The invention relates to a composite shock absorber for a polycrystalline diamond compact bit, comprising a drilling tool body having a water inlet, an impact body having a water outlet and forming a shock absorption cavity, a disc spring group having an annular pressing sleeve, a cylindrical torsion bar spring which has an external thread and a spline, is connected to the drilling tool body through threads and extended into an impactor and connected thereto through the spline, and the annular pressing sleeve, wherein bit vibration impact force is transmitted therebetween through a torsion transmission joint, and a bearing group is arranged between the lower end surface of the annular pressing sleeve and an annular step of the impact body. The composite shock absorber can weaken damage of the slippage effect to polycrystalline diamond compact cutting teeth, absorb axial vibration from a drill stem and prolong the service life of the bit.

A superhard polycrystalline construction comprises a body of polycrystalline superhard material comprising a superhard phase, and a second phase dispersed in the superhard phase, the superhard phase comprising a plurality of inter-bonded superhard grains. The second phase comprises particles or grains that do not chemically react with the superhard grains, and/or do not inter-grow, and form between around 1 to 30 volume % or wt % of the body of polycrystalline superhard material.

A superhard polycrystalline construction comprises a body of polycrystalline superhard material comprising a superhard phase, and a second phase dispersed in the superhard phase, the superhard phase comprising a plurality of inter-bonded superhard grains. The second phase comprises particles or grains that do not chemically react with the superhard grains, and/or do not inter-grow, and form between around 1 to 30 volume % or wt % of the body of polycrystalline superhard material.

An arrangement for generating a resistivity image having a drill bit with cutters configured to be placed within a wellbore, the cutters configured to create further sections of the wellbore upon rotation, the drill bit having an end with threads for engagement, at least one section of drill string connected to the drill bit through a matching set of threads for engagement, a receiver toroid connected to the at least one section of drill string along at least a portion of the drill string, a transmitter toroid connected to the at least one section of drill string and located at least a portion of the drill string away from the receiver toroid, at least one stabilizer connected to the at least one section of drill string, a power source connected to the transmitter toroid and the receiver toroid, an electrode arrangement placed at the drill bit, wherein the electrode arrangement is electrically connected to the drill bit through a non-linear circuit element and a computer arrangement connected to the receiver toroid.

Methods of forming a polycrystalline diamond compact for use in an earth-boring tool include forming a body of polycrystalline diamond material including a first material disposed in interstitial spaces between inter-bonded diamond crystals in the body, removing the first material from interstitial spaces in a portion of the body, selecting a second material promoting a higher rate of degradation of the polycrystalline diamond compact than the first material under similar elevated temperature conditions and providing the second material in interstitial spaces in the portion of the body. Methods of drilling include engaging at least one cutter with a formation and wearing a second region of polycrystalline diamond material comprising a second material faster than the first region of polycrystalline diamond material comprising a first material. Polycrystalline diamond compacts and earth-boring tools including such compacts.

Methods of forming a polycrystalline diamond compact for use in an earth-boring tool include forming a body of polycrystalline diamond material including a first material disposed in interstitial spaces between inter-bonded diamond crystals in the body, removing the first material from interstitial spaces in a portion of the body, selecting a second material promoting a higher rate of degradation of the polycrystalline diamond compact than the first material under similar elevated temperature conditions and providing the second material in interstitial spaces in the portion of the body. Methods of drilling include engaging at least one cutter with a formation and wearing a second region of polycrystalline diamond material comprising a second material faster than the first region of polycrystalline diamond material comprising a first material. Polycrystalline diamond compacts and earth-boring tools including such compacts.

Embodiments disclosed herein relate to a method for analyzing a fixed cutter drill bit, said method including selecting a cutter; selecting an earth formation; simulating drilling performance of the fixed cutter bit having at least once cutter thereon; performing finite element analysis using outputs from the simulating; and outputting stress on the at least one cutter.

Embodiments disclosed herein relate to a method for analyzing a fixed cutter drill bit, said method including selecting a cutter; selecting an earth formation; simulating drilling performance of the fixed cutter bit having at least once cutter thereon; performing finite element analysis using outputs from the simulating; and outputting stress on the at least one cutter.

A cutting element includes a substrate and a volume of polycrystalline diamond (PDC) on the substrate. The PDC volume has a front cutting face, a lateral side surface, and a cutting edge between the front cutting face and the lateral side surface. The cutting edge has a cutting apex and extends between a first side flat surface and a second side flat surface. The side flat surfaces are disposed on opposing sides of the cutting apex. The cutting edge further includes a first chamfer surface and a second chamfer surface, which are located adjacent to one another and oriented at a first angle relative to one another at the cutting apex. The cutting edge includes one of: an arcuate edge having a radius of curvature; and a linear edge having discrete linear edges adjacent one another and separated by a second angle.

Cutters for a downhole drill bit can be formed by providing a catalyst-free synthesized polycrystalline diamond (PCD) having a cross-sectional dimension of at least 8 millimeters; providing a substrate comprising tungsten carbide; and attaching the synthesized PCD to the substrate comprising tungsten carbide to form a PDC cutter.