Displacements for use in forming at least a portion of a bit body of an earth-boring rotary drill bit may comprise a machineable material portion configured to form an integral machineable portion of the bit body. Such displacements may optionally also include a sacrificial material portion. Bit bodies resulting from the use of such displacements may comprise a main body comprised of a particle-matrix composite material and a plurality of integral machineable portions. Earth-boring rotary drill bits may include such bit bodies. Methods of manufacturing such bit bodies, and methods of manufacturing earth-boring rotary drill bits utilizing displacements are also disclosed.

A method for evaluating a downhole working condition of a PDC bit includes: performing an indoor test, including performing a drilling test in different full-sized cores by using the PDC bit with different degrees of abrasion and balling under condition of given WOB and rotational speed, to acquire change characteristics of a WOB, a rotational speed, a torque, a ROP and a bit vibration of the PDC bit in different time domains; improving and perfecting an existing prediction model and evaluation method for the downhole working condition through data obtained by the test to obtain the method; reading parameters of the WOB, the rotational speed, the torque and the ROP in real time during drilling; determining the downhole working condition of the PDC bit by using the method in the improving and perfecting.

Embodiments of the invention relate to polycrystalline diamond compacts (“PDCs”) including a polycrystalline diamond (“PCD”) table having a structure for enhancing at least one of abrasion resistance, thermal stability, or impact resistance. In an embodiment, a PDC includes a PCD table. The PCD table includes a lower region including a plurality of diamond grains exhibiting a lower average grain size and at least an upper region adjacent to the lower region and including a plurality of diamond grains exhibiting an upper average grain size. The lower average grain size may be at least two times greater than that of the upper average grain size. The PDC includes a substrate having an interfacial surface that is bonded to the lower region of the PCD table. Other embodiments are directed methods of forming PDCs, and various applications for such PDCs in rotary drill bits, bearing apparatuses, and wire-drawing dies.

Embodiments of the invention relate to polycrystalline diamond compacts (“PDCs”) including a polycrystalline diamond (“PCD”) table having a structure for enhancing at least one of abrasion resistance, thermal stability, or impact resistance. In an embodiment, a PDC includes a PCD table. The PCD table includes a lower region including a plurality of diamond grains exhibiting a lower average grain size and at least an upper region adjacent to the lower region and including a plurality of diamond grains exhibiting an upper average grain size. The lower average grain size may be at least two times greater than that of the upper average grain size. The PDC includes a substrate having an interfacial surface that is bonded to the lower region of the PCD table. Other embodiments are directed methods of forming PDCs, and various applications for such PDCs in rotary drill bits, bearing apparatuses, and wire-drawing dies.

A drill bit for cutting formation comprises a bit body, a plurality of cutters, a plurality of blades with pockets to accommodate the cutters respectively. Each of the plurality of cutters has an ultra-hard layer, two side facets extending obliquely inward from the substrate to a top surface of the ultra-hard layer, a convex portion between the two side facets. The convex portion comprises a transition surface and the transitional surface is convex as it extends between adjacent the two side facets. The curvature of the transitional surface varies along the cutter axis with the curvature at the cutting edge larger than the curvature of the cutter circumferential surface.

A metal matrix composite composition includes tungsten carbide in an amount of 45 wt % to 72 wt % of the composition. In addition, the composition includes a binder in an amount of 28 wt % to 55 wt % of the composition. The binder includes nickel in an amount of at least 99 wt % of the binder.

A cutting element may include a substrate; and an ultrahard layer on the substrate, the ultrahard layer including a non-planar working surface that is surrounded by a peripheral edge having a varying height around a circumference of the cutting element, the working surface also having: a plurality of cutting crests extending from an elevated portion of the peripheral edge across at least a portion of the working surface; at least one valley between the plurality of cutting crests; and a canted surface extending laterally from each of the outer plurality of cutting crests towards a depressed portion of the peripheral edge, a height between the depressed portion and the elevated portion being greater than a height between the elevated portion and the valley.

A cutting element may include a substrate; and an ultrahard layer on the substrate, the ultrahard layer including a non-planar working surface that is surrounded by a peripheral edge having a varying height around a circumference of the cutting element, the working surface also having: a plurality of cutting crests extending from an elevated portion of the peripheral edge across at least a portion of the working surface; at least one valley between the plurality of cutting crests; and a canted surface extending laterally from each of the outer plurality of cutting crests towards a depressed portion of the peripheral edge, a height between the depressed portion and the elevated portion being greater than a height between the elevated portion and the valley.

A method includes simulating a cutting tool drilling an earth formation by incrementally rotating the cutting tool at a plurality of time intervals, determining a true trajectory of a cutting element disposed on the cutting tool for the duration of the plurality of time intervals, and determining a dynamic work profile for the cutting element based on the true trajectory and a force acting on the cutting element at each time interval.

A method includes simulating a cutting tool drilling an earth formation by incrementally rotating the cutting tool at a plurality of time intervals, determining a true trajectory of a cutting element disposed on the cutting tool for the duration of the plurality of time intervals, and determining a dynamic work profile for the cutting element based on the true trajectory and a force acting on the cutting element at each time interval.