Cutting elements having a pre-formed fracture plane for use in cutting tools

Abstract

Cutting elements for cutting tools comprise a pre-formed fracture plane disposed in at least one surface of the cutting elements. The pre-formed fracture plane can comprise a groove cut into one of the surfaces of the cutting element, or the pre-formed fracture plane can be formed by using a laser or other heat concentrating source to weaken a portion of one of the surfaces of the cutting element so that the cutting element will break along the pre-formed fracture plane.

Description

BACKGROUND

1. Field of Invention

The invention is directed to cutting elements or “cutters” for cutting tools used to cut, abrade, or mill objects and, in particular, to cutting elements utilized in tools to cut objects within oil and gas wells, the cutting elements comprising a pre-formed fracture plane to facilitate breakage of the cutting element along a pre-determine location of the cutting element so that the cutting element can either continue to cut away an object in the wellbore, or so that the cutting element can be completely removed so that another cutting element disposed behind the fractured cutting element can begin cutting the object.

2. Description of Art

In the drilling, completion, and workover of oil and gas wells, it is common to perform work downhole in the wellbore with a tool that has some sort of cutting profile interfacing with a downhole structure. Examples would be milling a downhole metal object with a milling tool or cutting through a tubular with a cutting or milling tool. To facilitate these operations, cutting elements are disposed on the downhole cutting tool. In some instances, the cutting elements are stack one on top of another so that when the upper cutting element is worn or broken away, another cutting element can be exposed to the object in the well so that cutting can continue.

SUMMARY OF INVENTION

Broadly, the invention is directed to a cutting element disposed on a downhole cutting tool utilized in cutting away an object disposed within the well, wherein the cutting element comprises at least one pre-formed fracture plane to facilitate breaking away a portion of the cutting element so that the cutting element can continue to cut or abrade the object, or so that a second cutting element disposed behind the broken away cutting element can engage and cut the object. The term “object” encompasses any physical structure that is to be cut, abraded, or milled such as structures disposed within a well, for example, another tool that is stuck within the well, a bridge plug, the well tubing, the well casing, or the like.

In one particular embodiment, the cutting elements are disposed on blades of a downhole cutting tool that are disposed on a face of the tool. The blades are disposed on the face such that rotation of the tool causes rotation of the blades. In other embodiments, the cutting elements are disposed on an end of a mill or other cutting tool.

In one embodiment of the cutting element, the cutting element comprises a pre-formed fracture plane disposed on at least one surface of the cutting element. For example, in a specific embodiment the cutting element comprises a body having a cutting surface and a non-cutting surface wherein the non-cutting surface comprises a fracture plane disposed within the non-cutting surface. In one particular embodiment, the fracture plane comprises a groove cut into the non-cutting surface.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of one specific embodiment of a cutting element disclosed herein.

FIG. 2 is a front view of the cutting element of FIG. 1.

FIG. 3 is a first side view of the cutting element of FIG. 1.

FIG. 4 is a second side view of the cutting element of FIG. 1.

FIG. 5 is an enlarged side view of the view of the cutting element taken along line 5 in FIG. 3.

FIG. 6 is an enlarged side view of the view of the cutting element taken along line 6 in FIG. 3.

FIG. 7 is a bottom view of the cutting element of FIG. 1.

FIG. 8 is a side view of another specific embodiment of a cutting element disclosed herein.

While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to these embodiments. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF INVENTION

Referring now to FIGS. 1-7, cutting element 10 comprises top surface 20, front surface 30, bottom surface 40, first side or lateral surface 50, second side or lateral surface 60, and back surface 70. Top surface 20 comprises cutting profile 22. As shown in the embodiment of FIGS. 1-7, cutting profile 22 comprises a plurality of segments 23 in which a back side 36 of one segment 23 is adjacent to and affixed to a front side 38 of another segment 23. Back sides 36 and front sides 38 are referenced in FIG. 3. As shown in FIG. 6, cutting profile 22 of each segment 23 comprises flat surface 24 having width 25, and angled surface 26 disposed adjacent to flat surface 24 at angle 28. Cutting profile 22 of each segment 23 also includes vertical surface 27 which connects angled surface 26 of one segment 23 to flat surface 24 of an adjacent segment 23. In the embodiment shown in FIGS. 1-7, widths 25 of flat surfaces 24 are in the range from approximately 0.005 inches to approximately 0.02 inches and angle 28 is in the range from approximately 150 degrees to approximately 175 degrees when based upon cutting element 10 having overall dimensions of a width and a length each in the range from approximately 0.3 inches to approximately 1 inch and a height in the range from approximately 0.2 inches to approximately 1 inch.

As shown in FIGS. 1-4 and 7, front surface 30 includes profile 32 connecting front surface 30 with bottom surface 40. Profile 32 can comprises a horizontal groove such as the bevel shown in the Figures, or profile 32 can promise any other shape.

Disposed within bottom surface 40 is at least one groove 44 providing fracture plane 48. In the embodiment of FIGS. 1-7, cutting element 10 comprises a plurality of grooves 44 providing fracture planes 48 between the apexes 45 of grooves 44 and valleys 29 of cutting profile 22. Because grooves 44 are disposed horizontally across a width of cutting element 10, grooves 44 of FIGS. 1-7 are horizontal grooves. As shown in the embodiment of the Figures, grooves 44 comprise angle 46 and depth 47. Angle 46 may be in the range from approximately 40 degrees to approximately 75 degrees and depth 47 may be in the range from approximately 0.01 inches to approximately 0.05 inches when based upon cutting element 10 having overall dimensions of a width and a length each in the range from approximately 0.3 inches to approximately 1 inch and a height in the range from approximately 0.2 inches to approximately 0.75 inches.

Although apexes 45 are shown disposed directly below valleys 29, it is to be understood that the apexes 45 can be moved slightly to the left or right of valleys 29 and still provide the fracture plane 48. In addition, although grooves 44 are shown is V-shaped grooves having apexes 45, it is to be understood that grooves 44 can have any other shape, with or without apexes 45. For example, grooves 44 can comprise a rounded shape, concave or convex curved walls with an apex, and the like.

In the embodiment of FIGS. 1-7, first and second side surfaces 50, 60 comprise grooves 54, 64, respectively which, as shown in this particular embodiment, intersect grooves 44. Grooves 54, 64 facilitate one segment 23 breaking away from an adjacent segment 23 along fracture place 48. Although grooves 54, 64 can have any shape desired or necessary to assist breakage along fracture plane 48, as shown in the embodiment of FIGS. 1-7, grooves 54 and 64 comprise bevels (best shown in FIG. 7) Because grooves 54, 64 shown in FIGS. 1-7 are disposed perpendicular to the grooves 44, grooves 54, 64, these particular grooves 54, 64 are vertical grooves.

Although the dimensions of cutting element 10 can be modified as desired or necessary to facilitate locating cutting element 10 on the cutting tool to maximize the cutting ability of cutting element 10, in one particular embodiment, cutting element 10 comprises a width of 0.5 inches, a length of 0.5 inches, a height of 0.25 inches, a segment width of 0.07 inches, widths 25 measuring 0.1 inches, angle 28 measuring 166 degrees, angle 46 measuring 60 degrees, and groove depth 47 measuring 0.03 inches.

In operation, multiple cutting elements 10 are disposed on a cutting tool, such as on the blade of a cutting mill or directly on the end of the cutting tool. The cutting element is then contacted with an object to be cut, such as an object disposed within a wellbore. The cutting tool is then rotated causing the cutting elements to bite into the object and gradually cut, abrade, or mill away the object. During the cutting operations, one or more of the segments 23 of the cutting elements may hinder the cutting operations such as by causing the cutting tool to jump off of the object, or because the cutting profile has sufficiently worn down that the segment is no longer providing sufficient cutting action. In these situations, grooves 44 and, if present grooves 54 and/or grooves 64, provide a weak point along fracture plane 48 such that the cutting elements will break along a known path, i.e., fracture plane 48. Upon breaking, one of the segments 23 falls away while the remaining segment(s) continue to cut the object in the well until the object is completely cut away or until all of the segments break away from the cutting tool.

In certain embodiments, the cutting elements are stacked on top of one another so that when one cutting element completely breaks away, another cutting element is exposed to the object so that cutting can continue.

In one embodiment, fracture plane 48 of the cutting element is formed by grooves 44 that are disposed in bottom surface 40 by a laser or other similar device that melts and, thus, transforms, a portion of the material of the cutting element such that it is weaker than the remaining material forming the cutting element. Similarly, grooves 54, 64 can be disposed within side walls 50, 60, respectively, using this method. This method of forming the cutting elements allows for the bottom, and if appropriate, side surfaces, to have grooves of weaker material to facilitate breakage along fracture plane 48. This method of forming the cutting elements also allows for the bottom and side surfaces 40, 50, 60 to lack sharp edges which can be broken or cause damage during installation on the cutting tool, yet still provide a weak point to facilitate breakage along fracture plane 48.

Referring now to FIG. 8, in still another embodiment, grooves 44 and, to the extent present, grooves 54 (not shown), 64, of cutting element 110 can be cut and then filled with a material 49 that is weaker than the remaining material forming the cutting element. This method of forming cutting element 110 also allows for the bottom surface 40, and if appropriate, side surfaces 50 (not shown), 60, to have grooves 44, 54 (not shown), 64, respectively filled with weaker material to facilitate breakage along fracture plane 48 and for the bottom and side surfaces 40, 50 (not shown), 60 to lack sharp edges which can be broken or cause damage during installation on the cutting tool, yet still provide a weak point to facilitate breakage along fracture plane 48.

It is to be understood that the invention is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. For example, fracture planes may also be included on the front and back surfaces of the cutting elements. Additionally, side grooves 54, 64 are not required to intersect valleys 29 of cutting profile 22. Instead, grooves 54, 64 can stop prior to reaching valleys 29 of cutting profiles 22. Similarly, grooves 54, 64 are not required to intersect grooves 44. Further, the grooves 54, 64 are not required to be perpendicular with groove 44. Nor do grooves 54, 64 need to be parallel to each other.

Moreover, grooves 44, and if present grooves 54, 64 can have any shape desired or necessary to encourage breakage along fracture plane 48. In addition, the fracture planes do not have to be “flat” as shown in the Figures, but instead can be undulating or curved, and it is to be understood that upon breakage along the fracture plane the surface of the segments are not smooth, but will include burrs and the like.

Further, the cutting elements may be used on any type of cutting tool including but not limited to mill blades, drill bits, and non-blade mills and may be included directly on the face of the cutting end of the tool. In addition, the angles of the fracture planes, cutting profile 22, and profile 32, can be modified as desired or necessary to facilitate placement of the cutting elements on the face or other structure carrying the cutting elements on the cutting end of the cutting tool or to facilitate cutting the object. Likewise, the shapes of the cutting elements can be modified as desired or necessary to facilitate placement of the cutting elements on the face or other structure carrying the cutting elements on the cutting end of the cutting tool. And, the lengths, widths, and heights of the horizontal and vertical side surfaces can also be modified as desired or necessary to facilitate placement of the cutting elements on the face or other structure carrying the cutting elements on the cutting end of the cutting tool or to facilitate cutting the object. In addition, the height does not need to be consistent or constant across either the length or width of the top surface or the length or width of the bottom surface.

Further, the cutting profile can be modified as desired or necessary to facilitate cutting the object. Moreover, the size and shape of the cutting surface portions on the top surface of the cutting elements can be modified as desired or necessary to facilitate placement of the cutting elements on the face or other structure carrying the cutting elements on the cutting end of the cutting tool or to facilitate cutting the object in the wellbore. Therefore, it is to be understood that the invention is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. Accordingly, the invention is therefore to be limited only by the scope of the appended claims.

Claims

1. A cutting element comprising:

a body comprising a cutting surface having a cutting profile and a non-cutting surface, wherein the non-cutting surface comprises a fracture plane disposed within the non-cutting surface.

2. The cutting element of claim 1, wherein the fracture plane is disposed substantially linearly below a valley disposed in the cutting profile.

3. The cutting element of claim 2, wherein the fracture plane comprises a groove.

4. The cutting element of claim 3, wherein the groove comprises a V-shape.

5. The cutting element of claim 1, further comprising a plurality of fracture planes disposed within the non-cutting surface.

6. The cutting element of claim 5, wherein each of the fracture planes is disposed substantially linearly below a respective valley disposed in the cutting profile.

7. The cutting element of claim 6, wherein the cutting surface comprises a top surface and the non-cutting surface comprises a bottom surface disposed opposite the top surface,

wherein the cutting element further comprises at least three side surfaces disposed between the top surface and the bottom surface, and

wherein at least one of the at least three side surfaces comprise a side surface fracture plane, the side surface fracture plane being substantially perpendicular to at least one of the plurality of fracture planes disposed within the bottom surface.

8. The cutting element of claim 1, wherein the cutting surface comprises a top surface and the non-cutting surface comprises a bottom surface disposed opposite the top surface,

wherein the cutting element further comprises a front surface, a back surface disposed opposite the front surface, a first side surface, and a second side surface disposed opposite the first side surface, the front surface, back surface, first side surface, and second side surface being disposed between the top surface and the bottom surface, and

wherein the first side surfaces comprises a side surface fracture plane, the side surface fracture plane being substantially perpendicular to the fracture plane disposed within the bottom surface.

9. A cutting element comprising:

two or more segments, at least one of the two or more segments comprising a top cutting profile and a front side, the front side comprising a horizontal groove disposed opposite the top cutting profile, the horizontal groove providing a fracture plane,

wherein the two or more segments are initially disposed adjacent and affixed to each other along the fracture plane, and

wherein, after sufficient wear of one of the two or more segments, one of the two or more segments breaks apart from the remaining one or more segments along the fracture plane.

10. The cutting element of claim 9, wherein the fracture plane comprises an apex that is disposed substantially linearly below a valley disposed in the top cutting profile.

11. The cutting element of claim 10, wherein the horizontal groove comprises a V-shape.

12. The cutting element of claim 9, the front side of at least one of the two or more segments comprises a vertical groove disposed substantially perpendicular to and connected to the horizontal groove.

13. The cutting element of claim 9, wherein the horizontal groove comprises a material disposed within the horizontal groove, the material being weaker in strength as compared to a cutting element material forming the remainder of the one or more segments.

14. A cutting tool comprising:

a body having a first end for connection with a rotating component; and

a cutting end for rotation in unison with the body, the cutting end comprising a cutting element, the cutting element comprising a cutting surface having a cutting profile and a non-cutting surface, wherein the non-cutting surface comprises a fracture plane disposed within the non-cutting surface,

wherein after sufficient use of the cutting tool, the cutting element breaks along the fracture plane.

15. The cutting element of claim 14, wherein the fracture plane is disposed substantially linearly below a valley disposed in the cutting profile.

16. The cutting element of claim 14, wherein the cutting surface comprises a top surface and the non-cutting surface comprises a bottom surface disposed opposite the top surface,

wherein the cutting element further comprises at least three side surfaces disposed between the top surface and the bottom surface, and

wherein at least one of the at least three side surfaces comprise a side surface fracture plane, the side surface fracture plane being substantially perpendicular to the fracture plane disposed within the bottom surface.

17. A method of cutting an object, the method comprising the steps of:

(a) providing a cutting tool, the cutting tool comprising a cutting element having a cutting surface and a non-cutting surface, wherein the non-cutting surface comprises a fracture plane disposed within the non-cutting surface wherein after sufficient use of the cutting tool, the cutting element breaks along the fracture plane;

(b) contacting the cutting element with an object to be cut;

(c) rotating the cutting element against the object; and

(d) during step (c), breaking the cutting element along the fracture plane to remove a portion of the cutting element from the cutting tool.

18. The method of claim 17, wherein the fracture plane is formed in the non-cutting surface by cutting a groove within the non-cutting surface.

19. The method of claim 18, wherein the fracture plane is formed in the non-cutting surface by heating a portion of the non-cutting surface with a laser.