The present disclosure provides a sintering assembly and a polycrystalline diamond compact (PDC) including a acid-labile leach-enhancing material, a PDC including cavities formed by removal of an acid-labile leach-enhancing material, and a method of forming a leached PDC using an acid-labile leach-enhancing material. The present disclosure further includes drill bits using PDCs formed suing an acid-labile leach-enhancing material.

The present disclosure provides a sintering assembly and a polycrystalline diamond compact (PDC) including a acid-labile leach-enhancing material, a PDC including cavities formed by removal of an acid-labile leach-enhancing material, and a method of forming a leached PDC using an acid-labile leach-enhancing material. The present disclosure further includes drill bits using PDCs formed suing an acid-labile leach-enhancing material.

A method of making a polycrystalline diamond compact includes forming a first layer of polycrystalline diamond precursor materials comprising diamond particles and a first concentration of catalyst, forming a second layer of polycrystalline diamond precursor materials comprising diamond particles and a second concentration of catalyst, and placing a layer of an infiltrant material in the proximity of the first or the second layer of polycrystalline diamond precursor materials. The second concentration of catalyst is greater than the first concentration of catalyst. The infiltrant material is a catalyst. The first layer and the second layer are sintered under high-pressure high-temperature conditions in the presence of the infiltrant material to form the polycrystalline diamond compact. At least a portion of the catalyst is leached from the polycrystalline diamond compact.

A mill-drill cutter for an earth boring bit includes a cutting structure secured to a substrate. The cutting structure has a drilling edge, and the substrate has a milling edge. The substrate is configured to be received in a cutter pocket of the earth boring bit. The drilling edge of the cutting structure is disposed radially internal to the milling edge of the substrate.

A mill-drill cutter for an earth boring bit includes a cutting structure secured to a substrate. The cutting structure has a drilling edge, and the substrate has a milling edge. The substrate is configured to be received in a cutter pocket of the earth boring bit. The drilling edge of the cutting structure is disposed radially internal to the milling edge of the substrate.

A drill bit including a body having a face and a plurality of blades disposed on the face of the body. Each of the plurality of blades may have a row of cutters disposed thereon, and the rows of cutters may collectively define a cutting profile of the drill bit. At least some of the cutters along the cutting profile may have alternating positive back rake angles. The difference between a majority of back rake angles on adjacent cutters along the cutting profile may be less than 20°.

A directional drilling assembly includes a downhole piston and an uphole piston. A downhole piston diameter of the downhole piston is smaller than an uphole piston diameter of the uphole piston diameter. This may allow the downhole piston and/or the uphole piston to be located closer to the bit, thereby improving the maximum DLS of the system.

Roller cutters comprise a diamond-bonded body joined to an infiltration substrate. An extension is joined to the substrate and includes first section having a diameter sized the same as the substrate, and an integral second section having a diameter smaller than the substrate. The extension is joined to the substrate during an HPHT process. The first section has a thickness greater than that of the infiltration substrate. The second section has an axial length greater than the combined thickness of the substrate and the first section. The extension has a strength and/or toughness greater than the substrate as a result of its material composition, e.g., the amount of binder phase material and/or the size of hard phase material. The roller cutter is rotatably disposed within a pocket internal cavity, wherein the pocket is attached to a

Roller cutters comprise a diamond-bonded body joined to an infiltration substrate. An extension is joined to the substrate and includes first section having a diameter sized the same as the substrate, and an integral second section having a diameter smaller than the substrate. The extension is joined to the substrate during an HPHT process. The first section has a thickness greater than that of the infiltration substrate. The second section has an axial length greater than the combined thickness of the substrate and the first section. The extension has a strength and/or toughness greater than the substrate as a result of its material composition, e.g., the amount of binder phase material and/or the size of hard phase material. The roller cutter is rotatably disposed within a pocket internal cavity, wherein the pocket is attached to a

A drill bit includes a shank having a threaded coupling formed at an upper end thereof; a bit body mounted to a lower end of the shank and having a plenum; a gage section forming an outer portion of the drill bit; a cutting face forming a lower end of the drill bit and including: a core receptacle formed at a center of the cutting face, operable to receive a core of earth, and including: a concave core cutter mounted to a bottom of the bit body; and a core port extending from the plenum through the bottom of the bit body and operable to discharge drilling fluid onto the core and core cutter; a plurality of blades protruding from a bottom of the bit body and extending from a periphery of the core receptacle to the gage section; and a plurality of leading cutters mounted along each blade.