GB2032979A - Improved Cutter Shapes for Rock Drilling With Drag Bits - Google Patents
Improved Cutter Shapes for Rock Drilling With Drag Bits Download PDFInfo
- Publication number
- GB2032979A GB2032979A GB7929100A GB7929100A GB2032979A GB 2032979 A GB2032979 A GB 2032979A GB 7929100 A GB7929100 A GB 7929100A GB 7929100 A GB7929100 A GB 7929100A GB 2032979 A GB2032979 A GB 2032979A
- Authority
- GB
- United Kingdom
- Prior art keywords
- cutter
- rock
- cutter element
- configuration
- boron nitride
- 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.)
- Granted
Links
- 239000010432 diamond Substances 0.000 claims abstract description 23
- 239000011435 rock Substances 0.000 claims abstract description 23
- 229910003460 diamond Inorganic materials 0.000 claims abstract description 22
- 229910052582 BN Inorganic materials 0.000 claims abstract description 14
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000002131 composite material Substances 0.000 claims abstract description 13
- 238000005553 drilling Methods 0.000 claims abstract description 13
- 229910052984 zinc sulfide Inorganic materials 0.000 claims abstract description 7
- 230000000694 effects Effects 0.000 claims abstract description 5
- 238000005520 cutting process Methods 0.000 claims description 18
- 239000000758 substrate Substances 0.000 claims description 9
- 239000010941 cobalt Substances 0.000 claims description 5
- 229910017052 cobalt Inorganic materials 0.000 claims description 5
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical group [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- 230000035515 penetration Effects 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 238000005755 formation reaction Methods 0.000 description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 239000011159 matrix material Substances 0.000 description 3
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 235000015076 Shorea robusta Nutrition 0.000 description 2
- 244000166071 Shorea robusta Species 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 238000010408 sweeping Methods 0.000 description 1
- 230000008542 thermal sensitivity Effects 0.000 description 1
- 230000007704 transition Effects 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
- E21B10/5673—Button-type inserts with preformed cutting elements mounted on a distinct support, e.g. polycrystalline inserts having a non planar or non circular cutting face
-
- 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
- E21B10/58—Chisel-type inserts
Abstract
A rock cutter (10) for improving the drilling performance of drag-type bits includes a body portion (12) and a cutter element (14) having an outer surface shaped to create a plowing effect so as to direct rock chips away from the surface. The cutter element is preferably V-shaped and formed of a composite compact of diamond cubic boron nitride or wurtzite boron nitride. <IMAGE>
Description
SPECIFICATION
Improved Cutter Shapes for Rock Drilling with
Drag Bits
This invention relates to oil and rock drilling bits and, more particularly, to the use of cutting elements in shaped configurations, preferably formed of composite compacts of diamond, cubic boron nitride (CBN), or wurtzite boron nitride (WBN), for rock drilling.
Drag type rotary bits are commonly fabricated using natural diamond crystals. These bits are used for hard abrasive drilling in deep formations.
Such drilling is typically characterized by slow penetration rates (2 to 4 ft/hr) and long bit life (up to 300 hrs). Because of thermal sensitivity of diamonds and the necessity for cooling and cleaning of the individual cutters, good fluid hydraulics are essential to economic bit performance. To obtain acceptable levels of bit hydraulics, diamond bit fabricators have historically used low cutter exposure levels of the individual diamond stones. Conventional diamond drag bits contain individual surface set stones which have exposures or engagements into the rock of the order of 1/1 6 inch maximum.
It has been recently proposed to use synthetic diamond compacts both cluster and composite as the cutting elements in rotary bits. Such compacts are preferably made in accordance with
U.S. Patent No. 3,745,623.
The advent of such drill blanks, e.g., a sintered diamond layer intimately bonded to a cobalt cemented tungsten carbide layer, has provided a rock cutting tool which permits much more aggressive cutting of hard sandy shales and other abrasive formations. Although drag bits fabricated from these diamond compact blanks are capable of faster penetration rates and equivalent or longer life than diamond drag bits, achievement of optimum performance is often limited by the adherence of the shale, which is under confining pressure, to the sintered diamond cutting surface.
Such sticking or loading up of the individual cutters leads to reduced penetration rates and overheating of the cutters, thereby creating reduced abrasion resistance and shortened bit life.
Drag bits fabricated using diamond compacts have historically exhibited much higher exposure levels and thus greater potential engagement of the rock workpiece. These cutters are known to machine the rock which exhibits plastic deformation under the confining pressures which exist at typical well depths of 5,000 to 15,000 or more feet. These cutters are placed on the bit usually at negative 5 to negative 250 angle of rake of the cutting edge. The cutting edges are usually round or straight and the chips of plastic
rock are forced up the flat surface of the sintered diamond layer. In order to provide cleaning and
cooling of this sintered diamond surface, necessary to maintain a sharp cutting edge, the bit is designed to channel the drilling mud in a sweeping mode across the cutter surface.In practice it is usually difficult to provide this type of hydraulic action when the desired cutter exposure of 1/4 inch or more is present.
A cutter of the present invention overcomes the drawbacks of the prior art with the use of a pre-selected cutter shape geometry which creates a plowing action against the plastic rock chips.
The cutter includes a plow shaped cutting element, preferably a cutting element of composite compact having a generally V-shaped plow geometry. The included angle of the Vshaped element is advantageously in the range of 600 to 900, most advantageously about 750. The cutter element may be fabricated from diamond compacts and subsequently bonded to the bit or to a cutter body for later attachment to the bit by any of the conventional attachment techniques.
The cutter element geometry of this invention permits maintaining aggressive cutting action and longer cutting life by eliminating the tendency for cutters to load up or become occluded by the sticky plastic shales. By generating a rock chip flow which inherently moves away from the cutter surface rather than building up on the cutter surface, the critical requirements for bit hydraulics are reduced. This permits maintenance of maximum cutter exposure and associated high penetration rates for the rock drilling operation.
In order that the invention may be clearly understood, a preferred embodiment thereof will now be described by way of example only with reference to the accompanying drawings, in which:
Figure 1 is a schematic front elevation view of an exemplary cutter and cutter element for dragtype bits in accordance with the present invention;
Figure 2 is a schematic side elevation view of the cutter; and
Figure 3 is a schematic top plan view of the cutter.
Figure 1 shows a cutter 10 of the present invention. Cutter 10 includes a body portion 12 and a cutting element 14. Body portion 12, while illustrated as being generally rectangular in crosssection, may be of any convenient shape for
mounting on a drag-type bit for oil and gas drilling in various strata formations. In use, a plurality of cutters 10 or individual cutter elements 14 or both would be attached to the drill crown of a rotary bit at suitable rake angles for the intended drilling.
It has been discovered that by providing cutter
10 with a shaped cutting surface, the cutting surface tends to plow the rock away from the working surface of the cutter. The plowing action reduces substantially or eliminates the loading of the cutter with attendant increase in penetration rates and reduced heating of the cutters.
As shown in the drawings, the shaping of the
cutter surface is achieved by providing a triangular shaped cutter element 14 having a
generally V-shaped cutter surface. The V-shaped surface includes leg portions L which meet at edge E to define an included angle ry, The included angle-surface defined by angle ct should be in the range of from 600 to 900. Most advantageously, the included angle should be about 750. Depending upon the application, it may be advantageous to provide a set back, relief angle of a few degrees, for example p=7 0.
To maintain the sharp cutting edge E under long drilling times, it is preferable to construct the cutter element 14 with a superabrasive such as cluster compacts or composite compacts of diamond, cubic boron nitride or wurtzite boron nitride or mixtures thereof. However, the plowing effect may be utilized with other materials as well.
A cluster compact is defined as a cluster of abrasive particles bonded together either (1) in a self-bonded relationship, (2) by means of bonding medium disposed between the crystals, (3) by means of some combination of (1) and (2).
Reference can be made of U.S. 3,136,615; U.S.
3,141,746 and U.S. 3,233,988 for a detailed disclosure of certain types of compacts and methods for making same. (The disclosures of these patents are hereby incorporated by reference herein).
A composite compact is defined as a cluster compact bonded to a substrate material such as cemented tungsten carbide. A bond to the substrate can be formed either during or subsequent to the formation of the cluster compact. Reference can be made to U.S.
3,745,623; U.S. 3,745,489 and U.S. 3,767,371 for a detailed disclosure of certain types of composite compacts and methods of making same. (The disclosures of these patents are hereby incorporated by reference herein).
The term cemented carbide as used herein means one or more transition carbides of a metal of Groups IVb, Vb, and Vlb of the Periodic Table cemented or bonded by one or more matrix metals selected from the group iron, nickel, and cobalt. A typical cemented carbide contains WC in a cobalt matrix or TiC in a nickel matrix.
Preferably, the V-shaped cutter element 14 is a composite compact which includes a substrate 1 4A of cemented carbide and an abrasive mass or layer 1 4B. The abrasive layer, as previously indicated, may be comprised of an abrasive selected from the group consisting of diamond, cubic boron nitride (CBN), wurtzite boron nitride (WBN), and mixtures of two or more of the foregoing.
As illustrated in the drawing, the cutter element 14 includes a triangular cross-sectioned substrate 1 4A of, for example, cobalt cemented tungsten carbide. Substrate 1 4A may be attached to cutter body 12 by any conventional technique such as brazing by induction heating, or furnacing, or by interference fitting commonly used in full hole oil/gas manufacturing.
Abrasive layer 1 4B is bonded to two legs of substrate 1 4A to provide a generally Vshaped surface, as viewed in Figure 3. This structure provides an elongate working edge E with the angled leg surfaces L providing a plow-like effect on the rock chips. Cutter element 14 may be fabricated in accordance with the above reference
U.S. Patent 3,745,623.
Alternatively, the cutter element 14 may be fabricated by bonding two, flat, diamond composite drill blanks together at a suitable angle to form the plow shape and included angle indicated above. Such flat type composite compacts are commercially available from
General Electric Company under the designation STRATAPAXTM Drill Blanks (polycrystalline diamond on a cemented carbide substrate).
These and other modifications may be made by those skilled in the art without departing from the scope and spirit of the present invention as, defined in the appended claims.
Indeed, those skilled in the art will recognize that the method of drilling comprising contacting a strata formation with a cutting element having a generally Vshaped plow geometry and moving the cutter relative to the strata with the apex as the leading edge causes chip flow to proceed along the plow legs and away from the working edge represents an advance in high penetration drilling.
Claims (10)
1. A rock cutter for use in drag-type oil and gas bits comprising a body portion having a cutter element thereon, said cutter element having a pre-selected outer surface configuration to create a plowing effect and thereby cause rock chip flow away from the cutter element.
2. A rock cutter according to claim 1, wherein said pre-selected configuration is a V-shaped plow configuration.
3. A rock cutter according to claim 1 or claim 2, wherein said cutter element is a composite compact having an abrasive selected from the group consisting of diamond, cubic boron nitride, wurtzite boron nitride and mixtures thereof.
4. A cutter element for use in a rock cutter for drag-type oil and gas bits comprising a composite compact having an abrasive layer selected from the group consisting of diamond, cubic boron nitride, wurtzite boron nitride and mixtures thereof, and a substrate, the abrasive layer of said compact having a generally V-shaped configuration to cause a plowing effect and rock chip flow along the cutter element.
5. A cutter according to claim 2 or cutter element according to claim 4, wherein said Vshaped configuration defines an included angle in the range of from 600 to 900.
6. A cutter or cutter element according to claim 5, wherein said included angle is 750.
7. A cutter element according to claim 4, wherein said composite compact substrate is cobalt cemented carbide.
8. A cutter element for rock drills comprising a polycrystalline layer of diamond, cubic boron nitride, wurtzite boron nitride or mixtures thereof, said layer having a generally V-shaped plow-like configuration defining an included angle in the range of 600 to 900, whereby a plowing action is created to cause chip flow along the element and away from its cutting edge.
9. A method of rock drilling comprising: contacting the strata with a drag-type cutter element having a generally V-shaped outer configuration, said Vshaped configuration defining an included angle in the range of 60 900, and moving said element across the strata with the apex of the V-shape as the leading edge, whereby chip flow proceeds away from the leading edge along the legs of said V-shaped configuration.
10. A rock cutter substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US94786578A | 1978-10-02 | 1978-10-02 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2032979A true GB2032979A (en) | 1980-05-14 |
| GB2032979B GB2032979B (en) | 1982-09-08 |
Family
ID=25486908
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7929100A Expired GB2032979B (en) | 1978-10-02 | 1979-08-21 | Cutter shapes for rock drilling with drag bits |
Country Status (12)
| Country | Link |
|---|---|
| JP (1) | JPS5549490A (en) |
| BE (1) | BE879116A (en) |
| CH (1) | CH646227A5 (en) |
| DE (1) | DE2938524A1 (en) |
| ES (1) | ES257023Y (en) |
| FR (1) | FR2443560A1 (en) |
| GB (1) | GB2032979B (en) |
| IL (1) | IL58031A (en) |
| IT (1) | IT1163718B (en) |
| NL (1) | NL7906559A (en) |
| SE (1) | SE7908122L (en) |
| ZA (1) | ZA794097B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4440246A (en) * | 1981-04-11 | 1984-04-03 | Christensen, Inc. | Cutting member for rotary drill bits |
| EP0149530A2 (en) * | 1984-01-16 | 1985-07-24 | CDP, Ltd. | Self sharpening drag bit assembly |
| EP0151537A2 (en) * | 1984-01-31 | 1985-08-14 | Nl Industries Inc. | Improved drill bit and cutter therefor |
| GB2181472A (en) * | 1985-08-22 | 1987-04-23 | Anderson Strathclyde Plc | Cutter tools and tip inserts therefor |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3039632C2 (en) * | 1980-10-21 | 1982-12-16 | Christensen, Inc., 84115 Salt Lake City, Utah | Rotary bit for deep drilling |
| GB2138864B (en) * | 1983-04-28 | 1986-07-30 | Sumitomo Metal Mining Co | Roller drill bits |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3136615A (en) * | 1960-10-03 | 1964-06-09 | Gen Electric | Compact of abrasive crystalline material with boron carbide bonding medium |
| US3141746A (en) * | 1960-10-03 | 1964-07-21 | Gen Electric | Diamond compact abrasive |
| US3233988A (en) * | 1964-05-19 | 1966-02-08 | Gen Electric | Cubic boron nitride compact and method for its production |
| US3767371A (en) * | 1971-07-01 | 1973-10-23 | Gen Electric | Cubic boron nitride/sintered carbide abrasive bodies |
| US3745623A (en) * | 1971-12-27 | 1973-07-17 | Gen Electric | Diamond tools for machining |
| US3745489A (en) * | 1972-05-01 | 1973-07-10 | Stanford Research Inst | Microwave and uhf filters using discrete hairpin resonators |
| ZA782286B (en) * | 1978-04-21 | 1979-10-31 | Christensen Inc | Abrasive bodies |
-
1979
- 1979-08-07 ZA ZA00794097A patent/ZA794097B/en unknown
- 1979-08-13 IL IL58031A patent/IL58031A/en unknown
- 1979-08-21 GB GB7929100A patent/GB2032979B/en not_active Expired
- 1979-08-31 NL NL7906559A patent/NL7906559A/en not_active Application Discontinuation
- 1979-09-04 JP JP11346879A patent/JPS5549490A/en active Granted
- 1979-09-24 DE DE19792938524 patent/DE2938524A1/en active Granted
- 1979-09-28 IT IT26090/79A patent/IT1163718B/en active
- 1979-09-28 ES ES1979257023U patent/ES257023Y/en not_active Expired
- 1979-10-01 CH CH880979A patent/CH646227A5/en not_active IP Right Cessation
- 1979-10-01 SE SE7908122A patent/SE7908122L/en unknown
- 1979-10-01 FR FR7924379A patent/FR2443560A1/en active Granted
- 1979-10-01 BE BE0/197412A patent/BE879116A/en not_active IP Right Cessation
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4440246A (en) * | 1981-04-11 | 1984-04-03 | Christensen, Inc. | Cutting member for rotary drill bits |
| EP0149530A2 (en) * | 1984-01-16 | 1985-07-24 | CDP, Ltd. | Self sharpening drag bit assembly |
| EP0149530A3 (en) * | 1984-01-16 | 1986-02-05 | CDP, Ltd. | Self sharpening drag bit assembly |
| EP0151537A2 (en) * | 1984-01-31 | 1985-08-14 | Nl Industries Inc. | Improved drill bit and cutter therefor |
| GB2155083A (en) * | 1984-01-31 | 1985-09-18 | Nl Industries Inc | Improved drill bit and cutter therefor |
| EP0151537A3 (en) * | 1984-01-31 | 1986-05-28 | Nl Industries Inc. | Improved drill bit and cutter therefor |
| GB2181472A (en) * | 1985-08-22 | 1987-04-23 | Anderson Strathclyde Plc | Cutter tools and tip inserts therefor |
Also Published As
| Publication number | Publication date |
|---|---|
| NL7906559A (en) | 1980-04-08 |
| ZA794097B (en) | 1980-11-26 |
| SE7908122L (en) | 1980-04-03 |
| JPS6238517B2 (en) | 1987-08-18 |
| DE2938524C2 (en) | 1991-12-19 |
| BE879116A (en) | 1980-02-01 |
| GB2032979B (en) | 1982-09-08 |
| FR2443560B1 (en) | 1984-07-20 |
| JPS5549490A (en) | 1980-04-09 |
| IL58031A0 (en) | 1979-12-30 |
| DE2938524A1 (en) | 1980-04-10 |
| FR2443560A1 (en) | 1980-07-04 |
| IL58031A (en) | 1982-08-31 |
| ES257023Y (en) | 1982-04-16 |
| CH646227A5 (en) | 1984-11-15 |
| IT7926090A0 (en) | 1979-09-28 |
| IT1163718B (en) | 1987-04-08 |
| ES257023U (en) | 1981-10-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19930821 |