CA2429862C - Drill bit - Google Patents
Drill bit Download PDFInfo
- Publication number
- CA2429862C CA2429862C CA002429862A CA2429862A CA2429862C CA 2429862 C CA2429862 C CA 2429862C CA 002429862 A CA002429862 A CA 002429862A CA 2429862 A CA2429862 A CA 2429862A CA 2429862 C CA2429862 C CA 2429862C
- Authority
- CA
- Canada
- Prior art keywords
- drill bit
- injection means
- fluid injection
- borehole
- primary
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
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
- E21B10/36—Percussion drill bits
- E21B10/38—Percussion drill bits characterised by conduits or nozzles for drilling fluids
Abstract
A drill hit for drilling a borehole into an earth formation is provided. The drill bit has a central longitudinal axis and a bottom surface facing the borehole bottom during drilling with the drill bit, and comprises primary fluid injection means (10) arranged at the bottom surface and located at a selected radial distance from the central longitudinal axis, the primary flu id injection means being arranged to eject a primary stream of fluid into the borehole, the primary stream having a component in a transverse plane of the drill bit, directed from the fluid injection means to the central longitudin al axis.
Description
DRILL BIT
The present invention relates to a drill bit for drilling a borehole into an earth formation. Drill bits generally operate on the basis of a rotational action of cutting members against the borehole bottom. In many of the harder rock formations the rate of penetration of such rotary drill bits is relatively low. In hard rock formations improved results have been obtained with percussion drilling systems which operate on the basis of a combined rotational and hammering action of the bit against the borehole bottom. Such percussion bits gen~rally have cutting members (for, example of relatively large hemispherical shape) which predominantly have a downward crushing action. In view thereof drill cuttings of relatively small size are produced by the drill bit, which cuttings in a wet environment have an increased tendency of clogging of the bottom surface of the drill bit and the borehole bottom. Once the bottom surface of the drill bit has become clogged by a mass of wet drill cuttings (also referred to as bit balling) th.e drilling efficiency is significantly reduced. -It is therefore an object of some embodiments to provide a drill bit which has a reduced tendency of clogging of the bottom surface with drill cuttings.
In accordance with the invention there is provided a drill bit for drilling a borehole into an earth formation, the drill bit having a central longitudinal axis and a bottom surface facing the borehole bottom during drilling with the drill bit, the drill bit comprising primary fluid injection means arranged at the bottom surface and located at a selected radial distance from the central longitudinal axis, the primary fluid injection means being arranged to eject a primary stream of fluid into the borehole, the primary stream having a component in a transverse plane of the drill bit, directed from the fluid injection means to the central longitudinal axis.
The direction of the primary fluid injection means is such that said component of the primary stream is directed towards the central part of the bottom surface.
As a result the central part of the bottom surface, which is most prone to clogging (e.g. due to the relatively low rotational velocity), is cleaned from drill cuttings.
Suitably the drill bit further comprises secondary fluid injection means arranged at the bottom surface and spaced from the primary fluid injection means, the secondary fluid injection means being arranged to eject a secondary stream of fluid into the borehole, the secondary stream having a component in said transverse plane, directed substantially opposite the direction of said component of the primary stream of fluid.
In this manner the streams flow in a cross-flow mode thereby ensuring that all parts of the bottom surface of the bit are adequately cleaned.
It is furthermore achieved that the borehole bottom is adequately cleaned from drill cuttings.
The invention will described hereinafter in more detail and by way of example, with reference to the accompanying drawings in which:
Fig. 1 schematically shows a side view of an embodiment of the drill bit according to the invention;
Fig. 2 schematically shows a bottom view of the drill bit of Fig. 1 (seen in the direction 2-2);
Fig. 3 schematically shows a longitudinal section along lines 3-3 in Fig. 2; and Fig. 4 schematically shows a longitudinal section of a lower end part of an alternative drill bit according to the invention.
In the Figures like reference signs relate to like components.
Referring to Figs. 1 and 2 there is shown a percussion drill bit 1 for drilling of a borehole (not shown) into an earth formation, the drill bit 1 having a central longitudinal axis 2 and a bottom surface 3 facing the borehole bottom during drilling with the drill bit 1.
A connector 4 for connecting the drill bit 1 to a drill string (not shown) is arranged at the upper end of the drill bit 1, and a plurality of drilling fluid channels extend in longitudinal direction in the form of recesses 5 formed in the gauge surface 5a of the drill bit 1. The bottom surface 3 is provided with a plurality of mutually spaced hemispherical cutting members 6.
Referring further to Fig. 3, the drill bit 1 is internally provided with a fluid channel 8 which is in fluid communication with a drilling fluid conduit (not shown) of the drill string, which channel 8 is provided with a primary fluid injection means in the form of nozzle 10 located at a radial distance from the central longitudinal axis 2 and debouching at the bottom surface 3. The primary nozzle 10 has a bent fluid passage 12 so as to eject a primary stream 13 of fluid into the borehole in a direction 14 (Fig. 3) having a component in a transverse plane (not shown) of the drill bit 1, directed from the nozzle 10 to the central longitudinal axis 2.
The drill bit is further provided with two mutually spaced secondary fluid injection means in the form of nozzles 18, 19 (Fig. 2) arranged at a radial distance from the central longitudinal axis 2 and debouching at the bottom surface 3. Each secondary nozzle 18, 19 is arranged in a respective fluid channel (not shown) of the drill bit which is in fluid communication with the drilling fluid conduit of the drill string. Further, each secondary nozzle 18, 19 is directed so as to inject a secondary stream 20, 21 of fluid into the borehole in a direction having a component in said transverse plane, in a direction opposite the direction of said component of the primary stream of fluid.
In Fig. 4 is shown an alternative nozzle arrangement with nozzle 22 which can be applied instead of the bent nozzles 10, 18, 19 referred to above. The alternative nozzle 22 has a straight fluid passage 24 and is arranged in a bent fluid channel 26 so as to eject, during normal use, a stream of fluid into the borehole in the desired direction (for example direction 14).
During normal operation, the drill bit lis connected to the lower end of the drill string by means of connector .4. The drill string is lowered in the borehole and operated in a percussion drilling mode whereby the bit is simultaneously rotated about central longitudinal axis 2 and translated so as to provide a hammering action on the borehole bottom. Due to the hammering action of the hemispherical cutting members 6 against the borehole bottom, drill cuttings of relatively small size are produced. Therefore, there will be an increased tendency of clogging of the bottom surface 3 with wet drill cuttings, when compared to drill bits which purely rely on a rotational action and not on a hammering action.
Simultaneously with the rotational and hammering movement of the drill bitl, drilling fluid is pumped through the drill string and from there into the respective fluid channels and nozzles 10, 18, 19. As a result a primary fluid stream 13 and secondary fluid streams 20, 21 are ejected from the respective nozzles 10, 18, 19 into the space between the bottom surface 3 and the borehole bottom. Due to the directional arrangement of the nozzles 10, 18, 19, the streams 13, 18, 19 flow in a cross-flow mode whereby stream 13 flows towards the centre of the end surface 3, and streams 18, 5 19 flow in opposite direction to the stream 13 at both sides thereof. It is thereby achieved that the central part of the end surface 3 is predominantly cleaned from drill cuttings by the stream 13, and that the outer area of the bottom surface 13 is predominantly cleaned from drill cuttings by the streams 18, 19. Furthermore, the streams 13, 18, 19 also serve to efficiently clean the borehole bottom from drill cuttings.
Normal operation of the drill bit with the alternative nozzle arrangement shown in Fig. 4 is similar to normal operation of the drill bit shown in Fig. 3.
The present invention relates to a drill bit for drilling a borehole into an earth formation. Drill bits generally operate on the basis of a rotational action of cutting members against the borehole bottom. In many of the harder rock formations the rate of penetration of such rotary drill bits is relatively low. In hard rock formations improved results have been obtained with percussion drilling systems which operate on the basis of a combined rotational and hammering action of the bit against the borehole bottom. Such percussion bits gen~rally have cutting members (for, example of relatively large hemispherical shape) which predominantly have a downward crushing action. In view thereof drill cuttings of relatively small size are produced by the drill bit, which cuttings in a wet environment have an increased tendency of clogging of the bottom surface of the drill bit and the borehole bottom. Once the bottom surface of the drill bit has become clogged by a mass of wet drill cuttings (also referred to as bit balling) th.e drilling efficiency is significantly reduced. -It is therefore an object of some embodiments to provide a drill bit which has a reduced tendency of clogging of the bottom surface with drill cuttings.
In accordance with the invention there is provided a drill bit for drilling a borehole into an earth formation, the drill bit having a central longitudinal axis and a bottom surface facing the borehole bottom during drilling with the drill bit, the drill bit comprising primary fluid injection means arranged at the bottom surface and located at a selected radial distance from the central longitudinal axis, the primary fluid injection means being arranged to eject a primary stream of fluid into the borehole, the primary stream having a component in a transverse plane of the drill bit, directed from the fluid injection means to the central longitudinal axis.
The direction of the primary fluid injection means is such that said component of the primary stream is directed towards the central part of the bottom surface.
As a result the central part of the bottom surface, which is most prone to clogging (e.g. due to the relatively low rotational velocity), is cleaned from drill cuttings.
Suitably the drill bit further comprises secondary fluid injection means arranged at the bottom surface and spaced from the primary fluid injection means, the secondary fluid injection means being arranged to eject a secondary stream of fluid into the borehole, the secondary stream having a component in said transverse plane, directed substantially opposite the direction of said component of the primary stream of fluid.
In this manner the streams flow in a cross-flow mode thereby ensuring that all parts of the bottom surface of the bit are adequately cleaned.
It is furthermore achieved that the borehole bottom is adequately cleaned from drill cuttings.
The invention will described hereinafter in more detail and by way of example, with reference to the accompanying drawings in which:
Fig. 1 schematically shows a side view of an embodiment of the drill bit according to the invention;
Fig. 2 schematically shows a bottom view of the drill bit of Fig. 1 (seen in the direction 2-2);
Fig. 3 schematically shows a longitudinal section along lines 3-3 in Fig. 2; and Fig. 4 schematically shows a longitudinal section of a lower end part of an alternative drill bit according to the invention.
In the Figures like reference signs relate to like components.
Referring to Figs. 1 and 2 there is shown a percussion drill bit 1 for drilling of a borehole (not shown) into an earth formation, the drill bit 1 having a central longitudinal axis 2 and a bottom surface 3 facing the borehole bottom during drilling with the drill bit 1.
A connector 4 for connecting the drill bit 1 to a drill string (not shown) is arranged at the upper end of the drill bit 1, and a plurality of drilling fluid channels extend in longitudinal direction in the form of recesses 5 formed in the gauge surface 5a of the drill bit 1. The bottom surface 3 is provided with a plurality of mutually spaced hemispherical cutting members 6.
Referring further to Fig. 3, the drill bit 1 is internally provided with a fluid channel 8 which is in fluid communication with a drilling fluid conduit (not shown) of the drill string, which channel 8 is provided with a primary fluid injection means in the form of nozzle 10 located at a radial distance from the central longitudinal axis 2 and debouching at the bottom surface 3. The primary nozzle 10 has a bent fluid passage 12 so as to eject a primary stream 13 of fluid into the borehole in a direction 14 (Fig. 3) having a component in a transverse plane (not shown) of the drill bit 1, directed from the nozzle 10 to the central longitudinal axis 2.
The drill bit is further provided with two mutually spaced secondary fluid injection means in the form of nozzles 18, 19 (Fig. 2) arranged at a radial distance from the central longitudinal axis 2 and debouching at the bottom surface 3. Each secondary nozzle 18, 19 is arranged in a respective fluid channel (not shown) of the drill bit which is in fluid communication with the drilling fluid conduit of the drill string. Further, each secondary nozzle 18, 19 is directed so as to inject a secondary stream 20, 21 of fluid into the borehole in a direction having a component in said transverse plane, in a direction opposite the direction of said component of the primary stream of fluid.
In Fig. 4 is shown an alternative nozzle arrangement with nozzle 22 which can be applied instead of the bent nozzles 10, 18, 19 referred to above. The alternative nozzle 22 has a straight fluid passage 24 and is arranged in a bent fluid channel 26 so as to eject, during normal use, a stream of fluid into the borehole in the desired direction (for example direction 14).
During normal operation, the drill bit lis connected to the lower end of the drill string by means of connector .4. The drill string is lowered in the borehole and operated in a percussion drilling mode whereby the bit is simultaneously rotated about central longitudinal axis 2 and translated so as to provide a hammering action on the borehole bottom. Due to the hammering action of the hemispherical cutting members 6 against the borehole bottom, drill cuttings of relatively small size are produced. Therefore, there will be an increased tendency of clogging of the bottom surface 3 with wet drill cuttings, when compared to drill bits which purely rely on a rotational action and not on a hammering action.
Simultaneously with the rotational and hammering movement of the drill bitl, drilling fluid is pumped through the drill string and from there into the respective fluid channels and nozzles 10, 18, 19. As a result a primary fluid stream 13 and secondary fluid streams 20, 21 are ejected from the respective nozzles 10, 18, 19 into the space between the bottom surface 3 and the borehole bottom. Due to the directional arrangement of the nozzles 10, 18, 19, the streams 13, 18, 19 flow in a cross-flow mode whereby stream 13 flows towards the centre of the end surface 3, and streams 18, 5 19 flow in opposite direction to the stream 13 at both sides thereof. It is thereby achieved that the central part of the end surface 3 is predominantly cleaned from drill cuttings by the stream 13, and that the outer area of the bottom surface 13 is predominantly cleaned from drill cuttings by the streams 18, 19. Furthermore, the streams 13, 18, 19 also serve to efficiently clean the borehole bottom from drill cuttings.
Normal operation of the drill bit with the alternative nozzle arrangement shown in Fig. 4 is similar to normal operation of the drill bit shown in Fig. 3.
Claims (6)
1. A drill bit for drilling a borehole into an earth formation, the drill bit having a central longitudinal axis and a bottom surface facing the borehole bottom during drilling with the drill bit, the drill bit comprising primary fluid injection means arranged at the bottom surface and located at a selected radial distance from the central longitudinal axis, the primary fluid injection means being arranged to eject a primary stream of fluid into the borehole, the primary stream having a component in a transverse plane of the drill bit, directed from the fluid injection means to the central longitudinal axis, the drill bit further comprising secondary fluid injection means arranged at the bottom surface and spaced from the primary fluid injection means, the secondary fluid injection means being arranged to eject a secondary stream of fluid into the borehole, the secondary stream having a component in said transverse plane, directed substantially opposite the direction of said component of the primary stream of fluid in a cross-flow mode.
2. The drill bit of claim 1, wherein the drill bit is provided with a plurality of mutually spaced said secondary fluid injection means.
3. The drill bit of claim 2, wherein the plurality of mutually spaced secondary fluid injection means are arranged to eject the secondary stream on both sides of the primary stream in operation.
4. The drill bit of any one of claims 1-3, wherein in operation there is essentially one primary stream.
5. The drill bit of any one of claims 1-4, wherein each fluid injection means includes a fluid injection nozzle.
6. The drill bit of any of claims 1-5, wherein the drill bit is a percussion drill bit provided with a plurality of mutually spaced cutting elements arranged at said bottom surface.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP00204198 | 2000-11-27 | ||
| EP00204198.6 | 2000-11-27 | ||
| PCT/EP2001/014137 WO2002042597A1 (en) | 2000-11-27 | 2001-11-27 | Drill bit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2429862A1 CA2429862A1 (en) | 2002-05-30 |
| CA2429862C true CA2429862C (en) | 2009-10-13 |
Family
ID=8172334
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002429862A Expired - Fee Related CA2429862C (en) | 2000-11-27 | 2001-11-27 | Drill bit |
Country Status (10)
| Country | Link |
|---|---|
| US (1) | US6971458B2 (en) |
| EP (1) | EP1337734B1 (en) |
| CN (1) | CN1280516C (en) |
| AT (1) | ATE504717T1 (en) |
| AU (2) | AU2002221922B2 (en) |
| CA (1) | CA2429862C (en) |
| DE (1) | DE60144388D1 (en) |
| EA (1) | EA004281B1 (en) |
| NO (1) | NO20032353L (en) |
| WO (1) | WO2002042597A1 (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7040423B2 (en) * | 2004-02-26 | 2006-05-09 | Smith International, Inc. | Nozzle bore for high flow rates |
| SE530135C2 (en) * | 2004-09-21 | 2008-03-11 | Sandvik Intellectual Property | Rock drill bit adapted for striking drilling |
| SE530602C2 (en) * | 2004-11-17 | 2008-07-15 | Sandvik Intellectual Property | Rock drill bit for striking drilling |
| US7481284B2 (en) * | 2005-01-25 | 2009-01-27 | Baker Hughes Incorporated | Converging diverging nozzle for earth-boring drill bits, method of substantially bifurcating a drilling fluid flowing therethrough, and drill bits so equipped |
| US7694608B2 (en) * | 2005-12-20 | 2010-04-13 | Smith International, Inc. | Method of manufacturing a matrix body drill bit |
| US7527110B2 (en) * | 2006-10-13 | 2009-05-05 | Hall David R | Percussive drill bit |
| US20090184564A1 (en) * | 2008-01-22 | 2009-07-23 | The William J. Brady Loving Trust | Pcd percussion drill bit |
| FI20086206A0 (en) * | 2008-12-17 | 2008-12-17 | Atlas Copco Rotex Ab Oy | Method and equipment for submersible drilling |
| US20100193253A1 (en) * | 2009-01-30 | 2010-08-05 | Massey Alan J | Earth-boring tools and bodies of such tools including nozzle recesses, and methods of forming same |
| EP2369127A1 (en) * | 2010-03-09 | 2011-09-28 | Sandvik Intellectual Property AB | A rock drill bit, a drilling assembly and a method for percussive rock drilling |
| CN103225480B (en) * | 2013-03-28 | 2015-06-17 | 乐山天威机械制造有限公司 | Heavy hammer for excavating rock formation and welding processing method |
| US10487589B2 (en) | 2016-01-20 | 2019-11-26 | Baker Hughes, A Ge Company, Llc | Earth-boring tools, depth-of-cut limiters, and methods of forming or servicing a wellbore |
| US10508323B2 (en) | 2016-01-20 | 2019-12-17 | Baker Hughes, A Ge Company, Llc | Method and apparatus for securing bodies using shape memory materials |
| US10280479B2 (en) | 2016-01-20 | 2019-05-07 | Baker Hughes, A Ge Company, Llc | Earth-boring tools and methods for forming earth-boring tools using shape memory materials |
| US10053916B2 (en) | 2016-01-20 | 2018-08-21 | Baker Hughes Incorporated | Nozzle assemblies including shape memory materials for earth-boring tools and related methods |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3688852A (en) * | 1970-08-24 | 1972-09-05 | Gulf Research Development Co | Spiral coil nozzle holder |
| US4494618A (en) * | 1982-09-30 | 1985-01-22 | Strata Bit Corporation | Drill bit with self cleaning nozzle |
| US4730682A (en) * | 1985-12-23 | 1988-03-15 | Ingersoll-Rand Company | Erosion resistant rock drill bit |
| US4687066A (en) * | 1986-01-15 | 1987-08-18 | Varel Manufacturing Company | Rock bit circulation nozzle |
| US4819746A (en) * | 1987-01-13 | 1989-04-11 | Minroc Technical Promotions Ltd. | Reverse circulation down-the-hole hammer drill and bit therefor |
| US6089336A (en) * | 1995-10-10 | 2000-07-18 | Camco International (Uk) Limited | Rotary drill bits |
| US5794725A (en) * | 1996-04-12 | 1998-08-18 | Baker Hughes Incorporated | Drill bits with enhanced hydraulic flow characteristics |
| US5803187A (en) * | 1996-08-23 | 1998-09-08 | Javins; Brooks H. | Rotary-percussion drill apparatus and method |
-
2001
- 2001-11-27 CA CA002429862A patent/CA2429862C/en not_active Expired - Fee Related
- 2001-11-27 CN CNB018194842A patent/CN1280516C/en not_active Expired - Fee Related
- 2001-11-27 EP EP01997613A patent/EP1337734B1/en not_active Expired - Lifetime
- 2001-11-27 WO PCT/EP2001/014137 patent/WO2002042597A1/en not_active Application Discontinuation
- 2001-11-27 US US10/432,698 patent/US6971458B2/en not_active Expired - Lifetime
- 2001-11-27 AU AU2002221922A patent/AU2002221922B2/en not_active Ceased
- 2001-11-27 AU AU2192202A patent/AU2192202A/en active Pending
- 2001-11-27 EA EA200300608A patent/EA004281B1/en not_active IP Right Cessation
- 2001-11-27 DE DE60144388T patent/DE60144388D1/en not_active Expired - Lifetime
- 2001-11-27 AT AT01997613T patent/ATE504717T1/en not_active IP Right Cessation
-
2003
- 2003-05-26 NO NO20032353A patent/NO20032353L/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| US6971458B2 (en) | 2005-12-06 |
| CN1280516C (en) | 2006-10-18 |
| US20040069540A1 (en) | 2004-04-15 |
| EA004281B1 (en) | 2004-02-26 |
| AU2002221922B2 (en) | 2006-08-17 |
| CN1476511A (en) | 2004-02-18 |
| CA2429862A1 (en) | 2002-05-30 |
| EP1337734B1 (en) | 2011-04-06 |
| ATE504717T1 (en) | 2011-04-15 |
| WO2002042597A1 (en) | 2002-05-30 |
| EP1337734A1 (en) | 2003-08-27 |
| NO20032353D0 (en) | 2003-05-26 |
| NO20032353L (en) | 2003-07-25 |
| EA200300608A1 (en) | 2003-10-30 |
| DE60144388D1 (en) | 2011-05-19 |
| AU2192202A (en) | 2002-06-03 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20131127 |