The present disclosure provides a fixed-cutter drill bit including a bit body defining a bit rotational axis, a plurality of blades each having an inner end that is radially closer to the bit rotational axis than a remainder of the respective blade, a central bit surface, and a plurality of cutters disposed on the blades and including an innermost cutter located closest among all of the plurality of cutters to the bit rotational axis and having a flattened cutting surface, a cutting arc, and a relief having ends which is located within and interrupts the cutting arc such that the cutting arc includes at least two portions located on opposite ends of the relief. The disclosure also provides a drilling system including the drill bit and a drill string attached to the drill bit and a surface assembly to rotate the drill string and drill bit.

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.

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.

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.

Zonal heating and cooling during the production of matrix drill bits may be achieved with a system that includes a cavity defined within a mold assembly having a central axis; reinforcing particles and a binder material disposed within the cavity; and a plurality of induction coils about a periphery of the mold assembly, each induction coil being spaced from each other along the height of the mold assembly, wherein a first induction coil of the plurality of induction coils is arranged proximal to a portion of mold assembly containing a portion of the reinforcing particles and a second induction coil of the plurality of induction coils is arranged proximal to a portion of the mold assembly containing a portion of the binder material.

Zonal heating and cooling during the production of matrix drill bits may be achieved with a system that includes a cavity defined within a mold assembly having a central axis; reinforcing particles and a binder material disposed within the cavity; and a plurality of induction coils about a periphery of the mold assembly, each induction coil being spaced from each other along the height of the mold assembly, wherein a first induction coil of the plurality of induction coils is arranged proximal to a portion of mold assembly containing a portion of the reinforcing particles and a second induction coil of the plurality of induction coils is arranged proximal to a portion of the mold assembly containing a portion of the binder material.

A drill bit for cutting a hole in a formation. The drill bit has a shank and a crown. The crown has a plurality of crown portions that are spaced about an operative circumference of the drill bit. The shank and crown cooperate to define an interior space that receives water or other drilling fluid. Each crown portion has two longitudinal edges, an outer surface, at least one inner surface and a cutting face. The crown has a base surface that is spaced from the cutting faces of the crown portions and cooperates with the inner surface of each of the two crown portions to define a slot.

A drill bit for cutting a hole in a formation. The drill bit has a shank and a crown. The crown has a plurality of crown portions that are spaced about an operative circumference of the drill bit. The shank and crown cooperate to define an interior space that receives water or other drilling fluid. Each crown portion has two longitudinal edges, an outer surface, at least one inner surface and a cutting face. The crown has a base surface that is spaced from the cutting faces of the crown portions and cooperates with the inner surface of each of the two crown portions to define a slot.

A drilling tool having a body, at least one blade extending from the body, and a first cutting element attached to the at least one blade. The first cutting element includes a cutting face at an opposite axial end from a base, a side surface extending from the base to the cutting face, an edge formed at the intersection between the cutting face and the side surface, and an elongated protrusion formed at the cutting face and extending between opposite sides of the edge. The elongated protrusion has a geometry including a border extending around a concave surface, a face chamfer formed around the border, and sloped surfaces extending between the border and the edge. An edge chamfer is between the face chamfer and the edge.

A cutting element may include a substrate and a volume of polycrystalline diamond material affixed to the substrate at an interface. The volume of polycrystalline diamond may include a front cutting face with at least one substantially planar portion and at least one recess. The at least one recess may extend from a plane defined by the at least one substantially planar portion a first depth into the volume of polycrystalline diamond material in an axial direction parallel to a central axis of the cutting element. The volume of polycrystalline diamond material may comprise a region including a catalyst material. At least one region substantially free of the catalyst material may extend from the at least one substantially planar portion of the front cutting face a second depth into the volume of polycrystalline diamond in the axial direction. Methods of forming cutting elements.