Abstract: A method is disclosed for leaching a polycrystalline diamond (PCD) cutter element. In an embodiment, the method includes suspending the PCD cutter element above a liquid acid bath. In addition, the method includes elevating the temperature of the liquid acid bath above ambient conditions to transition at least some of the liquid acid bath to acid vapors. Further, the method includes elevating the pressure of the acid vapors above ambient conditions. Still further, the method includes exposing the PCD cutter element to the acid vapors.

Abstract: A system for leaching a polycrystalline diamond (PCD) cutter element having a PCD table and a substrate, the system including a housing having an open first end and a closed second end and a lid removably and sealingly attached the first end of the housing. The housing and the lid define an inner chamber extending between the first end and the second end, and the inner chamber is configured to receive and hold a volume of liquid acid therein. In addition, the system includes a cutter element holder disposed within the inner chamber, wherein the PCD cutter element is suspended above the volume of liquid acid in the inner chamber with the holder.

Abstract: A method and apparatus for distributing granular constituents within polycrystalline diamond composites is disclosed in one embodiment of the invention as including providing a mixture of diamond particles of various different sizes. This mixture is then agitated to substantially segregate the diamond particles within the mixture according to particle size. The segregated mixture may then be sintered to fuse the diamond particles together and thereby immobilize the diamond particles within the mixture. In selected embodiments, the mixture may be agitated while adjacent to a substrate material. The mixture may be fused to the substrate when the diamond particles are sintered.

Abstract: Disclosed is a polycrystalline diamond or diamond-like element with greatly improved wear resistance without loss of impact strength. These elements are formed with a binder-catalyzing material in a high-temperature, high-pressure (HTHP) process. The PCD element has a body with a plurality of bonded diamond or diamond-like crystals forming a continuous diamond matrix that has a diamond volume density greater than 85%. Interstices among the diamond crystals form a continuous interstitial matrix containing a catalyzing material. The diamond matrix table is formed and integrally bonded with a metallic substrate containing the catalyzing material during the HTHP process. The diamond matrix body has a working surface, where a first portion of the interstitial matrix in the body adjacent to the working surface is substantially free of the catalyzing material, and a second portion of the interstitial matrix in the body adjacent to the working surface contains the catalyzing material.

Abstract: A method is disclosed comprising the steps of locating, on a surface of a downhole component, a plurality of thermally stable polycrystalline diamond (TSP) bearing elements, and then applying to the surface a settable facing material which bonds to the surface between the bearing elements and embraces the elements to hold them in place. A method in which bearing elements each comprising a body of TSP at least partly surrounded by a layer of less hard material are secured to the surface by welding or brazing part of the surface of each bearing element which comprises said less hard material to said component is also described.

Abstract: A rotary drill bit includes cutters arranged in a series of concentric rings, the cutters of one of the rings having a different wear resistance to the cutters of another of the rings with the result that the stability of the drill bit improves with wear. Although the wear resistance is different, the cutters have substantially the same impact toughness.

Abstract: A preform cutting element, for a rotary drill bit, and a rotary drill bit with prefrom cutting elements including a facing table of superhard material having a front face, a rear surface is bonded to the front surface of a substrate which is less hard than the superhard material and has a rim or edge section of the superhard material at least partially covered by a metallic material different from the substrate material. The metallic material is bonded to the edge section of the superhard material through a high pressure bonding step. The superhard material covered by the compliant metallic material is protected from impact forces occurring in drill bit operations such as tripping.

Abstract: A method for use in designing rotary drill bits comprises determining locations in which cutters are to be provided, determining likely wear rates for cutters positioned at those locations, and using the likely wear rates to chose between relatively high and relatively low wear rate cutters for each location. The cutters all have substantially the same impact toughness.

Abstract: Disclosed is a polycrystalline diamond or diamond-like element with greatly improved wear resistance without loss of impact strength. These elements are formed with a binder-catalyzing material in a high-temperature, high-pressure (HTHP) process. The PCD element has a body with a plurality of bonded diamond or diamond-like crystals forming a continuous diamond matrix that has a diamond volume density greater than 85%. Interstices among the diamond crystals form a continuous interstitial matrix containing a catalyzing material. The diamond matrix table is formed and integrally bonded with a metallic substrate containing the catalyzing material during the HTHP process. The diamond matrix body has a working surface, where a first portion of the interstitial matrix in the body adjacent to the working surface is substantially free of the catalyzing material, and a second portion of the interstitial matrix in the body adjacent to the working surface contains the catalyzing material.

Abstract: A rotary drill bit includes cutters arranged in a series of concentric rings, the cutters of one of the rings having a different wear resistance to the cutters of another of the rings with the result that the stability of the drill bit improves with wear. Although the wear resistance is different, the cutters have substantially the same impact toughness.

Abstract: A method for use in designing rotary drill bits comprises determining locations in which cutters are to be provided, determining likely wear rates for cutters positioned at those locations, and using the likely wear rates to chose between relatively high and relatively low wear rate cutters for each location. The cutters all have substantially the same impact toughness.

Abstract: A method is disclosed comprising the steps of locating, on a surface of a downhole component, a plurality of thermally stable polycrystalline diamond (TSP) bearing elements, and then applying to the surface a settable facing material which bonds to the surface between the bearing elements and embraces the elements to hold them in place. A method in which bearing elements each comprising a body of TSP at least partly surrounded by a layer of less hard material are secured to the surface by welding or brazing part of the surface of each bearing element which comprises said less hard material to said component is also described.

Abstract: A method of applying a wear-resistant material to a surface of a downhole component for use in subsurface drilling comprises forming a plurality of bearing elements, applying a layer of an electrically conductive, less hard material to each bearing element, and then bonding each bearing element to the surface of the component by welding or brazing to the surface of the component a part of the surface of the bearing element which comprises said less hard material, wherein the layer is of thickness greater than 0.05mm.

Abstract: A method is disclosed comprising the steps of locating, on a surface of a downhole component, a plurality of thermally stable polycrystalline diamond (TSP) bearing elements, and then applying to the surface a settable facing material which bonds to the surface between the bearing elements and embraces the elements to hold them in place. A method in which bearing elements each comprising a body of TSP at least partly surrounded by a layer of less hard material are secured to the surface by welding or brazing part of the surface of each bearing element which comprises said less hard material to said component is also described.

Abstract: A preform cutting element, for a rotary drag-type drill bit, includes a facing table of polycrystalline diamond having a front face, a peripheral surface, and a rear surface bonded to the front surface of a tungsten carbide substrate. The facing table has at least one peripheral locking portion projecting rearwardly from the rear surface of the facing table into the substrate, the inner surface of the locking portion and the adjacent part of the substrate having interengaging formations whereby part of the substrate overlies at least one part of the locking portion. With this arrangement, forces acting on the facing table tending to lift it from the front surface of the substrate are resisted by the portion of the substrate which overlies the part of the locking portion.

Abstract: A preform cutting element, for a rotary drag-type drill bit, includes a facing table of superhard material having a front face, a peripheral surface, and a rear surface bonded to the front surface of a substrate which is less hard than the superhard material. The facing table extends across only a part of the front surface of the substrate, and part of the substrate engages the peripheral surface of the facing table. When such a cutting element is mounted on a bit body with the part of the facing table periphery which is engaged by the substrate being located opposite the cutting edge of the element, the part of the substrate which engages the periphery of the facing table acts as a mechanical support to the facing table so as to resist impact and other loads to which the facing table may be subject in use.

Abstract: A preform element, such as a preform cutting element for a rotary drag-type drill bit, includes a facing table of polycrystalline diamond having a front face, a peripheral surface, and a rear surface bonded to the front surface of a tungsten carbide substrate. The front surface of the substrate is formed with a plurality of recesses into which extend corresponding projections formed on the rear surface of the facing table. The recesses include at least one rebate which extends around only a part of the periphery of the substrate and into which extends a projection on the facing table which provides a part of the peripheral surface of the facing table.

Abstract: A method of manufacturing preform elements comprises the initial step of forming a preliminary component including a facing table of superhard material having a front face, a peripheral surface, and a rear surface bonded to a less hard substrate. The rear surface of the facing table and the front surface of the substrate are formed with inter-engaging projections and recesses to provide a non-planar interface between the substrate and facing table. There are then cut from the preliminary component a plurality of separate preform elements each having a facing table and substrate with a non-planar interface between them. The configuration of the non-planar interface of the preliminary component may vary with distance from its center, so that the non-planar interface of each preform element also varies in configuration across the width of the element.

Abstract: A preform element, for example for use as a cutting element on a rotary drag-type drill bit, includes a facing table of superhard material having a front face and a rear face bonded to the front face of a substrate which is less hard than the superhard material. The rear face of the facing table comprises a surface formed with a plurality of spaced protuberances and a plurality of spaced sockets, and the front face of the substrate comprises a surface which is bonded to the surface of the facing table and is formed with a plurality of spaced protuberances which are bonded within said sockets in the facing table, and a plurality of spaced sockets within which are bonded said protuberances on the facing table.

Abstract: In a rotary drag-type drill bit, or other downhole component used in subsurface drilling, bearing pads which engage the surface of the earthen formation of the borehole carry wear-resistant bearing inserts received in sockets in the bearing pad. Each bearing insert includes a preform element of the kind normally used as cutting elements in drag-type drill bits, and having a front facing table of polycrystalline diamond bonded to a less hard substrate. The preform element is orientated so that its front diamond surface is tangential to the surface of the bearing pad, or at a slight angle thereto, so as to provide a highly wear-resistant, but non-aggressive bearing insert. The preform element may be bonded to or partly embedded in a carrier which is received within the socket. The element or carrier may be formed with spaced longitudinal ribs to allow it to be force-fitted into the socket, or the element or carrier may be secured within a hollow sleeve which is formed with such ribs.