaces 22 define a dihedral angle and the 24 ¦ tangential direction of movement of tooth 10 during normal
25 ¦ cutting operation is generally along the direction of the
26 ¦ bisector of the dihedral angle. In the illustrated embodiment a
27 ¦ channel 24 is defined immediately in front of apical edge 20 to
28 l ¦ page 14 1 serve as a waterway or collector as appropriate. Thus, leading 2 ¦ 6urfaces 22 and edge 20 can be placed virtually in channel 24 or 3 ¦ immediately next thereto, forming as shown in Figure 1, one wall 4 ¦ of channel 24 or a portion thereof, whereby hydraulic fluid 5 ¦ supplied to and f lowing through channel 24 dur ing normal drilling 6 ¦ operations will serve to cool and clean the cutting face of tooth 7 ¦ 10 and in particular the leading edge and surfaces of diamond 8 ¦ element 12s 9 l 10 ¦ Further, in the illustrated embodiment, tooth 10 is 11 ¦ shown as having a trailing support 26 of matrix material 12 ¦ integrally formed with matrix material 14 of the bit and 13 I extending above bit surface 18 to the trailing surface of diamond 14 ¦ element 12. The slope of trailing support 26 is chosen so as to substantially match the slope of the top conical surface 28 of 16 element 12 with the opposing end of element 12, which i5 a right 17 circular plane, being embedded within matrix material 14.
18 However, it must be understood that the exact shape and placement 19 of trailing support ~6 can be varied without departing from the spirit and scope of the present invention. For example, with 21 larger dia~eter elements 12, cut from large diameter synthetic 22 cylinders, no trailing support 26 may be provi~ed at all and 23 element 12 may be totally free standing above bit surface 18 like 24 an embedded st~d. In the cases of thinner cylindrical elements 12~ trailing support 26 may be even more subs~antial than that 26 shown in Figure 1 and may assume a slope different from surface 27 28 of element 12 to thereby provide additional matrix reinforcing page lS
~21~35~
1 material behind and on top of conical surface 28 and leading 2 surfaces 22.
4 Figure 2 illustrates in plan view the tooth of Figure 1 in a double row or triad configuration. In other words, a first 6 row of teeth including teeth lOa and lOb is succeeded by a 7 trailing tooth or second row of teeth including tooth lOc, 8 wherein tooth lOc is placed halfway between the spacing of teeth : lOa and lOb. Therefore, it can be appreciated that as the teeth lOa-c move forward during cùtting of a rock formation, the 11 diamond cutting elements incorporated within each of the teeth 12 effectively overlap and provide a uniform annular swath cut into 1 the rock formation as the bit rotates. Figure 4, which shows in F plan view a coring bit incorporating the teeth of Figures 1 and 2 1 illustrates ~he disposition of such a double row of configured 1 teeth, collectively denoted by reference numeral 32, on pad 30.
1 Bit 34 also includes an inner gage 44 wherein the inner and outer gage are connected by waterways 31. Each pad 30 begins 2 at or near inner gage 44 and is disposed across the bit face in a 21 generally radial direction as seen in Figure 4 and splits into 2 two pads which then extend to outer gage 36. The bifurcated pads 2 are separated by a collector 33 which communicates with a gage 24 collector 35 or junk slot 37 as may be appropriate. Clearly, 2 other types of coring bits and petroleum bits could have been 2 illustrated to show the use of the teeth of Figures 1-3 other 2 than the particular bit illustrated in Figure 4. Therefore, the page 16 33~iS
1 inventisn is not to be limited ~o any particular bit style or in 2 fact, even to rotating bits.
4 Turning now to Figure 3, a cross-sectional view of the shoulder-to-gage transition utilizing the teeth of Figures l and 6 2 is illustrated. The bit, generally denoted by reference 7 numeral 341 is characterized by having a vertical cylindrical 8 section or gage 36 which serves to define and maintain the 9 diameter of the bore drilled by bit 34. Below gage 36, bit 34 will slope inwardly along a designed curve toward the center of 11 the bit. In the example of coring bit of Figure 4, a half 12 profile is shown in Figure 5 and is a simple elliptical cross 13 section characterized by an outer shoulder 38, nose 40 and inner 14 shoulder 42. Inner diameter of the core is then defined by inner gage 44. Iurning again to Figure 3, outer gage 36 is shown as 16 incorporating a half cylindrical segment 46, which is surface set 17 and embedded into gage 36 so that the rounded cylindrical surface 18 48 is exposed above bit surface 50 of gage 36 with the flat l9 longitudinal face 52 of the half cylindrical segment embedded 2 within matrix material 54 of bit 34. Half cylindrical diamond 21 crystalline element 46 is more clearly depicted in 22 cross-sectional view in Figure 4 on gage 36.
24 Moving from gage 36 to outer shoulder 38, teeth 32 as shown in Figure 4 include quarter cylindrical segments, shown in 26 rear view in Figure 3 as exemplified by diamond elements 56 and 2 58. Each element 56 is disposed within bit 34 so as to extend page 17 ~2~835~;
1 therefrom in a perpendicular direction as defined by the normal 2 to bit surface at each point where such element is located.
4 ¦In the preferred embodiment each element 56 and 58 is 5 ¦exposed by a uniform amount, n~mely, 2.7 mm (0.105n) above the 6 1 bit face. Element 56 which is the diamond element closest to 7 ¦ gage 36 is placed upon shoulder 38 at such a position nex~ to the 8 ¦ beginning of gage 36 so that its outermost radially extending 9 ¦ point, namely, apex 60, extends radially from the longitudinal 10 1 axis of rotation of bit 34 by an amount equal to the radial 11 ¦ distance from the longitudinal axis of bit 34 by the gage 12 ¦ diamonds, in particular diamond 46. ~or example, in the 13 ¦ preferred embodiment, gage diamond 46 e~tends above bit surface 14 1 50 by 0.64 mm (0.025"). While element 56 extends above bit face 15 ¦ 50 by 2.7 mm (0.105") it is placed as th~ first tooth on the bit 16 ¦ face at ~uch a distance from the gage 36 that the radially 17 I outermost exposed portion of diamond element 56 will equal the 18 ¦ radial distance of the gage diamonds 46 from the axis of rotation 21 ~ of bit 34.
I Thus, as illustrated in Figure 6, which shows a plan 22 ¦ view of the gage of the bit of Figure 4, a double row of gage 23 ¦ diamonds 46a is disposed at and slightly below gage level 62 on a I type I gage column corresponding to a type I pad 30 shown in plan 25 ¦ view in ~igure 4. Gage diamonds 46b are thus placed adjacent to 26 ¦ a pad of type II and gage diamonds 46c placed on a gage section 27 ¦ correspondingg to a type III pad. Gage diamonds 46a-c thus form ~8 1 page 18 !1 12~L8;35S
1 a staggered pattern as best illustrated in Figure 6 which 2 effectively presents a high cutting element density as the bit 3 rotates. Above gage diamonds 46a-46b are conventional natural 4 diamonds surface set in broaches, namely~ kickers which are typical of the order of 6 per carat in size. Whereas the double 6 row of diamonds within one gage section are offset from each 7 other by approximately half a unit spacing, a unit spacing being 8 defined as the length of a gage diamond 46, the adjacent row of 9 teeth on the next adjacent gage section begins at a quarter spacing displaced from the corresponding row of gage diamonds on 11 the adjacent pad. In other words, while type I pad corresponds 12 to gage diamonds 46a having two rows with each row offset by half 13 a space between each other, pad II corresponds to gage diamonds 14 46b which are similarly offset with respect to each other and are spaced down the gage one quarter of a spacing as compared to 16 gage diamonds 46a on pad type I.
Turning now to Figure 7, a second embodiment of the 1 present invention is illustrated wherein a tooth, generally 2 denoted by reference numeral 66, incorporates a half cylindrical 21 segment diamond element 68 extending from and embedded in matrix 22 material 14 in much the same manner as illustrated in connection 23 with the iirst embodiment of Figures l and 2. As better seen in 24 plan view of Figure 8, PCD element 68 is characterized by a half 2 cylindrical surface 70 and a planar leading surface 7~, which is 2 formed as described above by cleaving a full cylinder along the 2 diameter.
page 19 Il lZ1835~; ~
1 Turning 2gain to ~igure 7, diamond element 68 also 2 includes a conical or domed upper surface 74 forming the apical 3 point 76 of element 68. A trailing support 78 of integrally 4 formed matrix material is smoothly fared from surface 74 to bit face 18 to provide tangential reinforcement and support for 6 diamond element 68 against the cutting forces to which element 68 7 is subjected. As better seen in plan view in Figure 8, trailing 8 supports 78 are tapered to a point 80 on bit face 18 thereby 9 forming a teardrop shaped plan outline for tooth 66.
11 As shown in Figure 7, diamond element 68 is placed 12 immediately adjacent to and forms one side of a channel 80 formed 13 into matrix material 14 which channel ao serve~ as a conventional 14 waterway or collector as may be appropriate with the same advantages as described in connection with the first embodiment 16 of Figure 1.
18 As described in connection with ~igure 2, the second 19 embodiment of Figure 8 similarly consists of two rows of teeth 2 66a and 66b followed by a second row represented by tooth 66c.
21 Tooth 66c is located halfway between the spacing between tooth 22 66a and 66b ac defined with respect to the direction of 23 tangential movement durlng normal drilling operations. Ihe 24 double row of teeth are disposed on a petroleum or coring bit in the same manner as illustrated in connection with the first 26 embodiment of the invention in Figure 4. Teeth 66 are thus 27 disposed within matrix material 14 and used on a bit in the s~me page 20 ~Z3L835~
1 manner as are teeth 10 of Figures 1 and 2. ~owever, teeth 66 as 2 shown in Figure 8, clearly provide a broader cutting surface and 3 a diamond element 68 containing twice the diamond material and 4 structural bulk as compared to diamond elements 12 of the first embodiment. Therefore, in those applications where a larger 6 cutting bite is required or where greater structural strength is 7 needed in ~he diamond element, the half cylindrical split 8 elements 68 of the second embodiment may be more advantageously 9 used than the quarter split diamond elements of the first embodiment.
12 Many alterations and modifications may be made ~o the 13 present invention without departing from its spirit and scope.
14 For example, although the split cylindrical segment has been shown as perpendicularly embedded into the matrix material, it is 16 clearly contemplated that it may be either forwardly or 17 rearwardly raked if required by design objectives. Therefore, 18 the illustrated embodiment must be understood as presented only 19 as an example of the invention and should not be taken as limiting the invention as set forth in the following claim.
page 21
18 However, it must be understood that the exact shape and placement 19 of trailing support ~6 can be varied without departing from the spirit and scope of the present invention. For example, with 21 larger dia~eter elements 12, cut from large diameter synthetic 22 cylinders, no trailing support 26 may be provi~ed at all and 23 element 12 may be totally free standing above bit surface 18 like 24 an embedded st~d. In the cases of thinner cylindrical elements 12~ trailing support 26 may be even more subs~antial than that 26 shown in Figure 1 and may assume a slope different from surface 27 28 of element 12 to thereby provide additional matrix reinforcing page lS
~21~35~
1 material behind and on top of conical surface 28 and leading 2 surfaces 22.
4 Figure 2 illustrates in plan view the tooth of Figure 1 in a double row or triad configuration. In other words, a first 6 row of teeth including teeth lOa and lOb is succeeded by a 7 trailing tooth or second row of teeth including tooth lOc, 8 wherein tooth lOc is placed halfway between the spacing of teeth : lOa and lOb. Therefore, it can be appreciated that as the teeth lOa-c move forward during cùtting of a rock formation, the 11 diamond cutting elements incorporated within each of the teeth 12 effectively overlap and provide a uniform annular swath cut into 1 the rock formation as the bit rotates. Figure 4, which shows in F plan view a coring bit incorporating the teeth of Figures 1 and 2 1 illustrates ~he disposition of such a double row of configured 1 teeth, collectively denoted by reference numeral 32, on pad 30.
1 Bit 34 also includes an inner gage 44 wherein the inner and outer gage are connected by waterways 31. Each pad 30 begins 2 at or near inner gage 44 and is disposed across the bit face in a 21 generally radial direction as seen in Figure 4 and splits into 2 two pads which then extend to outer gage 36. The bifurcated pads 2 are separated by a collector 33 which communicates with a gage 24 collector 35 or junk slot 37 as may be appropriate. Clearly, 2 other types of coring bits and petroleum bits could have been 2 illustrated to show the use of the teeth of Figures 1-3 other 2 than the particular bit illustrated in Figure 4. Therefore, the page 16 33~iS
1 inventisn is not to be limited ~o any particular bit style or in 2 fact, even to rotating bits.
4 Turning now to Figure 3, a cross-sectional view of the shoulder-to-gage transition utilizing the teeth of Figures l and 6 2 is illustrated. The bit, generally denoted by reference 7 numeral 341 is characterized by having a vertical cylindrical 8 section or gage 36 which serves to define and maintain the 9 diameter of the bore drilled by bit 34. Below gage 36, bit 34 will slope inwardly along a designed curve toward the center of 11 the bit. In the example of coring bit of Figure 4, a half 12 profile is shown in Figure 5 and is a simple elliptical cross 13 section characterized by an outer shoulder 38, nose 40 and inner 14 shoulder 42. Inner diameter of the core is then defined by inner gage 44. Iurning again to Figure 3, outer gage 36 is shown as 16 incorporating a half cylindrical segment 46, which is surface set 17 and embedded into gage 36 so that the rounded cylindrical surface 18 48 is exposed above bit surface 50 of gage 36 with the flat l9 longitudinal face 52 of the half cylindrical segment embedded 2 within matrix material 54 of bit 34. Half cylindrical diamond 21 crystalline element 46 is more clearly depicted in 22 cross-sectional view in Figure 4 on gage 36.
24 Moving from gage 36 to outer shoulder 38, teeth 32 as shown in Figure 4 include quarter cylindrical segments, shown in 26 rear view in Figure 3 as exemplified by diamond elements 56 and 2 58. Each element 56 is disposed within bit 34 so as to extend page 17 ~2~835~;
1 therefrom in a perpendicular direction as defined by the normal 2 to bit surface at each point where such element is located.
4 ¦In the preferred embodiment each element 56 and 58 is 5 ¦exposed by a uniform amount, n~mely, 2.7 mm (0.105n) above the 6 1 bit face. Element 56 which is the diamond element closest to 7 ¦ gage 36 is placed upon shoulder 38 at such a position nex~ to the 8 ¦ beginning of gage 36 so that its outermost radially extending 9 ¦ point, namely, apex 60, extends radially from the longitudinal 10 1 axis of rotation of bit 34 by an amount equal to the radial 11 ¦ distance from the longitudinal axis of bit 34 by the gage 12 ¦ diamonds, in particular diamond 46. ~or example, in the 13 ¦ preferred embodiment, gage diamond 46 e~tends above bit surface 14 1 50 by 0.64 mm (0.025"). While element 56 extends above bit face 15 ¦ 50 by 2.7 mm (0.105") it is placed as th~ first tooth on the bit 16 ¦ face at ~uch a distance from the gage 36 that the radially 17 I outermost exposed portion of diamond element 56 will equal the 18 ¦ radial distance of the gage diamonds 46 from the axis of rotation 21 ~ of bit 34.
I Thus, as illustrated in Figure 6, which shows a plan 22 ¦ view of the gage of the bit of Figure 4, a double row of gage 23 ¦ diamonds 46a is disposed at and slightly below gage level 62 on a I type I gage column corresponding to a type I pad 30 shown in plan 25 ¦ view in ~igure 4. Gage diamonds 46b are thus placed adjacent to 26 ¦ a pad of type II and gage diamonds 46c placed on a gage section 27 ¦ correspondingg to a type III pad. Gage diamonds 46a-c thus form ~8 1 page 18 !1 12~L8;35S
1 a staggered pattern as best illustrated in Figure 6 which 2 effectively presents a high cutting element density as the bit 3 rotates. Above gage diamonds 46a-46b are conventional natural 4 diamonds surface set in broaches, namely~ kickers which are typical of the order of 6 per carat in size. Whereas the double 6 row of diamonds within one gage section are offset from each 7 other by approximately half a unit spacing, a unit spacing being 8 defined as the length of a gage diamond 46, the adjacent row of 9 teeth on the next adjacent gage section begins at a quarter spacing displaced from the corresponding row of gage diamonds on 11 the adjacent pad. In other words, while type I pad corresponds 12 to gage diamonds 46a having two rows with each row offset by half 13 a space between each other, pad II corresponds to gage diamonds 14 46b which are similarly offset with respect to each other and are spaced down the gage one quarter of a spacing as compared to 16 gage diamonds 46a on pad type I.
Turning now to Figure 7, a second embodiment of the 1 present invention is illustrated wherein a tooth, generally 2 denoted by reference numeral 66, incorporates a half cylindrical 21 segment diamond element 68 extending from and embedded in matrix 22 material 14 in much the same manner as illustrated in connection 23 with the iirst embodiment of Figures l and 2. As better seen in 24 plan view of Figure 8, PCD element 68 is characterized by a half 2 cylindrical surface 70 and a planar leading surface 7~, which is 2 formed as described above by cleaving a full cylinder along the 2 diameter.
page 19 Il lZ1835~; ~
1 Turning 2gain to ~igure 7, diamond element 68 also 2 includes a conical or domed upper surface 74 forming the apical 3 point 76 of element 68. A trailing support 78 of integrally 4 formed matrix material is smoothly fared from surface 74 to bit face 18 to provide tangential reinforcement and support for 6 diamond element 68 against the cutting forces to which element 68 7 is subjected. As better seen in plan view in Figure 8, trailing 8 supports 78 are tapered to a point 80 on bit face 18 thereby 9 forming a teardrop shaped plan outline for tooth 66.
11 As shown in Figure 7, diamond element 68 is placed 12 immediately adjacent to and forms one side of a channel 80 formed 13 into matrix material 14 which channel ao serve~ as a conventional 14 waterway or collector as may be appropriate with the same advantages as described in connection with the first embodiment 16 of Figure 1.
18 As described in connection with ~igure 2, the second 19 embodiment of Figure 8 similarly consists of two rows of teeth 2 66a and 66b followed by a second row represented by tooth 66c.
21 Tooth 66c is located halfway between the spacing between tooth 22 66a and 66b ac defined with respect to the direction of 23 tangential movement durlng normal drilling operations. Ihe 24 double row of teeth are disposed on a petroleum or coring bit in the same manner as illustrated in connection with the first 26 embodiment of the invention in Figure 4. Teeth 66 are thus 27 disposed within matrix material 14 and used on a bit in the s~me page 20 ~Z3L835~
1 manner as are teeth 10 of Figures 1 and 2. ~owever, teeth 66 as 2 shown in Figure 8, clearly provide a broader cutting surface and 3 a diamond element 68 containing twice the diamond material and 4 structural bulk as compared to diamond elements 12 of the first embodiment. Therefore, in those applications where a larger 6 cutting bite is required or where greater structural strength is 7 needed in ~he diamond element, the half cylindrical split 8 elements 68 of the second embodiment may be more advantageously 9 used than the quarter split diamond elements of the first embodiment.
12 Many alterations and modifications may be made ~o the 13 present invention without departing from its spirit and scope.
14 For example, although the split cylindrical segment has been shown as perpendicularly embedded into the matrix material, it is 16 clearly contemplated that it may be either forwardly or 17 rearwardly raked if required by design objectives. Therefore, 18 the illustrated embodiment must be understood as presented only 19 as an example of the invention and should not be taken as limiting the invention as set forth in the following claim.
page 21
Claims (14)
1. A rotating bit characterized by a longitudinal axis of rotation for use in earth boring comprising:
a matrix body member having portions forming a gage and a face, said face including a plurality of channels forming pad means between at least some of the adjacent channels, each said pad means including a plurality of spaced synthetic polycrystalline diamond cutting elements mounted directly in the matrix during matrix formation, each of said cutting elements being of a predetermined geometric shape and being temperature stable to at least about 1200 degrees C., the said cutting elements including a portion received within the matrix member of said pad means and a portion which extends above the surface of said pad means and which is adapted to form the cutting face of said cutting element, each cutting element including a generally curved rear face and a cutting face, at least some of said cutting elements having a longitudinal axis and being characterized in shape as a segment of a cylinder including at least one planar surface, said planar surface forming at least in part a leading surface of said cutting face, said longitudinal axis of said cutting element lying in a plane parallel to said longitudinal axis of rotation of said bit, and the portion of said cutting elements which forms the cutting face of said cutting elements extending more than 0.5 mm above the surface of the corresponding pad.
a matrix body member having portions forming a gage and a face, said face including a plurality of channels forming pad means between at least some of the adjacent channels, each said pad means including a plurality of spaced synthetic polycrystalline diamond cutting elements mounted directly in the matrix during matrix formation, each of said cutting elements being of a predetermined geometric shape and being temperature stable to at least about 1200 degrees C., the said cutting elements including a portion received within the matrix member of said pad means and a portion which extends above the surface of said pad means and which is adapted to form the cutting face of said cutting element, each cutting element including a generally curved rear face and a cutting face, at least some of said cutting elements having a longitudinal axis and being characterized in shape as a segment of a cylinder including at least one planar surface, said planar surface forming at least in part a leading surface of said cutting face, said longitudinal axis of said cutting element lying in a plane parallel to said longitudinal axis of rotation of said bit, and the portion of said cutting elements which forms the cutting face of said cutting elements extending more than 0.5 mm above the surface of the corresponding pad.
2. The rotating bit of Claim 1, wherein the cylindrical shape of said cutting element is a circular cylinder.
3. The rotating bit of Claim 1, wherein said bit is a core bit.
4. The rotating bit of Claim 1, wherein at least some of said cutting elements are positioned such that the cutting face is at the junction of at least some of said channels.
5. The rotating bit of Claim 1, wherein said segment of said cylindrical shape is a half cylindrical shape, said planar surface being a planar surface lying along a diameter of said half cylindrical shape.
6. The rotating bit of Claim 1, wherein said segment of said cylindrical shape of said cutting element is characterized by an apical edge defining a dihedral angel of less than 180 degrees.
7. The rotating bit of Claim 1, wherein a trailing support of matrix is disposed behind said cutting element and is contiguous thereto and is tapered from the trailing surface of said cutting element.
8. A rotating bit characterized by a longitudinal axis of rotation for use in earth boring comprising:
a matrix body member having portions forming a gage and a face, a plurality of spaced synthetic polycrystalline diamond cutting elements mounted directly in the matrix of said face of said body matrix during matrix formation, said bit including a plurality of waterways, each of said cutting elements being of a predetermined geometric shape and being temperature stable to at least about 1200 degrees C., each of said cutting elements having a front cutting face and a rear portion which extends above said body matrix, and each of said cutting elements including a portion received within said body matrix, at least some of said cutting elements having a longitudinal axis and being characterized in shape as a segment of a cylinder including at least one planar surface, said planar surface forming at least in part a leading surface of said cutting face, said longitudinal axis of said cutting element lying in a plane parallel to said longitudinal axis of rotation of said bit, and said at least some of said cutting elements extending more than 0.5 mm above the face of said matrix in which they are mounted.
a matrix body member having portions forming a gage and a face, a plurality of spaced synthetic polycrystalline diamond cutting elements mounted directly in the matrix of said face of said body matrix during matrix formation, said bit including a plurality of waterways, each of said cutting elements being of a predetermined geometric shape and being temperature stable to at least about 1200 degrees C., each of said cutting elements having a front cutting face and a rear portion which extends above said body matrix, and each of said cutting elements including a portion received within said body matrix, at least some of said cutting elements having a longitudinal axis and being characterized in shape as a segment of a cylinder including at least one planar surface, said planar surface forming at least in part a leading surface of said cutting face, said longitudinal axis of said cutting element lying in a plane parallel to said longitudinal axis of rotation of said bit, and said at least some of said cutting elements extending more than 0.5 mm above the face of said matrix in which they are mounted.
9. The rotating bit of Claim 8, wherein said bit is a core bit.
10. The rotating bit of Claim 9, wherein a trailing matrix support formed during matrix formation is disposed behind the rear portion of said cutting elements to provide support for the portion of said cutting elements which extend above said body matrix.
11. The rotating bit of Claim 8, wherein said cylindrical shape of said cutting element is a circular cylinder.
12. The rotating bit of Claim 8, wherein said cylindrical shape is a half cylindrical shape, said planar surface being a planar surface lying along a diameter of said half cylindrical shape.
13. The rotating bit of Claim 8, wherein said bit includes a sloping shoulder, at least some of said cutting elements being exposed on said shoulder near said gage and extending above said bit face by a first predetermined distance, said gage including cutting elements disposed above said bit face of said gage by a second predetermined distance, the radial distance of said cutting elements disposed and extending above said gage from said longitudinal axis of rotation of said bit being approximately equal to the radial distance from said longitudinal axis of rotation of said bit of an uppermost one of said cutting elements disposed on said shoulder, said uppermost cutting element on said shoulder being positioned on said shoulder next to said gage at a location such that said radial distances of said cutting elements on said gage and of said uppermost cutting element from said longitudinal axis of rotation of said bit being set approximately equal.
14. The rotating bit of Claim 8, wherein a plurality of rows of said cutting elements are disposed on said bit and wherein said rows are paired to form a first and second related row, the distance of spacing between said cutting elements within said first and second row being substantially constant, said cutting elements of said second row being disposed behind the cutting elements of said first row as defined by tangential motion of said cutting elements during rotation of said bit during normal cutting operations, said cutting elements of said second row being readily disposed between said cutting elements of said first row, whereby said cutting elements of said first and second rows cut a uniform annular swath as said bit rotates of a higher effective cutting element density than achievable by the cutting element density within said first or second row alone, said cutting elements of said second row following behind said cutting elements of said first row in the gaps between and behind said cutting elements of said first row.
..
..
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US47706883A | 1983-03-21 | 1983-03-21 | |
| US477,068 | 1983-03-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1218355A true CA1218355A (en) | 1987-02-24 |
Family
ID=23894393
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000450039A Expired CA1218355A (en) | 1983-03-21 | 1984-03-20 | Tooth design using cylindrical diamond cutting elements |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0119620B1 (en) |
| JP (1) | JPS6016692A (en) |
| AU (1) | AU2568884A (en) |
| BR (1) | BR8401280A (en) |
| CA (1) | CA1218355A (en) |
| DE (1) | DE3481435D1 (en) |
| ZA (1) | ZA842109B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN86100885A (en) * | 1985-01-25 | 1986-08-20 | 诺顿-克里斯坦森公司 | A kind of improved groove chipping type bit |
| US4673044A (en) * | 1985-08-02 | 1987-06-16 | Eastman Christensen Co. | Earth boring bit for soft to hard formations |
| GB2188354B (en) * | 1986-03-27 | 1989-11-22 | Shell Int Research | Rotary drill bit |
| CL2008002641A1 (en) | 2007-09-05 | 2009-11-20 | Groupe Fordia Inc | Drilling bit that is used with a fluid, comprises a section of the body that has a conduit to receive the fluid, a section of an annular crown that is in fluid communication with the conduit of the body, a flow direction component that cooperates with the section of the crown, where the latter reaches a predetermined wear threshold. |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5382601A (en) * | 1976-12-28 | 1978-07-21 | Tokiwa Kogyo Kk | Rotary grinding type excavation drill head |
| US4351401A (en) * | 1978-06-08 | 1982-09-28 | Christensen, Inc. | Earth-boring drill bits |
| US4373593A (en) * | 1979-03-16 | 1983-02-15 | Christensen, Inc. | Drill bit |
| DE3114749C2 (en) * | 1981-04-11 | 1983-10-27 | Christensen, Inc., 84115 Salt Lake City, Utah | Wedge-shaped cutting link for rotary drill bits for deep drilling |
| US4529047A (en) * | 1983-02-24 | 1985-07-16 | Norton Christensen, Inc. | Cutting tooth and a rotating bit having a fully exposed polycrystalline diamond element |
-
1984
- 1984-03-16 AU AU25688/84A patent/AU2568884A/en not_active Abandoned
- 1984-03-19 EP EP84102985A patent/EP0119620B1/en not_active Expired - Lifetime
- 1984-03-19 JP JP59051265A patent/JPS6016692A/en active Pending
- 1984-03-19 DE DE8484102985T patent/DE3481435D1/en not_active Expired - Lifetime
- 1984-03-20 CA CA000450039A patent/CA1218355A/en not_active Expired
- 1984-03-20 BR BR8401280A patent/BR8401280A/en unknown
- 1984-03-21 ZA ZA842109A patent/ZA842109B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| BR8401280A (en) | 1984-10-30 |
| ZA842109B (en) | 1984-11-28 |
| AU2568884A (en) | 1984-09-27 |
| DE3481435D1 (en) | 1990-04-05 |
| EP0119620B1 (en) | 1990-02-28 |
| JPS6016692A (en) | 1985-01-28 |
| EP0119620A3 (en) | 1986-02-12 |
| EP0119620A2 (en) | 1984-09-26 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |