Polycrystalline diamond bodies having an annular region of diamond grains and a core region of diamond grains and methods of making the same are disclosed. In one embodiment, a polycrystalline diamond body (120) includes an annular region (142) of inter-bonded diamond grains having a first characteristic property and a core region (140) of inter-bonded diamond grains bonded to the annular region and having a second characteristic property that differs from the first characteristic property. The annular region decreases in thickness from a perimeter surface of the polycrystalline diamond body towards a centerline axis.

A cutting element includes a body, a non-planar cutting face formed on a first end of the body, and an edge formed around a perimeter of the cutting face. The cutting face includes a central raised portion, and the edge has an edge angle defined between the cutting face and a side surface of the body. The edge angle varies around the perimeter of the cutting face and includes an acute edge angle defined by a portion of the cutting face extending downwardly from the edge to a depth from the cutting angle. The portion of the edge defining the acute edge angle may be directly adjacent: a side surface of the cutting element; a bevel of the cutting element; or a flat region at the perimeter of the cutting element or bevel.

In this novel PDC cutter, diamond powders of different composition and/or different grain size, are distributed, shaped, and compacted with a novel pressing tool, in multiple stages, spatially arranged into different regions of the PDC diamond body, then HPHT sintered to form one PDC body with spatially varying hardness, toughness and thermal resistance.

A downhole cutting apparatus includes a cutter block. The cutter block includes a formation facing surface with cutting elements coupled thereto. The cutting elements are arranged such that at least one cutting element has a different exposure relative to the formation facing surface than at least one other cutting element. In some embodiments, a row of cutting elements may have a gradually changing exposure. The exposure may change such that cutting elements nearer the gauge of the cutter block have less exposure than cutting elements farther from the gauge of the cutter block. In additional embodiments, an underreamer may include multiple cutter blocks. The cutter blocks may each have a different configuration in a backreaming portion, gauge portion, underreaming portion, any part thereof, or in a combination of the foregoing.

A polycrystalline diamond compact (PDC), which is attached or bonded to a substrate to form a cutter for a drill bit, is comprised of sintered polycrystalline diamond interspersed with a seed material which has a hexagonal close packed (HCP) crystalline structure. A region of the sintered polycrystalline diamond structure, near one or more of its working surfaces, which has been seeded with an HCP seed material prior to sintering, is leached to remove catalyst. Selectively seeding portions or regions of a sintered polycrystalline diamond structure permits differing leach rates to form leached regions with differing distances or depths and geometries.

Polycrystalline diamond bodies having an annular region of diamond grains and a core region of diamond grains and methods of making the same are disclosed. In one embodiment, a polycrystalline diamond body includes an annular region of inter-bonded diamond grains having a first characteristic property and a core region of inter-bonded diamond grains bonded to the annular region and having a second characteristic property that differs from the first characteristic property. The annular region decreases in thickness from a perimeter surface of the polycrystalline diamond body towards a centerline axis.

A cutting bit includes a body, a plurality of blades, and at least one ultrahard insert cast directly into at least one of the plurality of blades. The ultrahard insert is positioned with a rear face directly contacting the blade.

A cutting assembly for use in a drill bit has an ovoid insert including an ultrahard material. The ovoid insert is cast in a matrix such that the matrix surrounds at least part of the ovoid insert, limiting movement of the ovoid insert. Material is removed from the top surface and sidewall of the cutting assembly to produce a cutting edge.

A cutting device for use in a drill bit has a body including an ultrahard material. The body has a top surface, a front surface, and at least one lateral surface adjacent the top surface. The lateral surface is oriented at a surface angle relative to the top surface between 30 and 150 degrees. One or more locking features are located on the lateral surface.

Embodiments of the invention relate to polycrystalline diamond compacts (PDCs) comprising a polycrystalline diamond (PCD) table including at least a portion having aluminum carbide disposed interstitially between bonded-together diamond grains thereof, and methods of fabricating such PDCs. In an embodiment, a PDC includes a substrate, and a PCD table bonded to the substrate. The PCD table includes a plurality of bonded-together diamond grains defining a plurality of interstitial regions. The PCD table further includes aluminum carbide disposed in at least a portion of the plurality of interstitial regions.