EARTH BORING DRILL BITS WITH USING OPPOSED KERFING FOR CUTTERS
A drill bit configured having eight blades thereon with secondary cutters on four blades using opposed kerfing for the secondary cutters located on four of the blades.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/084,811, filed Jul. 30, 2008, the disclosure of which is incorporated herein in its entirety.
TECHNICAL FIELDThe present invention relates generally to drilling a subterranean borehole and, more specifically, to drill bits using opposed kerfing profiles for cutters.
BACKGROUND OF THE INVENTIONState of the Art: The drilling of wells for any reason, such as oil and gas production, geothermal production, water production, etc. conventionally may employ drill bits using diamond cutters located on a variable number of blades of the drill bit. Typically, drill bits having a fewer number of blades on the drill bit tend to cut faster and have bigger junk slots for the removal of cutting from the well bore than drill bits having more blades. However, when the number of blades on the drill bit and the number of cutters on the drill bit are increased, the loading on each cutter can be reduced, thereby improving cutter life and drill bit life during drilling a well bore.
It would be desirable to reduce the number of blades on a drill bit to increase the rate of penetration of the drill bit in comparison to that of a drill bit having more blades thereon, while reducing individual cutter loading to increase cutter life and drill bit life.
BRIEF SUMMARY OF THE INVENTIONA drill bit configured having multiple blades thereon with secondary cutters on a reduced number of blades (secondary blades) of the drill bit, using opposed kerfing for the secondary cutters located on the secondary blades.
The features and advantages of the present invention will become apparent to those of ordinary skill in the art through consideration of the ensuing description, the accompanying drawings, and the appended claims.
In the drawings, which illustrate what is currently considered to be the best mode for carrying out the invention:
Also, each of blades 22 may include a gage region 25 that is configured to define the outermost radius of the drill bit 12 and, thus the radius of the wall surface of a borehole drilled thereby. Gage regions 25 comprise longitudinally upward (as the casing bit 12 is oriented during use) extensions of blades 22, extending from nose portion 20 and may have wear-resistant inserts or coatings, such as cutting elements in the form of gage trimmers of natural or synthetic diamond, or hardfacing material, on radially outer surfaces thereof as known in the art to inhibit excessive wear thereto.
Drill bit 12 is also provided with pockets 34 in four of the blades 22, which may be configured to receive abrasive cutting elements 36 of similar type as those of the first type of cutting elements 32, cutting elements 36 being located in a second row of cutting elements located behind the cutting elements 32 of the first row on four of the eight blades of the drill bit 12. It is also contemplated that abrasive cutting elements 36 may comprise, for example, a carbide material other than tungsten (W) carbide, such as a Ti, Mo, Nb, V, Hf, Ta, Cr, Zr, Al, and Si carbide, or a ceramic. Abrasive cutting elements 36 may be secured within pockets 34 by welding, brazing or as otherwise known in the art.
As depicted in
Also as shown in
Superabrasive cutting elements 32 and superabrasive cutting elements 36 are respectively dimensioned and configured, in combination with the respective depths and locations of pockets 30 and 34, to provide cutting elements 36 with the same relative exposure as cutting elements 32, although cutting elements 36 may have a greater or lesser relative exposure than superabrasive cutting elements 32, if desired. As used herein, the term “exposure” of a cutting element generally indicates its distance of protrusion above a portion of a drill bit, for example, a blade surface or the profile thereof, to which it is mounted. However, in reference specifically to the present invention, “relative exposure” is used to denote a difference in exposure between a cutting element 32 of the one type and a cutting element 36 of the same type. More specifically, the term “relative exposure” may also be used to denote a difference in exposure between one cutting element 32 and another cutting element 36, which are proximately located on drill bit 12 at similar radial positions relative to a centerline L (see
In the embodiment depicted in
Referring to
By way of illustration of the foregoing,
By way of illustration of the foregoing,
Although the foregoing description contains many specifics, these should not be construed as limiting the scope of the present invention, but merely as providing illustrations of some exemplary embodiments. Similarly, other embodiments of the invention may be devised that do not depart from the spirit or scope of the present invention. Features from different embodiments may be employed in combination. The scope of the invention is, therefore, indicated and limited only by the appended claims and their legal equivalents, rather than by the foregoing description. All additions, deletions, and modifications to the invention, as disclosed herein, which fall within the meaning and scope of the claims, are to be embraced thereby.
Claims
1. A drill bit for drilling a subterranean formation comprising:
- a bit body having a face, a plurality of primary blades, and a plurality of secondary blades, each secondary blade of the plurality of secondary blades located between two blades of the plurality of primary blades;
- a first plurality of cutting elements disposed on a first blade of the plurality of primary blades in radial positions thereon;
- a second plurality of cutting elements disposed on the first blade of the plurality of primary blades, the second plurality of cutting elements being disposed in radial position behind the first plurality of cutting elements being located in radial position at one of substantially between the cutting elements disposed in front thereof and substantially behind the cutting elements disposed in front thereof;
- a third plurality of cutting elements disposed in radial positions on a first blade of the plurality of secondary blades, the first blade of the plurality of secondary blades located adjacent the first blade;
- a fourth plurality of cutting elements disposed on a second primary blade of the plurality of blades; and
- a fifth plurality of cutting elements disposed on the second blade of the plurality of primary blades in radial positions thereon, the fifth plurality of cutting elements being disposed in radial positions behind the fourth plurality of cutting elements being located substantially between the cutting elements disposed in front thereof, at least some of the fifth plurality of cutting elements having substantially the same radial positions on the drill bit as the radial positions of the first plurality of cutting elements on the first blade of the plurality of primary blades.
2. The drill bit of claim 1, wherein the drill bit includes one of an even number of blades thereon and an odd number of blades thereon.
3. The drill bit of claim 2, wherein a plurality of cutting elements of the at least one type and a plurality of cutting elements of at least another, different type are disposed on each blade.
4. The drill bit of claim 1, wherein the first, second, third, fourth, and fifth cutting elements are disposed in pockets formed in the blades.
5. The drill bit of claim 1, wherein the first, second, third, fourth, and fifth cutting elements comprise one of superabrasive cutting elements and abrasive cutting elements.
6. The drill bit of claim 5, wherein the superabrasive cutting elements comprise PDC cutting elements and the abrasive cutting elements comprise tungsten carbide cutting elements.
7. The drill bit of claim 1, wherein a central portion of an outer profile of the face is configured as an inverted cone and is surrounded by a nose.
8. The drill bit of claim 1, wherein cutting elements are selected from the group consisting of a PDC cutting element, a thermally stable diamond cutting element, and a natural diamond cutting element.
9. The drill bit of claim 1, wherein the cutting elements are selected from the group consisting of a tungsten carbide cutting element, another metal carbide cutting element and a ceramic.
10. The drill bit of claim 1, wherein the second primary blade of the plurality of primary blades is located approximately 180° circumferentially from the first blade of the plurality of primary blades.
11. A drill bit for drilling a subterranean formation comprising:
- a bit body having a face at a leading end thereof and a plurality of blades;
- a first plurality of cutting elements disposed on a first blade of the plurality of blades in radial positions thereon;
- a second plurality of cutting elements disposed on the first blade of the plurality of blades, the second plurality of cutting elements being disposed in radial position behind the first plurality of cutting elements being located in radial position at one of substantially between the cutting elements disposed in front thereof and substantially behind the cutting elements disposed in front thereof;
- a third plurality of cutting elements disposed in radial positions on a second blade of the plurality of blades, the second blade located adjacent the first blade;
- a fourth plurality of cutting elements disposed on a third blade located approximately 180° circumferentially from the first blade of the plurality of blades in radial positions thereon; and
- a fifth plurality of cutting elements disposed on the third blade of the plurality of blades in radial positions thereon, the fifth plurality of cutting elements being disposed in radial positions behind the fourth plurality of cutting elements being located substantially between the cutting elements disposed in front thereof, at least some of the fifth plurality of cutting elements having substantially the same radial positions on the drill bit as the radial positions of the first plurality of cutting elements on the first blade.
12. The drill bit of claim 11, wherein the drill bit includes one of an even number of blades thereon and an odd number of blades thereon.
13. The drill bit of claim 12, wherein a plurality of cutting elements of the at least one type and a plurality of cutting elements of at least another, different type are disposed on each blade.
14. A drill bit for drilling a subterranean formation comprising:
- a bit body having an even number of blades;
- a first plurality of cutting elements disposed on a first blade of the plurality of blades in radial positions thereon;
- a second plurality of cutting elements disposed on the first blade of the plurality of blades, the second plurality of cutting elements being disposed in radial position behind the first plurality of cutting elements being located in radial position substantially behind the cutting elements disposed in front thereof;
- a third plurality of cutting elements disposed in radial positions on a second blade of the plurality of blades, the second blade located adjacent the first blade;
- a fourth plurality of cutting elements disposed on a third blade located approximately 180° circumferentially from the first blade of the plurality of blades in radial positions thereon; and
- a fifth plurality of cutting elements disposed on the third blade of the plurality of blades in radial positions thereon, the fifth plurality of cutting elements being disposed in radial positions behind the fourth plurality of cutting elements being located substantially behind the cutting elements disposed in front thereof, at least some of the fifth plurality of cutting elements having substantially the same radial positions on the drill bit as the radial positions of the first plurality of cutting elements on the first blade.
15. The drill bit of claim 14, wherein the first, second, third, fourth, and fifth cutting elements are disposed in pockets formed in the blades.
16. The drill bit of claim 14, wherein the first, second, third, fourth, and fifth cutting elements comprise one of superabrasive cutting elements and abrasive cutting elements.
17. A drill bit for drilling a subterranean formation comprising:
- a bit body having an even number of blades;
- a first plurality of cutting elements disposed on a first blade of the plurality of blades in radial positions thereon;
- a second plurality of cutting elements disposed on the first blade of the plurality of blades, the second plurality of cutting elements being disposed in one of a radial position including one of substantially behind the cutting elements disposed in front thereof and substantially behind the cutting elements disposed in front thereof;
- a third plurality of cutting elements disposed in radial positions on a second blade of the plurality of blades, the second blade located adjacent the first blade;
- a fourth plurality of cutting elements disposed on a third blade located less than approximately 180° circumferentially from the first blade of the plurality of blades in radial positions thereon; and
- a fifth plurality of cutting elements disposed on the third blade of the plurality of blades in radial positions thereon, the fifth plurality of cutting elements being disposed in radial positions including one of substantially behind the cutting elements disposed in front thereof and substantially behind the cutting elements disposed in front thereof, at least some of the fifth plurality of cutting elements having substantially the same radial positions on the drill bit as the radial positions of the first plurality of cutting elements on the first blade.
Type: Application
Filed: Jul 29, 2009
Publication Date: Feb 4, 2010
Inventor: Thorsten Schwefe (Spring, TX)
Application Number: 12/511,233
International Classification: E21B 10/43 (20060101); E21B 10/55 (20060101);