Matrix Drill Bits With Back Raked Cutting Elements

Abstract

A matrix drill bit and method of manufacturing a matrix bit having back raked cutting elements is disclosed. In one aspect, a matrix drill bit for well drilling includes a matrix bit body that has a front area in a direction of drilling and two or more diamond impregnated cutting blades protruding from the front area of the matrix bit body. The cutting blades each have a front external surface protruding from the front area of the matrix bit body and present a plurality of back raked downhole interface surfaces in the direction of drilling. The downhole interface surfaces span a leading face and a trailing face where the leading face extends to a first height and the trailing face extends to a second height and the first height is greater than the second height.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete and thorough understanding of the present embodiments and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features, and wherein:

FIG. 1 is a schematic drawing showing an isometric view of a matrix drill bit formed in accordance with teachings of the present disclosure;

FIG. 2 is a schematic drawing in section with portions broken away showing cutting elements of a matrix drill bit formed in accordance with teachings of the present disclosure;

FIGS. 3A and 3B are schematic drawings of a cutting element having a rounded cutting surface formed in accordance with teachings of the present disclosure; and

FIGS. 4A and 4B are schematic drawings of a cutting element having a peaked cutting surface formed in accordance with teachings of the present disclosure.

Claims

1. A matrix drill bit for well drilling comprising: a matrix bit body having a front area in a direction of drilling;two or more diamond impregnated cutting blades protruding from the front area of the matrix bit body; andeach cutting blade presenting a plurality of back raked downhole interface surfaces in the direction of drilling, each back raked downhole interface surface spanning a leading face and a trailing face, the leading face extending to a first height and the trailing face extending to a second height, the first height greater than the second height.

2. The matrix drill bit according to claim 1 wherein the at least one cutting blade comprises a diamond impregnated sintered cutting blade.

3. The matrix drill bit according to claim 1 wherein the at least one cutting blade comprises a diamond impregnated infiltrated cutting blade.

4. The matrix drill bit according to claim 1 comprising a plurality of the back raked downhole interface surfaces having a peaked configuration.

5. The matrix drill bit according to claim 1 comprising a plurality of the back raked downhole interface surfaces having a rounded configuration.

6. The matrix drill bit according to claim 1 comprising: a plurality of back raked downhole interface surfaces each having a peaked configuration; anda plurality of back raked downhole interface surfaces each cutting elements having a rounded configuration.

7. The matrix drill bit according to claim 6 comprising at least one of the cutting blades having a rounded downhole interface surface disposed adjacent and trailing a cutting element having a peaked downhole interface surface.

8. The matrix drill bit according to claim 1 comprising the back raked cutting element interface surface having a back rake angle between approximately ten degrees and approximately thirty degrees.

9. The matrix drill bit according to claim 1 comprising the difference in height between the leading face and the trailing face between approximately five millimeters and approximately twenty millimeters.

10. The matrix drill bit according to claim 1 comprising; at least one primary cutting blade protruding from the front area of the matrix bit body and extending radially from an approximate center of the front area of matrix bit body to an approximate gauge diameter of the matrix bit body; andat least one secondary blade protruding from the front area of the matrix bit body and extending radially from a selected radius of the matrix bit body to the approximate gauge diameter of the matrix bit body.

11. The matrix drill bit according to claim 1 further comprising a slot formed between each of the cutting blades configured to allow cutting materials to flow therethrough.

12. The matrix drill bit according to claim 11 comprising the slot having a width between five millimeters and thirty millimeters.

13. The matrix drill bit according to claim 11 further comprising at least one bridge element coupled to two of the cutting blades and spanning the slot therebetween.

14. The matrix drill bit according to claim 1 comprising the matrix bit body formed from a composite of tungsten carbide and diamond impregnated segments.

15. The matrix drill bit according to claim 1 comprising the back raked downhole interface surfaces configured to shear soft formation and to grind a hard formation.

16. The matrix drill bit according to claim 1 wherein the cutting blades each comprise one or more thermally stable polycrystalline cutting elements formed therein.

17. A drill bit having a matrix bit body comprising: a plurality of diamond impregnated cutting elements disposed at selected locations on exterior portions of the matrix bit body; andeach cutting element presenting a back raked downhole interface surface in the direction of drilling, the downhole interface surface spanning a leading face and a trailing face, the leading face extending to a first height and the trailing face extending to a second height, the first height greater than the second height.

18. The matrix drill bit according to claim 17 wherein the plurality of cutting elements comprise diamond impregnated sintered cutting elements.

19. The matrix drill bit according to claim 17 wherein the plurality of cutting elements comprise diamond impregnated infiltrated cutting elements.

20. The matrix drill bit according to claim 17 comprising the back raked downhole interface surface configured to shear a soft formation and to grind a hard formation.

21. The matrix drill bit according to claim 17 comprising a plurality of the back raked cutting element interface surface having a peaked configuration.

22. The matrix drill bit according to claim 17 comprising a plurality of the back raked cutting element interface surfaces having a rounded configuration.

23. The matrix drill bit according to claim 17 comprising the back raked cutting element interface surface having a back rake angle between approximately ten degrees and approximately thirty degrees.

24. The matrix drill bit according to claim 17 comprising the difference in height between the leading face and the trailing face between approximately five millimeters and approximately twenty millimeters.

25. A method of making a matrix drill bit comprising: forming a plurality of impregnated diamond cutting blades each presenting a back raked downhole interface surface spanning a leading face and a trailing face, the leading face extending to a first height and the trailing face extending to a second height, the first height greater than the second height.casting in each of the plurality of cutting elements at selected locations on exterior portions of the matrix bit body presenting the downhole interface surfaces of the cutting elements in the direction of drilling.