Cutting element attached to downhole fixed bladed bit at a positive rake angle

Patent metadata

Field	Value
Publication number	US-9366089-B2
Application number	US-201314065119-A
Country	US
Kind code	B2
Filing date	Oct 28, 2013
Priority date	Aug 11, 2006
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

In one aspect of the present invention, a downhole fixed bladed bit comprises a working surface comprising a plurality of blades converging at a center of the working surface and diverging towards a gauge of the bit, at least on blade comprising a cutting element comprising a superhard material bonded to a cemented metal carbide substrate at a non-planer interface, the cutting element being positioned at a positive rake angle, and the superhard material comprising a substantially conical geometry with an apex comprising a curvature.

First claim

What is claimed:

1. A downhole cutting tool for drilling a wellbore, comprising:
a tool body;
a plurality of blades extending from the tool body, at least one of the plurality of blades extending from adjacent a center of the face of the tool body to a gauge portion;
an attachment end opposite the plurality of blades, the attachment end being coaxial with the tool body; and
a plurality of cutting elements disposed on the plurality of blades, a first cutting element on a first blade, the first cutting element comprising a polycrystalline diamond material disposed on a carbide substrate, the polycrystalline diamond material extending away from the carbide substrate to terminate in a substantially pointed geometry opposite the substrate, the first cutting element having a central axis extending therethrough, the first cutting element being oriented to form a positive rake angle ranging from 15 to 20 degrees between the central axis and a vertical line perpendicular to a surface to be engaged by the first cutting element.

2. The downhole cutting tool of claim 1 , wherein the substantially pointed geometry comprises a side wall that tangentially joins an apex having a radius of curvature.

3. The downhole cutting tool of claim 2 , wherein the side wall forms an included angle, the included angle being at least twice that of the positive rake angle.

4. The downhole cutting tool of claim 2 , wherein the first cutting element is positioned to indent at the positive rake angle, while a leading portion of the side wall is positioned at a negative rake angle relative to the vertical line.

5. The downhole cutting tool of claim 1 , wherein the first cutting element is positioned on a flank of one of the plurality of blades.

6. The downhole cutting tool of claim 1 , wherein the first cutting element is positioned on a gauge of one of the plurality of blades the first blade.

7. The downhole cutting tool of claim 2 , wherein the radius of curvature is less than 0.120 inches.

8. The downhole cutting tool of claim 2 , wherein the curvature is defined by a portion of an ellipse, a parabola, a hyperbola, a catenary, or a parametric spline.

9. The downhole cutting tool of claim 1 , wherein the downhole cutting tool is a fixed cutter drill bit having the plurality of blades extending from a bit body.

10. A downhole cutting tool for drilling a wellbore, comprising:
a tool body;
a plurality of radially extending blades extending from the tool body, at least one of the plurality of radially extending blades extending from adjacent a center of the face of the tool body to a gauge portion; and
a plurality of cutting elements disposed on the plurality of blades, a first cutting element comprising a polycrystalline diamond material disposed on a carbide substrate, the polycrystalline diamond material having a side wall extending away from the carbide substrate to terminate in a substantially pointed geometry opposite the substrate, the first cutting element being oriented such that a leading portion of the side wall of the first cutting element forms a negative rake angle with respect to a vertical line, and such that the central axis of the first cutting element forms a positive rake angle with respect to the vertical line.

11. The downhole cutting tool of claim 10 , wherein the positive rake angle ranges from 15 to 20.

12. The downhole cutting tool of claim 10 , wherein the side wall tangentially joins an apex having a radius of curvature.

13. The downhole cutting tool of claim 10 , wherein the side wall forms an included angle, the included angle being at least twice that of the positive rake angle.

14. The downhole cutting tool of claim 10 , wherein the first cutting element is positioned on a flank of one of the plurality of radially extending blades.

15. The downhole cutting tool of claim 10 , wherein the cutting element is positioned on a gauge of one of the plurality of radially extending blades.

16. The downhole cutting tool of claim 12 , wherein the radius of curvature is less than 0.120 inches.

17. The downhole cutting tool of claim 12 , wherein the curvature is defined by a portion of an ellipse, a parabola, a hyperbola, a catenary, or a parametric spline.

18. The downhole cutting tool of claim 10 , wherein the downhole cutting tool is a fixed cutter drill bit having the plurality of blades extending from a bit body.

19. The downhole cutting tool of claim 1 , wherein the downhole cutting tool further comprises at least one shear cutter on the first blade.

Assignees

• Schlumberger Technology Corp

Inventors

• Hall David R
• Crockett Ronald B
• Skeem Marcus
• Leany Francis
• Webb Casey

Classifications

• E21B10/55

  with preformed cutting elements · CPC title

• E21C35/183

  with inserts or layers of wear-resisting material {(drill bits with wear-resistant parts E21B10/46)} · CPC title

• E21C35/19

  Means for fixing picks or holders · CPC title

• E21B10/5673 Primary

  having a non planar or non circular cutting face · CPC title

• E21C35/1831 Primary

  Fixing methods or devices · CPC title