摘要:
A rotary drag bit including exterior features to control the depth of cut by cutters mounted thereon, so as to control the volume of formation material cut per bit rotation as well as the torque experienced by the bit and an associated bottomhole assembly. The exterior features preferably precede, taken in the direction of bit rotation, cutters with which they are associated, and provide sufficient bearing area so as to support the bit against the bottom of the borehole under weight on bit without exceeding the compressive strength of the formation rock. The exterior features may be oriented and configured to function optimally at a predicted rate of penetration, or range of rates, at which the bit may be operated, such rate or rates being further optionally maximized in softer formations in light of the ability of the bit to hydraulically clear a maximum volume of formation cuttings to prevent so-called bit balling.
摘要:
Cutting elements for use in a rotary drill bit are configured to facilitate positioning of the cutting elements at a positive rake angle with respect to the formation to enhance compressive stresses in the cutting element and to reduce cutting loads on the cutting elements. The cutting element generally comprises a three-dimensional superabrasive cutting member having a leading edge and a three-dimensional arcuate scoop-like surface which conveys formation cuttings away from the cutting element. The cutting element may also be formed to a substrate or backing. A drill bit suitable for use of the cutting elements of the invention is disclosed which includes passageways and internal fluid passages for enhancing the conveyance of formation cuttings away from the leading edge of the cutting element. A method of drilling earthen formations with a drill bit incorporating at least one cutting element comprising a three-dimensional superabrasive cutting member having a leading edge and a three-dimensional arcuate scoop-like surface which conveys formation cuttings away from the cutting element is also disclosed.
摘要:
An improved stud design for an earth boring drill bit is disclosed preferably using materials of different hardness and toughness layered to provide maximum resistance to surface abrasion coupled with excellent structural properties including high strength with maximum fracture toughness. The bit body is conventionally attached to a drill string, and has a crown and gage portion. The studs preferably include a core, made of steel or other material having high fracture toughness, covered at least in part with a hard, abrasion resistant material such as tungsten carbide. Each stud is secured to a socket in the bit body by means of brazing or other suitable means such as a press fit. The cutting element is brazed to a mounting face of the stud prior to affixation of the stud to the bit body and is preferably comprised of a polycrystalline diamond compact adhered to a backing layer of tungsten carbide.
摘要:
A cutting element and drill bits so equipped particularly suited for drilling subterranean formations exhibiting a superabrasive cutting face with at least a portion of extremely low surface roughness, by way of example on the order of a polished, mirror-like finish. The cutting face includes a peripheral cutting edge adjacent the low surface roughness portion of the cutting face for engaging a subterranean formation, the cutting edge being of sharp configuration and essentially defining a line of contact with the formation lying between the cutting face and a side surface of the cutting element extending rearwardly therefrom. In certain formations, particularly soft, plastic formations, the drill bits equipped with the inventive cutting element may be employed as a system and method with drilling fluids modified to maintain the integrity of formation cuttings by stabilizing and locking in reactive clays present in the rock to inhibit bit balling and facilitate hydraulic cuttings removal from the bit face.
摘要:
A drilling apparatus having cuttings removal structure to reduce balling thereof comprising an apparatus body having a connection thereon, and structure for contacting cut potions of the earth formation. The contacting structure may include chip breakers, flexible cables, rotating nozzle assemblies, rotating turbine wheel assemblies, rotating vane assemblies, flails or combinations of these. The apparatus may include elastomeric portions and/or movable potions. The drilling apparatus may comprise a drill bit, drilling stabilizer, drill collar, reamer, downhole motor, etc.
摘要:
A drill bit and method in which polycrystalline diamond cutters mounted on a bit crown cut formation chips akin to the manner in which a grater cuts cheese. Chips in impermeable or plastic formations are extruded by the cutters into cavities internal to the bit via slots adjacent each cutter. Drilling fluid circulates internally of the bit from the drill string and into the annulus above that portion of the bit bearing cutters. In one embodiment, the portion of the bit body upon which the crown is formed is made of an elastomer which is pressurized into sealing engagement with the bottom of the borehole thereby further sealing freshly cut formation from drilling fluid.
摘要:
A cutting element for a rotary drill bit for subterranean drilling, including a substantially planar table of superhard material having a cutting face and a cutting edge. The table may be reinforced against bending with one or more strut portions extending from the rear of the table to the rear of the substrate and at least partially across the cutting element. The strut portions may be integral with the diamond table, or separately fabricated and of another material. The strut portions, in addition to or in lieu of providing stiffness to the superhard table, may also serve to enhance heat transfer away from the cutting face and cutting edge of the superhard table. The structure supporting the cutting element on the drill bit and the body of the drill bit itself may be additionally configured to include structures to facilitate heat transfer away from the superhard table.
摘要:
A rotary drag bit for drilling hard rock formations with substantially planar PDC cutting elements having diamond tables backed by substrates which flare or taper laterally outwardly and rearwardly of the cutting edge of the diamond table. A cutting structure defining a "lipped" cutting edge is also disclosed.
摘要:
Various embodiments of the invention relate to bearing assemblies, apparatuses and motor assemblies that include geometric features configured to impart a selected amount of heat transfer and/or hydrodynamic film formation. In an embodiment, a bearing assembly may include a plurality of superhard bearing pads distributed circumferentially about an axis. At least some of the plurality of superhard bearing pads may include a plurality of sub-superhard bearing elements defining a bearing surface. At least some of the plurality of sub-superhard bearing elements may be spaced from one another by one or more voids to impart a selected amount of heat transfer and hydrodynamic film formation thereon during operation. The bearing assembly may also include a support ring that carries the plurality of superhard bearing pads. In addition, at least a portion of the sub-superhard bearing elements may extend beyond the support ring.
摘要:
In an embodiment, a bearing assembly may include a support ring to which one or more superhard bearing elements may be mounted. The support ring may include one or more relief features configured to reduce residual stresses in the superhard bearing elements that are induced by brazing the superhard bearing elements to the support ring, operational loads, other processes, or combinations of the foregoing. Reducing the residual stresses in the superhard bearing elements may help prevent damage to the superhard bearing elements. The bearing assembly may be used in subterranean drilling systems and/or other types of systems.