Abstract:
The present invention relates to a drill bit having a bit body and a plurality of cutters, which are configured to disintegrate earthen formation as the bit body is rotated by a connected drill string. At least some of the cutters have a first and second body, first and second cutting faces and first and second cutting edges. The body is comprised of hard metal. The cutting elements are comprised of superhard material. The orientation of the first cutter body is reversible as to the other components to permit variation in the proximity of the first and second cutting elements.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present invention relates to a drill bit for drilling bore holes in earthen formations. More particularly, the present invention relates to a drill bit having a plurality of cutters that includes multiple cutting areas. 
       BACKGROUND OF THE INVENTION 
       [0002]    In the exploration of oil, gas, and geothermal energy, drilling operations are used to create boreholes, or wells, in the earth. Drill bits are in the center of such operations, disintegrating earthen formation. A drill bit substantially has a bit body connected by a drill string in one end and a plurality of cutters/cutting elements on the other end of the bit body. Conventionally, these cutters have one cutting area that is made of superhard material, such as polycrystalline diamond. While these cutters have been effective in disintegrating earthen formation, there always has been a need for more effective cutters that can expedite the drilling operations. 
       SUMMARY OF THE INVENTION 
       [0003]    It is a general object of the present invention to provide improved earth boring cutters or cutting elements for a drill bit and improved drill bits. 
         [0004]    An earth-boring bit is disclosed. The drill bit has a bit body configured for connection to a drill string. A plurality of cutters is secured to the bit body. The cutters are configured to disintegrate earthen formation as the bit body is rotated by the drill string. 
         [0005]    At least one of the cutters comprises a substantially cylindrical first body made of hard metal. A substantially cylindrical first cutting element is attached to an end of the first body. The cutting element is made of a superhard material. A trailing end defines the opposite end of the first body. A first cutting face is located on the first cutting element. A first cutting edge defines a beveled perimeter of the first cutting face. A cylindrical slot is formed in the first body. A substantially cylindrical second body made of hard metal is located in the slot. A substantially cylindrical second cutting element is attached to an end of the second body. The second cutting element is made of a superhard material. A second cutting face is located on the second cutting element. A second cutting edge defines a beveled perimeter of the second cutting face. 
         [0006]    In accordance with another exemplary embodiment, the hard metal comprises tungsten carbide. In accordance with another exemplary embodiment, the superhard material comprises polycrystalline diamond. In accordance with another exemplary embodiment, the cutting faces are flat. 
         [0007]    One of the principal advantages of the exemplary embodiments is that it provides an additional cutting edge and face to a conventional cutter, which only has one cutting edge and face. Another advantage of the exemplary embodiments is that its additional cutting edge and face can have different orientation from the first cutting edge and face, allowing the bit to disintegrate an area of earthen formation where the first cutting edge and face cannot reach. Naturally, it will improve the effectiveness of a drilling operation, saving significant amounts of time and cost for the operation. 
         [0008]    As referred to hereinabove and throughout, the “present invention” refers to one or more exemplary embodiments of the present invention, which may or may not be claimed, and such references are not intended to limit the language of the claims, or to be used to construe the claims in a limiting manner. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The objects and features of the invention will become more readily understood from the following detailed description and appended claims when read in conjunction with the accompanying drawings in which like numerals represent like elements. 
           [0010]    The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention. 
           [0011]      FIG. 1  is a side view of prior art, a drill bit comprising a plurality of single tiered cutters. 
           [0012]      FIG. 2  is a side view of a drill bit in accordance with one of the exemplary embodiments. 
           [0013]      FIG. 3  is an isometric view of a cutter in accordance with one of the exemplary embodiments and shown in  FIG. 2 . 
           [0014]      FIG. 4  is an isometric view of a cutter in accordance with another exemplary embodiment. 
           [0015]      FIG. 5  is an exploded view of the cutter shown in  FIG. 4 . 
           [0016]      FIG. 6  is an isometric view of a cutter in accordance with another exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. As used herein, “substantially” is to be construed as a term of approximation. 
         [0018]    As referenced herein throughout, the term “hard metal” refers to metal that is hard enough to withstand pressures and force necessitated in disintegrating earthen formation during drilling operation. Examples of such hard metal include cemented tungsten carbide and the like. The term “superhard material” refers to material that possesses hardness similar to diamonds and greater than that of hard metal. Examples of such superhard material include polycrystalline diamond, cubic boron nitride, thin-film diamond, and the like. 
         [0019]    Referring to  FIG. 1 , a side view of a conventional earth-boring drill bit  1  is shown. Conventional earth-boring drill bit  1  comprises a bit body  10  connected to a drill string  30  on one end and a plurality of cutters  20  secured on the other end. As shown, each of the cutters  20  in the conventional earth-boring drill bit  1  has one cutting edge and face. 
         [0020]    Referring to  FIG. 2 , a side view of an exemplary embodiment of an earth-boring drill bit  1 ′ is shown. Drill bit  1 ′ comprises a bit body  10 ′ connected to a drill string  30 ′ on one end, and a plurality of cutters  100  secured on the opposite end. Bit body  10 ′ is substantially cylindrical in shape. As the drill string  30 ′ rotates, so does the drill bit  1 ′, disintegrating earthen formation with its cutters  100 . Drill bit  1 ′ may comprise other exemplary cutters  100 ,  200 ,  300 , or a combination thereof, as shown in  FIGS. 3-6 . 
         [0021]      FIG. 3  is an isometric view of one of the exemplary cutters  100  shown in  FIG. 2 . Cutter  100  has a first body  110  that includes a first cutting element  112  and a first trailing end  114 . First body  110  is substantially cylindrical in shape and may be comprised of hard metals, such as tungsten carbide. First cutting element  112  is substantially cylindrical in shape and includes a first cutting face  118  and a first cutting edge  116 . First cutting face  118  is located on top of first cutting element  112  and may be substantially flat. First cutting edge  116  defines the perimeter of first cutting face  118  and may be comprised of superhard materials, such as polycrystalline diamond. 
         [0022]    In  FIG. 3 , between first cutting element  112  and first trailing end  114  of first body  110 , there is a second body  120 . Second body  120  is substantially cylindrical in shape and has a second cutting element  122  and a second trailing end  124 . Second cutting element  122  is substantially cylindrical in shape and has a second cutting face  128  and a second cutting edge  126 . Second cutting face  128  is located on top of second cutting element  122  and is substantially flat. Second cutting edge  126  defines the perimeter of second cutting face  128  and may be comprised of superhard materials, such as polycrystalline diamond. Second body  120  may be comprised of hard metals, such as tungsten carbide. Planes of cutting faces  118 ,  128  may be parallel. 
         [0023]    Second body  120  may be located anywhere between first cutting element  112  and first trailing end  114 . The axis (not numbered) of second body  120  may be parallel to the axis (not numbered) of first body  110 . A slot  140  (not shown) in first body  110  where second body  120  may be inserted may be formed using a cylindrical diamond grinder. Second body  120  may be bonded to slot  140  (not shown) by brazing or chemical adhesive. 
         [0024]    In an alternative embodiment, first  110  and second  120  cutter bodies may be integrally formed during the sintering process. The size or diameter of slot  140  may vary by the size or diameter of the second body  120 . In the preferred embodiment, the diameter of first body  110  is greater than the diameter of second body  120 . In the more preferred embodiment, the diameter of second body  120  is between 80% and 50% of the diameter of first body  110 . 
         [0025]    In an alternative embodiment, not shown, the orientation of first body  110  can be reversed in relationship to first cutting element  112 , such that trailing end  114  is adjacent first cutting element  112 . In this embodiment, first body  110  provides additional backing support to the forces acting on second cutting element  122  during drilling. This also permits a variable spacing as between first cutting element  112  and second cutting element  122 , by moving second cutting element  122  into closer proximity to first cutting element  112 . 
         [0026]    Referring to  FIGS. 4 and 5 , another embodiment of exemplary cutters  200  is illustrated. A substantially cylindrical first body  210  is made of a hard metal, such as tungsten carbide. A substantially cylindrical first cutting element  212  is attached to one end of first body  210  by brazing or other method. First cutting element  212  is made of a superhard material, such as polycrystalline diamond. A trailing end (not shown) defines the opposite end of first body  210 . 
         [0027]    In a preferred embodiment, first cutting element  212  is substantially cylindrical in shape and includes a first cutting face  218  and a first cutting edge  216 . First cutting face  218  is located on top of first cutting element  212  and may be substantially flat. First cutting edge  216  defines the perimeter of first cutting face  218 . 
         [0028]    A substantially cylindrical second body  230  is made of hard metal, such as tungsten carbide, and is attached in axial alignment to trailing end (not shown) of first body  210 . As seen in  FIG. 5 , a cylindrical slot  240  is formed in second body  230 . A substantially cylindrical third body  220  is also made of hard metal, such as tungsten carbide. Third body  220  is located in slot  240 . A substantially cylindrical second cutting element  222  is attached to one end of third body  220 . Second cutting element  220  is made of a superhard material, such as polycrystalline diamond. 
         [0029]    In a preferred embodiment, second cutting element  222  is substantially cylindrical in shape and includes a second cutting face  228  and a second cutting edge  226 . Second cutting face  228  is located on top of second cutting element  222  and may be substantially flat. Second cutting edge  226  defines the perimeter of second cutting face  228 . In a preferred embodiment, the planes of first  218  and second  228  cutting faces are substantially parallel. 
         [0030]    Third body  220  may have the same length as second body  230  but may also be shorter. The axes (not numbered) of first body  210 , second body  230  and third body  220  may be parallel to the axis (not numbered) of first body  210 . Slot  240  in second body  230 , where third body  220  may be inserted, may be formed using a cylindrical diamond grinder. Third body  220  may be bonded to slot  240  by brazing. When inserted, second body  230  provides a carbide backing support to third body  220 . The size or diameter of slot  240  may vary by the size or diameter of third body  220 . Slot  240  may be partially formed in first body  210 . Alternatively, cutter bodies  230  and  220  may be integrally formed during the sintering process. 
         [0031]    In an alternative embodiment (not shown), the orientation of second body  230  can be reversed in relationship to first cutting element  212 . The location of first body  210  is then relocated to behind second body  230 . In this embodiment, first body  210  provides additional backing support to the forces acting on second cutting element  222  during drilling. This also permits a variable spacing as between first cutting element  212  and second cutting element  222  by moving second cutting element  222  into closer proximity to first cutting element  212 . 
         [0032]      FIG. 6  is an isometric view of one of the exemplary cutters  300 . Exemplary cutter  300  has a body  310  that includes a cutting element  312  and a trailing end  314 . Body  310  is generally cylindrical in shape. Between cutting element  312  and trailing end  314 , a spherical body  330  extends from body  310 . Spherical body  330  and body  310  may be comprised of hard metals, such as tungsten carbide. Spherical body  330  may be bonded by brazing to a slot (not numbered) formed in body  310 . The slot may be formed using a diamond grinder. Cutting element  312  is substantially cylindrical in shape and has a cutting face  318  and a cutting edge  316 . Cutting face  318  is located on top of cutting element  312  and is substantially flat. Cutting edge  316  defines the perimeter of cutting face  318 . Cutting element  312  may be comprised of superhard materials, such as polycrystalline diamond. 
         [0033]    It will be readily apparent to those skilled in the art that the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. 
         [0034]    Having thus described the exemplary embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.