摘要:
A bi-center downhole drilling bit is disclosed, which bit includes a body defining proximal and distal ends, where said distal end defines a pilot and a reamer where the reamer defines a first cutting face having a selected diameter “d” and the pilot defines a second cutting face having a selected diameter less than “d”, where each the first and second cutting faces includes upsets defining proximal and distal surfaces where the distal surfaces are provided with cutting elements and the proximal surfaces are provided with one or more gauge pads.
摘要:
A bi-center bit adapted to be consecutively used in casing and in formation without the need of removing the bit from the borehole, the bit comprising a bit body defining a proximal end adapted for connection to a drill string, a distal end and a pass-through gauge, where the distal end defines a pilot bit and an intermediate reamer section, where each the pilot and reamer section define a cutting face. A plurality of cutting or wear elements are situated on cutting blades disposed about the cutting face of the pilot and reamer sections. Cutting or wear elements are disposed on one or more of the blades which extend to or are proximate to the pass-through gauge define an angle between the line of contact on the cutting or wear element and the material to be drilled of between 5-45 degrees.
摘要:
An improved bi-center bit with improved directional stability and wear resistance is disclosed, which bit optimally utilizing a plurality of shaped PDC cutting elements selectively situated about the cutting surfaces of the pilot and the reamer to produce a minimal force imbalance, where further the pilot bit and the reamer are force balanced to further reduce imbalance in the operation of the tool.
摘要:
A drag bit having a plurality of blades or ribs on its end face has one or more pockets milled into the top surfaces of said blades using a ball-nosed end mill to create a plurality of pockets, each having a spherical or a semi-spherical first end and a second end having a semicircular configuration that intersects with the leading edge face of the rib. A bullet-shaped cutting structure having a spherical first end is brazed into each of the pockets. During the manufacturing process, a pin is brazed into cooperating first and second semicircular receptacles in the spherical end of the cutter and in the semi-spherical end of the pocket, respectively, to prevent the cutter assembly from being pushed up out of the pocket during the drilling operation. In an alternative embodiment, a slot is milled into the top surface of the rib to allow use of a ball-nosed end mill having a reduced diameter shank sized to pass through the slot. In yet another embodiment, a tungsten carbide button or insert is position at the gauge diameter to reduce impact on the gauge diameter cutter in each of the ribs. Cutter assemblies are disclosed having a variety of orifices in the PDC cutter face to function as chip breakers during the drilling operation.
摘要:
An expandable eccentric reamer for placement in a drill string up-hole of a conventional drill bit. The reamer blade is actuated by drilling fluid pressure to radially extend to a drill out diameter greater than a pass-through diameter. The reamer body is shaped to have an eccentric outer surface configuration to accommodate the reamer blade therein. The reamer blade acts as a piston arm in response to drilling fluid pressure and moves along a shaft anchored in a hump region that forms an eccentricity in the outer surface configuration of the body. The reamer blade has an outer edge configuration that positions the cutters thereon to prevent them from engaging a casing of a well borehole upon deployment.
摘要:
The invention is directed to a bi-center drilling tool adapted to fit within and drill through a casing shoe without damage to the surrounding casing. In one embodiment, the tool comprises a bit body having a proximal and a distal end where the distal end defines a pilot bit and an intermediate reamer section, where each the pilot and reamer sections define a bit face including primary and secondary cutting blades and cutting elements disposed on said blades. In this embodiment, the cutting or wear elements disposed on the one or more cutting blades which extend to or are proximate to the pass-through gauge define a selected angle between the line of contact on the cutting or wear elements and the material to be drilled.
摘要:
Subterranean drill bits and particularly to nozzle features to be incorporated in subterranean bits. In one embodiment, the nozzle assembly of the invention defines a wear resistant structure which extends upstream from the terminus of the transition area. In another embodiment, nozzle assemblies are arranged about the transition area at low angles so as to minimize flow turbulence.
摘要:
A strainer is shown for use with a downhole tool through which drilling fluid is circulated during the drilling of deep oil wells and the like. The strainer provides a plurality of narrow slots which prevent the passage of material therethrough that might be entrained with the fluid and which otherwise would plug ports or nozzles or restrict flow passages below the strainer.