Cutting elements comprising partially leached polycrystalline material, tools comprising such cutting elements, and methods of forming wellbores using such cutting elements

Patent metadata

Field	Value
Publication number	US-2016010397-A1
Application number	US-201414329380-A
Country	US
Kind code	A1
Filing date	Jul 11, 2014
Priority date	Jul 11, 2014
Publication date	Jan 14, 2016
Grant date	—

Abstract

An earth-boring tool includes a cutting element having a first volume of polycrystalline material including catalyst material and a second volume free of catalyst material. A boundary between the first volume and the second volume is nonlinear in a cross-sectional plane that includes a centerline of the cutting element and an anticipated point of contact of the cutting element with the surface of the formation to be cut. Each line tangent the boundary in the cross-sectional plane forms an angle with the centerline of the cutting element greater than the contact back rake angle of the cutting element. In some cutting elements, some portions of the boundary may have another selected shape. Some cutting elements have a boundary wherein tangent lines form angles of greater than 20° with the centerline of the cutting element. Methods of forming wellbores are also disclosed.

First claim

What is claimed is:

1 . An earth-boring tool, comprising:
a bit body; and a cutting element secured to the bit body, the cutting element exhibiting a contact back rake angle with respect to a surface of a formation to be cut by the bit body, the cutting element comprising a polycrystalline superabrasive material comprising:
a first volume including catalyst material in interstitial spaces among interbonded grains of the polycrystalline superabrasive material;
a second volume at least substantially free of catalyst material in the interstitial spaces among the interbonded grains of the polycrystalline superabrasive material; and
a continuous boundary between the first volume and the second volume of the polycrystalline superabrasive material, wherein the boundary is nonlinear in a cross-sectional plane that includes a centerline of the cutting element and an anticipated point of contact of the cutting element with the surface of the formation to be cut by the earth-boring tool, and wherein each line tangent the boundary in the cross-sectional plane forms an angle with the centerline of the cutting element greater than the contact back rake angle of the cutting element.

2 . The earth-boring tool of claim 1 , wherein at least a portion of the boundary forms a frustoconical shape.

3 . The earth-boring tool of claim 2 , wherein the frustoconical shape has an axis of revolution substantially coincidental with the centerline of the cutting element.

4 . The earth-boring tool of claim 1 , wherein at least a portion of the boundary forms a paraboloid of revolution.

5 . The earth-boring tool of claim 4 , wherein the paraboloid of revolution has an axis of revolution substantially coincidental with the centerline of the cutting element.

6 . The earth-boring tool of claim 1 , wherein each tangent line in the cross-sectional plane intersects the centerline on a side of the boundary adjacent the second volume.

7 . The earth-boring tool of claim 1 , wherein each tangent line in the cross-sectional plane intersects the centerline on a side of the boundary adjacent the first volume.

8 . The earth-boring tool of claim 1 , wherein each tangent line in the cross-sectional plane forms an angle with the centerline of the cutting element of greater than 30°.

9 . The earth-boring tool of claim 1 , wherein the second volume includes an annular volume adjacent to and extending along a peripheral surface of the cutting element from a working surface of the cutting element to the boundary between the first volume and the second volume.

10 . An earth-boring tool, comprising:
a bit body; and a cutting element secured to the bit body, the cutting element exhibiting a contact back rake angle with respect to a surface of a formation to be cut by the bit body, the cutting element comprising a polycrystalline superabrasive material comprising:
a first volume including catalyst material in interstitial spaces among interbonded grains of the polycrystalline superabrasive material;
a second volume at least substantially free of catalyst material in the interstitial spaces among the interbonded grains of the polycrystalline superabrasive material; and
a boundary between the first volume and the second volume of the polycrystalline superabrasive material, wherein:
the boundary comprises:
a first area including a portion of the boundary within a first radial distance of a centerline of the cutting element in a cross-sectional plane that includes the centerline of the cutting element and an anticipated point of contact of the cutting element with the surface of the formation to be cut by the earth-boring tool; and
a second area including a portion of the boundary between the first radial distance from the centerline of the cutting element and a second radial distance from the centerline of the cutting element in the cross-sectional plane, the second radial distance corresponding to an exterior surface of the cutting element, wherein the first radial distance is at least 50% of the second radial distance;
wherein each line tangent the boundary in the cross-sectional plane in the second area forms an angle with the centerline of the cutting element greater than the contact back rake angle of the cutting element.

11 . The earth-boring tool of claim 10 , wherein the portion of the boundary in the first area forms a frustoconical shape.

12 . The earth-boring tool of claim 10 , wherein the portion of the boundary in the first area focus a paraboloid of revolution.

13 . The earth-boring tool of claim 10 , wherein each line tangent the boundary in the cross-sectional plane intersects the centerline on a side of the boundary adjacent the second volume.

14 . A cutting element for an earth-boring tool, comprising:
a substrate; and a polycrystalline superabrasive material secured to the substrate, the polycrystalline superabrasive material comprising:
a first volume including catalyst material in interstitial spaces among interbonded grains of the polycrystalline superabrasive material;
a second volume at least substantially free of catalyst material in the interstitial spaces among the interbonded grains of the polycrystalline superabrasive material; and
a boundary between the first volume and the second volume of the polycrystalline superabrasive material, wherein the boundary is nonlinear in a cross-sectional plane that includes a centerline of the cutting element and an anticipated point of contact of the cutting element with the surface of the formation to be cut by the cutting element, and wherein each line tangent the boundary in the cross-sectional plane forms an angle with the centerline of greater than 20°.

15 . The cutting element of claim 14 , wherein at least a portion of the boundary forms a frustoconical shape.

16 . The cutting element of claim 14 , wherein at least a portion of the boundary forms a paraboloid of revolution.

17 . The cutting element of claim 14 , wherein each line tangent the boundary in the cross-sectional plane forms an angle with the centerline of the cutting element of greater than 30°.

18 . The cutting element of claim 17 , wherein each line tangent the boundary in the cross-sectional plane forms an angle with the centerline of the cutting element of greater than 45°.

19 . A method of forming a wellbore, comprising:
contacting an earth-boring tool with a surface of a subterranean formation, wherein the earth-boring tool comprises: a bit body; and at least one cutting element secured to the bit body, the at least one cutting element comprising a polycrystalline superabrasive material comprising:
a first volume including catalyst material in interstitial spaces among interbonded grains of the polycrystalline superabrasive material; and
a second volume at least substantially free of catalyst material in interstitial spaces among interbonded grains of the polycrystalline superabrasive material, wherein a surface of the second volume is exposed at least partially around the cutting element;
removing at least a portion of the polycrystalline superabrasive material from the second volume through contact with the surface of the subterranean formation; and removing a portion of the first volume adjacent to and in contact with the second volume without rendering a portion of the second volume radially discontinuous with a remainder of the second volume.

20 . A method of forming a wellbore, comprising:
contacting an earth-boring tool with a surface of a subterranean formation

Assignees

• Baker Hughes Inc

Inventors

• Stockey David A
• Flores Alejandro
• Digiovanni Anthony A

Classifications

• B22F2005/001

  Cutting tools, earth boring or grinding tool other than table ware · CPC title

• C22C26/00

  Alloys containing diamond {or cubic or wurtzitic boron nitride, fullerenes or carbon nanotubes} · CPC title

• E21B10/5676

  having a cutting face with different segments, e.g. mosaic-type inserts · CPC title

• E21B10/567 Primary

  with preformed cutting elements mounted on a distinct support, e.g. polycrystalline inserts · CPC title

• E21B10/5735

  Interface between the substrate and the cutting element · CPC title