Downhole Drill Bit Incorporating Cutting Elements of Different Geometries
A downhole cutting tool may include a tool body, a plurality of blades extending from the tool body, and a plurality of cutting elements coupled to the blades. The plurality of cutting elements may include one or more cutting elements having a working end of a first geometry (e.g., a pointed geometry) and one or more cutting elements having a working end of a second geometry (e.g., a planar geometry).
This application is a continuation of U.S. Pat. No. 9,708,856, filed on May 20, 2015, which is a continuation of U.S. Pat. No. 9,051,795, filed on Nov. 25, 2013, which is a continuation of U.S. Pat. No. 8,590,644, filed on Sep. 26, 2007, which is a continuation-in-part of U.S. Pat. No. 8,622,155, filed on Jul. 27, 2007, which is a continuation-in-part of U.S. Pat. No. 8,122,980, filed on Jun. 22, 2007. U.S. Pat. No. 8,590,644 is also a continuation-in-part of U.S. Pat. No. 7,669,938, filed on Jul. 6, 2007, which is a continuation-in-part of U.S. Pat. No. 7,997,661, filed on Jul. 3, 2007, which is a continuation-in-part of U.S. patent application Ser. No. 11/766,903, filed on Jun. 22, 2007, which is continuation of U.S. patent application Ser. No. 11/766,865, filed on Jun. 22, 2007, which is a continuation-in-part of U.S. Pat. No. 7,475,948, filed on Apr. 30, 2007, which is a continuation of U.S. Pat. No. 7,469,971, which is a continuation-in-part of U.S. Pat. No. 7,338,135, filed on Aug. 11, 2006, which is a continuation-in-part of U.S. Pat. No. 7,384,105, filed on Aug. 11, 2006, which is a continuation-in-part of U.S. Pat. No. 7,320,505, filed on Aug. 11, 2006, which is a continuation-in-part of U.S. Pat. No. 7,445,294, filed on Aug. 11, 2006, which is a continuation-in-part of U.S. Pat. No. 7,413,256, filed on Aug. 11, 2006. U.S. Pat. No. 8,590,644 is also a continuation-in-part of U.S. Pat. No. 7,396,086, filed on Apr. 3, 2007, which is a continuation-in-part of U.S. Pat. No. 7,568,770, filed on Mar. 16, 2007.
BACKGROUNDThis invention relates to drill bits, specifically drill bit assemblies for use in oil, gas and geothermal drilling. More particularly, the invention relates to cutting elements in rotary drag bits comprised of a carbide substrate with a non-planar interface and an abrasion resistant layer of superhard material affixed thereto using a high-pressure high-temperature (HPHT) press apparatus. Such cutting elements typically comprise a superhard material layer or layers formed under high temperature and pressure conditions, usually in a press apparatus designed to create such conditions, cemented to a carbide substrate containing a metal binder or catalyst such as cobalt. A cutting element or insert is normally fabricated by placing a cemented carbide substrate into a container or cartridge with a layer of diamond crystals or grains loaded into the cartridge adjacent one face of the substrate. A number of such cartridges are typically loaded into a reaction cell and placed in the HPHT apparatus. The substrates and adjacent diamond crystal layers are then compressed under HPHT conditions which promotes a sintering of the diamond grains to form the polycrystalline diamond structure. As a result, the diamond grains become mutually bonded to form a diamond layer over the substrate interface. The diamond layer is also bonded to the substrate interface.
Such cutting elements are often subjected to intense forces, torques, vibration, high temperatures and temperature differentials during operation. As a result, stresses within the structure may begin to form. Drag bits for example may exhibit stresses aggravated by drilling anomalies during well boring operations such as bit whirl or bounce often resulting in spalling, delamination or fracture of the superhard abrasive layer or the substrate thereby reducing or eliminating the cutting elements efficacy and decreasing overall drill bit wear life. The superhard material layer of a cutting element sometimes delaminates from the carbide substrate after the sintering process as well as during percussive and abrasive use. Damage typically found in drag bits may be a result of shear failures, although non-shear modes of failure are not uncommon. The interface between the superhard material layer and substrate is particularly susceptible to non-shear failure modes due to inherent residual stresses.
U.S. Pat. No. 6,332,503 to Pessier et al., which is herein incorporated by reference for all that it contains, discloses an array of chisel-shaped cutting elements mounted to the face of a fixed cutter bit, each cutting element has a crest and an axis which is inclined relative to the borehole bottom. The chisel-shaped cutting elements may be arranged on a selected portion of the bit, such as the center of the bit, or across the entire cutting surface. In addition, the crest on the cutting elements may be oriented generally parallel or perpendicular to the borehole bottom.
U.S. Pat. No. 6,059,054 to Portwood et al., which is herein incorporated by reference fir all that it contains, discloses a cutter element that balances maximum gage-keeping capabilities with minimal tensile stress induced damage to the cutter elements is disclosed. The cutter elements of the present invention have a nonsymmetrical shape and may include a more aggressive cutting profile than conventional cutter elements. In one embodiment, a cutter element is configured such that the inside angle at which its leading face intersects the wear face is less than the inside angle at which its trailing face intersects the wear face. This can also be accomplished by providing the cutter element with a relieved wear face. In another embodiment of the invention, the surfaces of the present cutter element are curvilinear and the transitions between the leading and trailing faces and the gage face are rounded, or contoured. In this embodiment, the leading transition is made sharper than the trailing transition by configuring it such that the leading transition has a smaller radius of curvature than the radius of curvature of the trailing transition. In another embodiment, the cutter element has a chamfered trailing edge such that the leading transition of the cutter element is sharper than its trailing transition. In another embodiment, the cutter element has a chamfered or contoured trailing edge in combination with a canted wear face. In still another embodiment, the cutter element includes a positive rake angle on its leading edge.
SUMMARYIn one aspect, a drill bit has a body intermediate a shank and a working face. The working face has a plurality of blades converging towards a center of the working face and diverging towards a gauge of the working face. A first blade has at least one pointed cutting element with a carbide substrate bonded to a diamond working end with a pointed geometry at a non-planar interface and a second blade has at least one shear cutting element with a carbide substrate bonded to a diamond working end with a flat geometry.
The carbide substrate bonded to the pointed geometry diamond working may have a tapered geometry. A plurality of first blades having the at least one pointed cutting element may alternate with a plurality of second blades having the at least one shear cutting element. A plurality of cutting elements may be arrayed along any portion of their respective blades including a cone portion, nose portion, flank portion, gauge portion, or combinations thereof. When the first and second blades are superimposed on each other, an axis of the at least one pointed cutting element may be offset from an axis of the at least one shear cutting element. An apex of the pointed cutting element may have a 0.050 to 0.200 inch radius. The diamond working end of the pointed cutting element may have a 0.090 to 0.500 inch thickness from the apex to the non-planar interface. A central axis of the pointed cutting element may be tangent to its intended cutting path during a downhole drilling operation. In other embodiments, the central axis of the pointed cutting element may be positioned at an angle relative to its intended cutting path during a downhole drilling operation. The angle of the at least one pointed cutting element on the first blade may be offset from an angle of the at least one shear cutting element on the second blade. A pointed cutting element on the first blade may be oriented at a different angle than an adjacent pointed cutting element on the same blade. The pointed cutting element and the shear cutting element may have different rake angles. The pointed cutting element may generally comprise a smaller rake angle than the shear cutting element. A first pointed cutting element may be located further from the center of the working face than a first shear cutting element. The carbide substrate of the pointed cutting element may be disposed within the first blade. The non-planar interface of the shear cutting element may comprise at least two circumferentially adjacent faces, outwardly angled from a central axis of the substrate.
In the embodiment of
Also in this embodiment, a plurality of cutting elements 207, 209, may be arrayed along any portion of their respective blades 206, 208, including a cone portion 210, nose portion 211, flank portion 212, gauge portion 205, or combinations thereof.
Also shown in
Referring now to another embodiment of the drill bit 104B illustrated in
Referring now to another embodiment of the drill bit 104C illustrated in
In the embodiment of the drill bit 104D shown in
Referring now to
In the embodiment of the drill bit 104G illustrated in
Referencing yet another representative embodiment of the drill bill 104H,
In the embodiment 1041 of
In the embodiment of a pointed cutting element 1822 illustrated in
Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention.
Claims
1. A downhole cutting tool, comprising:
- a tool body;
- a plurality of blades extending from the tool body; and
- a plurality of cutting elements coupled to the plurality of blades, the plurality of cutting elements including: a first cutting element on a first blade of the plurality of blades, the first cutting element having a working end of a first geometry; and a second cutting element on a second blade of the plurality of blades, the second cutting element having a working end of a second geometry that is different than the first geometry, and a central axis of the second cutting element being radially or angularly offset from a central axis of the first cutting element when the plurality of blades are superimposed on each other.
2. The downhole cutting tool of claim 1, the first cutting element being a pointed cutting element, the working end of the pointed cutting element forming an apex.
3. The downhole cutting tool of claim 2, a thickness of the working end being measured from an outer surface of the pointed cutting element to an interface with a substrate, and the thickness being greatest at the apex.
4. The downhole cutting tool of claim 2, the pointed cutting element including a concave side wall between the apex and an interface with a substrate.
5. The downhole cutting tool of claim 2, the pointed cutting element including a convex side wall between the apex and an interface with a substrate.
6. The downhole cutting tool of claim 2, the pointed cutting element including a flat side wall forming an included angle between 35° and 45° relative to the central axis of the pointed cutting element.
7. The downhole cutting tool of claim 2, the apex having a radius of curvature between 0.050 inch and 0.200 inch.
8. The downhole cutting tool of claim 1, the second cutting element being a shear cutting element, the working end of the shear cutting element forming a planar cutting surface.
9. The downhole cutting tool of claim 1, the first blade being adjacent to, and rotationally leading, the second blade.
10. The downhole cutting tool of claim 1, the second blade being adjacent to, and rotationally leading, the first blade.
11. The downhole cutting tool of claim 1, the plurality of blades including a plurality of first blades alternating with a plurality of second blades.
12. The downhole cutting tool of claim 1, the first cutting element and the second cutting element having different rake angles.
13. The downhole cutting tool of claim 1, the plurality of cutting elements including a third cutting element having a working end of the first geometry, the central axis of the first cutting element being at a different angle relative to an intended cutting path formed by a working face of the downhole cutting tool than a central axis of the third cutting element.
14. A fixed cutter drill bit, comprising:
- a tool body;
- a plurality of blades extending from the tool body; and
- a plurality of cutting elements coupled to the plurality of blades, the plurality of cutting elements including: a plurality of pointed cutting elements on a first blade of the plurality of blades, the plurality of pointed cutting elements including a working end with a substantially pointed geometry that is opposite a first base; and a plurality of shear cutters on a second blade of the plurality of blades, the plurality of shear cutting elements including a working end with a planar cutting surface opposite a second base, and an innermost shear cutting element of the plurality of shear cutting elements being nearer a center of a working face of the tool body than an innermost pointed cutting element of the plurality of pointed cutting elements.
15. The fixed cutter drill bit of claim 14, a central axis of at least one of the plurality of pointed cutting elements being angled relative to a central axis of at least one of the plurality of shear cutting elements.
16. The fixed cutter drill bit of claim 14, the substantially pointed geometry including a side wall that tangentially joins an apex having a radius of curvature.
17. The fixed cutter drill bit of claim 14, at least one of the plurality of pointed cutting elements being at a different rake angle relative to at least one of the plurality of shear cutting elements.
18. The fixed cutter drill bit of claim 14, wherein when the plurality of blades are superimposed on each other, a central axis of at least one of the plurality of pointed cutting elements is radially between central axes of at least two of the plurality of shear cutting elements, and a central axis of at least one of the plurality of shear cutting elements is radially between central axes of at least two of the plurality of pointed cutting elements.
19. A downhole cutting tool, comprising:
- a tool body;
- a plurality of blades extending from the tool body; and
- a plurality of cutting elements coupled to the plurality of blades, the plurality of cutting elements including: at least one first cutting element having a working end of a first geometry; and at least one second cutting element having a working end of a second geometry that is different than the first geometry.
20. The downhole cutting tool of claim 19, the first geometry being a pointed geometry with an apex, and the second geometry being a shear geometry with a planar cutting face.
Type: Application
Filed: Jul 17, 2017
Publication Date: Sep 13, 2018
Patent Grant number: 10378288
Inventors: David R. Hall (Provo, UT), John D. Bailey (Provo, UT), Ronald B. Crockett (Provo, UT)
Application Number: 15/651,308