Abstract: A bit having improved dropping tendencies includes a first plurality of cutters in an active region and a second plurality of cutters in a passive region. The second plurality of cutters has unique radial positions with respect to the first plurality of cutters. The first and the second pluralities of cutters also have cutting tips that extend to the primary cutting profile of the bit. A third plurality of cutters is located in the passive region with cutting tips positioned recessed from the primary cutting profile. A forth plurality of cutters is positioned as back up cutters in the active, region and includes cutters positioned in radial locations such that they overlap, when viewed in rotated profile, with cutters in the third plurality of cutters. The fourth plurality of cutters has cutting tips positioned to extend to the primary cutting profile. The cutters on the bit are arranged such that an imbalance force vector exists on the bit when used to drill though earth formation.

Abstract: In an embodiment, a drill bit for drilling a borehole comprises a bit body having a bit axis and a bit face. In addition, the drill bit comprises a primary blade extending radially along the bit face. Further, the drill bit comprises a plurality of primary cutter elements mounted to the primary blade. The primary blade is free of backup cutter elements. Still further, the drill bit comprises a secondary blade extending radially along the bit face. Moreover, the drill bit comprises a plurality of primary cutter elements mounted to the secondary blade. In addition, the drill bit comprises a first plurality of backup cutter elements mounted to the secondary blade in a first backup row that trails the primary row. Further, the drill bit comprises a second plurality of backup cutter elements mounted to the secondary blade in a second backup row that trails the first backup row.

Abstract: A drill bit for drilling a borehole in earthen formations comprises a bit body including a cone region, a shoulder region, and a gage region. In addition the bit comprises a first primary blade and a second primary blade. Further, the bit comprises a plurality of primary cutter elements mounted to the first primary blade in different radial positions. Still further, the bit comprises a plurality of primary cutter elements mounted to the second primary blade in different radial positions. Moreover, a first primary cutter element of the plurality of primary cutter elements on the first primary blade and a first primary cutter element of the plurality of primary cutter elements on the second primary blade are each positioned in the cone region and are redundant. The shoulder region has a total cutter redundancy percentage that is less than a total cutter redundancy percentage in the cone region.

Abstract: The present invention provides a bit with cutting structures or inserts that include diamond particles, in which the diamond-impregnated inserts are surrounded by substantially diamond-free support members. The diamond-impregnated inserts are manufactured separately from the bit body. Once formed, the diamond-impregnated inserts are affixed to the substantially diamond-free support members on bit body by brazing or other means of attachment. The total thermal exposure of the diamond particles during manufacture in accordance with the present invention is significantly lower than the total manufacturing-related thermal exposure in previously known diamond-impregnated cutting structures. Furthermore, the substantially diamond-free support members allow the bit to continue cutting through a formation without an increased contact area, as experienced by bits with diamond-impregnated ribs. Thus, the operating life of the cutting structures, and therefore the life of the bit itself, is increased.

Abstract: Cutting elements are provided having multiple diameter sections. Also provided are bits incorporating such cutting elements.

Abstract: The invention provides a fixed cutter drill bit for drilling through unconsolidated, highly abrasive formations. The bit includes a bit body having a cutting face and a side portion. The bit body comprising carbide matrix material. A plurality of blades azimuthally spaced about the cutting face and a plurality of cutters disposed along the blades. At least one gage pad is disposed along a side of the bit body and includes wear resistant gage elements formed of a material more wear resistant than the matrix material forming a portion of the gage pad. The wear resistant elements have a rounded surface and are embedded in gage pad material proximal a leading edge of the gage pad to provide a rounded wear-resistant edge or surface proximal the leading edge.

Abstract: The invention provides a fixed cutter drill bit for drilling through unconsolidated, highly abrasive formations. The bit includes a bit body having a cutting face and a side portion. The bit body comprising carbide matrix material. A plurality of blades azimuthally spaced about the cutting face and a plurality of cutters disposed along the blades. At least one gage pad is disposed along a side of the bit body and includes wear resistant gage elements formed of a material more wear resistant than the matrix material forming a portion of the gage pad. The wear resistant elements have a rounded surface and are embedded in gage pad material proximal a leading edge of the gage pad to provide a rounded wear-resistant edge or surface proximal the leading edge.

Abstract: The present invention provides a bit with cutting structures or inserts that include diamond particles, in which the diamond-impregnated inserts are surrounded by substantially diamond-free support members. The diamond-impregnated inserts are manufactured separately from the bit body. Once formed, the diamond-impregnated inserts are affixed to the substantially diamond-free support members on bit body by brazing or other means of attachment. The total thermal exposure of the diamond particles during manufacture in accordance with the present invention is significantly lower than the total manufacturing-related thermal exposure in previously known diamond-impregnated cutting structures. Furthermore, the substantially diamond-free support members allow the bit to continue cutting through a formation without an increased contact area, as experienced by bits with diamond-impregnated ribs. Thus, the operating life of the cutting structures, and therefore the life of the bit itself, is increased.

Abstract: A drill bit is disclosed which includes a bit body having a plurality of ports therein arranged to provide a flow path between an interior of a drill string and the exterior of the bit body. At least one flow relief is disposed in one of the ports. The at least one flow relief is adapted to provide an increase in total flow area of the bit upon application to the bit of a selected fluid flow condition. A method for changing a total flow area of a drill bit is also disclosed, which includes pumping drilling fluid through the drill bit and operating a flow relief disposed in the bit to change the total flow area of the bit.

Abstract: A drill bit is disclosed which includes a bit body having a plurality of ports therein arranged to provide a flow path between an interior of a drill string and the exterior of the bit body. At least one flow relief is disposed in one of the ports. The at least one flow relief is adapted to provide an increase in total flow area of the bit upon application to the bit of a selected fluid flow condition. A method for is also disclosed changing a total flow area of a drill bit, which includes pumping drilling fluid through the drill bit and operating a flow relief disposed in the bit to change the total flow area of the bit.

Abstract: A self-centering drill bit includes a head portion having a plurality of polycrystalline diamond compact cutting elements arranged in blades that extend outwardly away from a surface of the bit. A cavity is centrally located on the head portion and is formed between adjacent blade ends. The cavity includes wall portions defined by the blade end portions. The cavity serves to house a core portion that is formed during drilling operation of the bit. The head portion is balanced to form and transmit a force from a designated wall portion to the core portion within the cavity. At least the designated wall portion includes a low friction abrasion resistant surface. The cavity includes a rigid element extending outwardly away from the head portion to reduce the core within the cavity upon contact. The force transmitted to the core portion causes a countering force to be imposed by the core to the wall portion that keeps the bit aligned with its rotational axis and, thus prevents whirling.

Abstract: A diamond drag bit is disclosed that utilizes stud type PDC cutters that have dome shaped polycrystalline diamond depth of penetration limiters fused to the tungsten carbide surface trailing the PDC compact disc. This cutter penetration limiting diamond dome surface acts as an impact or shock absorber to minimize the impact damage to the PDC cutter when drilling laminated hard and soft rock formations.

Abstract: A polycrystalline diamond compact (PDC) drag bit cutter is disclosed that provides more clearance between the cutter's drilling edge and the drag bit body mounting blade. This allows for more efficient hydraulic cooling and cleaning of the cutters, thereby achieving faster drilling rates. A cylindrical carbide cutter base end having an off-set asymmetric diamond cutting end provides for less interference of the bit head surfaces and the rock formation being drilled, thereby reducing detrimental heat and also allowing a greater depth of penetration of the cutter.

Abstract: A drag bit for soft, sticky formations is disclosed with a new fluid dynamics control mechanism that minimizes "bit-balling". Multiple blades carrying PDC cutters have tapered back sides to achieve greater velocity through the fluid channels. Multiple jet nozzles in each fluid channel create interacting vortices that produce extremely turbulent flow thereby minimizing the coagulation and deposition of the hydrated clay cuttings on the bit cutting surfaces.

Abstract: A drag bit for soft formation is disclosed which consists of a new cutting mechanism. The drag bit face forms one or more pairs of radially disposed ridges separated by a valley whereby a leading ridge supports multiple rounded projections and the following ridge supports multiple positive rake angle cutters. The rounded projection elements move aside an elastic earth formation and the separated and trailing cutters clip off the dislodged formation to advance the bit in a borehole.

Abstract: A drag bit mold fabricated from high temperature resisting material is machined to accept cylindrically shaped polycrystalline diamond cutters (PCD) having tungsten carbide bodies. Each of the multiple PCD matrix pockets in the mold is formed by two independent non-parallel end mill passes. The first end mill cut defines the PCD cutter position in the cutting face of the matrix diamond drag bit. The second end mill cut superimposed over the first end mill pocket creates a surrounding pocket which fills with powder metallurgy matrix material to provide support for the cylindrical cutter. The second end mill is only slightly larger than the first end mill to minimize the size of the insert securing fillet subsequently formed thus assuring that the fillet will not interfere with the depth of penetration of each of the PCD cutters.