Abstract: An enlarged diamond table for use as a cutter in rotating drill bits is provided by disposing a plurality of thermally stable or leached polycrystalline diamond (PCD) rod-like elements within a matrix body. In one embodiment the matrix body is impregnated with diamond grit and completely fills the interstitial spaces between the plurality of PCD elements. Generally, the PCD elements have their longitudinal axes arranged in a mutually parallel configuration. The bundle of rod-like diamond elements are in one embodiment in a compact touching array and in another embodiment in a spaced-apart array. In the illustrated embodiment, a bundle of rod-like diamond elements are disposed so that their end surfaces are exposed on the cutting face of the cutting slug. The slug is then in turn mounted on a stud or directly infiltrated into a matrix body bit.

Abstract: The present invention relates to a method and apparatus for navigational driling in earth formations, the apparatus including a downhole drilling assembly having a drill bit driven by a downhole motor and a deflection element or elements in the assembly for imparting an angle of deflection to the drill bit relative to the drill string above the drilling assembly. At least two stabilization points for the drilling assembly in the borehole are used, with the drill bit, to define an arcuate path for the drilling assembly when the downhole motor is operating but the drill string is not rotating. When the drill string is rotated, the drilling assembly drills a substantially straight or linear borehole.

Abstract: A rotary drill bit for drilling earth formations is provided and includes a bit shank, a hard metal matrix secured to a blank and cutting elements on the exterior face thereof. The matrix includes a displacement material having a different composition than the matrix material within the matrix. The displacement material is preferably less expensive than the matrix material and also has different material properties. The resulting bit may be custom-engineered for toughness, ductility, and impact resistance.

Abstract: A diamond cutter for use in a drill bit having a geometric size and shape normally characterized by unleached diamond product, such as STRATAPAX diamond cutters, can be fabricated by assembling a plurality of prefabricated leached polycrystalline diamond (PCD) elements in an array in a cutting slug. A cutting slug is formed of matrix material which in one embodiment is impregnated with diamond grit. The cutting face of the cutting slug is characterized by exposing at least one surface of each of the PCD elements disposed therein. The diamonds may be set within the cutting slug either in a compact touching array or in a spaced-apart relationship. More than one type of array may also be employed within a single cutting slug. The PCD elements can assume a variety of polyhedral shapes such as triangular prismatic elements, rectangular elements, hexagonal elements and the like. The plurality of diamond elements and the cutting slug are fabricated using hot pressing or infiltration techniques.

Abstract: A drill bit offering improved steerability. Drill bits include gage sections which are adapted to facilitate deflection of the bits within a borehole to facilitate navigational or directional drilling. The gage portions of the bit may be arranged in an arcuate path around a portion of the periphery of the bit. Also, the bit portions may be spaced and adapted to serve, at least in part, as fulcrums, to facilitate deflection of the bit and the bringing of gage cutting portions of the bit in contact with the sidewalls of the borehole.

Abstract: A core drilling tool for drilling rock in underground soil formations which includes an outside pipe and an inside pipe therein that can be conveyed separately to the surface. The inside pipe includes a core-receiving receptacle at its lower end, and at its upper end is provided with a measurement unit for on-site acquisition, processing and storage of data, such as borehole, core and/or drilling process parameters.

Abstract: Pulse rates, rise and fall times of pulses and lifetimes of mud pulsing valves are substantially increased by providing a valve with a plurality of openable ports which simultaneously open and close to provide a collective flow path of the mud through the valve. By employing a plurality of ports, instead of one port, the time rate of change in the flow area, as the plurality of ports opens and closes, is substantially greater in the case of a single port. As a result, mud velocity falls much more quickly and the abrasion damage within the mud valve is less. The rate of change of the flow area on opening and closing is further increased by providing noncircular ports. In particular, trapezoidal ports are utilized so that they open across a corresponding straight edges. A plurality of such trapezoidal ports may be utilized to increase the rate of change of flow area with time to an even greater extent.

Abstract: A rotary drill bit and process of fabrication in which internal fluid passages and watercourses of the bit are lined with a hard metal matrix material which renders the fluid passages more resistant to the erosive forces of the drilling fluid is provided. Also, elements such as lands for cutter element mountings, sockets, ridges, shoulders and the like on the exterior surface of the bit can be fabricated of a hard abrasion and erosion resistant material and incorporated into the bit body during fabrication. The process includes the steps of providing a hollow mold for molding at least a portion of the drill bit and positioning one or more flexible or moldable tubular elements which correspond to the internal watercourses in the mold. The elements are fabricated of a hard metal powdered material dispersed in a polymeric binder. A bit blank is then positioned at least partially within the mold and the mold packed with a metal matrix material which forms the body of the bit.

Abstract: The subject drill bits include a body member with cutter blades having a generally parabolic bottom profile. The cutter blades each include a diamond cutting face which increases in vertical height generally as a function of increased distance from the center line of the bit. The increased height allows the bits to provide a desired total diamond cutting volume at each radius of the bit, while allowing the diamond contact area to remain generally constant as the bit wears.

Abstract: An improved rotating drag bit for cutting plastic, sticky, water reactive and shale formations is devised by providing a plurality of large diamond cutters having a circular cutting face in excess of three quarter inch in diameter. Each large cutter is provided with at least one hydraulic nozzle which in turn provides a directed hydraulic flow at the corresponding cutter face. The directed hydraulic flow is positioned to apply a force to the chip which tends to peel the chip away from the cutter face. In addition, the hydraulic flow is positioned with respect to the chip so as to apply on off-center torque to the chip which is used to peel the chip away from the cutter face and toward the gage of the bit. In particular, the nozzle defines a jet which is characterized by a direction and velocity of hydraulic fluid determined by the jet characteristics. The core is generally symmetric about its longitudinal axis and has a length along the longitudinal axis and width perpendicular thereto.

Abstract: An apparatus for producing pressure pulses in an oil well fluid medium is established which includes a main valve member moveable relative to a supporting member by a pressure gradient between two flow channels. The main valve body is longitudinally moveable relative to the supporting body, and a gap is provided between the two bodies. The gap is opened for fluid flow which prevents the development of dead water zones and the buildup of sedimentary deposits to prevent restriction of movement between the two bodies. The gap includes one or more throttle zones to assist in maintaining the necessary gradient between the two flow channels.

Abstract: An articulated downhole surveying instrument and method for measuring parameters of a wellbore includes one or more laterally flexible coupling sections. The laterally flexible coupling sections are rigid in axial tension and axial compression, and are smaller in cross-section than the surveying instrument housing. A separate housing is used for each component of the surveying instrument, and each component housing is interconnected with the laterally flexible coupling. One or more flexible spacer bars are also provided. The spacer bars and coupling sections enable the assembly to be passed through a short-radius angle wellbore with greatly reduced risk of sticking or hanging up.

Abstract: The apparatus for the generation of pressure pulses in a drilling mud composition which flows downward in a drill string (1) is composed of a valve (V) inside the drill string (1), with a stationary, braced, tubular exterior housing (3), tubular primary valve (4) which can be translated from a lower starting position against the flow direction (2) of the drilling mud composition into an upper operational end position, a stationary, tubular support (5) in a coaxial position inside primary valve (4), and a pilot valve (13), (14) actuated by motor means (15). Exterior housing (3) and primary valve (4) define a constricted segment (29) whose flow cross section can be modified by the position of primary valve (4), and primary valve (4) and the support (5) surround an interior flow channel (21), (12) and (10), which can be opened and closed by outlet orifice (13) of pilot valve (13), (14).

Abstract: A rotary drill bit is provided for boring earth formations which includes a bit blank and a metal matrix secured to the blank. The metal matrix includes a filler material dispersed therein. Cutting elements are mounted on the exterior face of the bit, and substantially all of the exposed internal and external surfaces of the bit are coated with an erosion and abrasion resistant hardfacing material bonded to the metal matrix.

Abstract: An improved rotating drag bit for cutting plastic, sticky, water reactive and shale formations is devised by providing a plurality of large diamond cutters having a circular cutting face in excess of one inch in diameter. Each large cutter is provided with at least one hydraulic nozzle which in turn provides a directed hydraulic flow at the corresponding cutter face. The directed hydraulic flow is positioned to apply a force to the chip which tends to peel the chip away from the cutter face. In addition, the hydraulic flow is positioned with respect to the chip so as to apply an off-center torque to the chip which is used to peel the chip away from the cutter face and toward the gage of the bit. In particular, the nozzle defines a jet which is characterized by a direction and velocity of hydraulic fluid determined by the jet characteristics. The core is generally symmetric about its longitudinal axis and has a length along the longitudinal axis and width perpendicular thereto.

Abstract: An improved bit and method for cutting plastic and sticky rock formations, which tend to cause bit balling, is provided by a drag bit having a cutting face formed of a plurality of generally radially extending open arched blades. Each arched blade is provided with a cutting face and defines a cavity beneath the arched to the bit body. In a preferred embodiment, the cutting elements on the arched blade are a plurality of synthetic polycrystalline diamonds which are cut, sized and shaped to comformally fit with each other so as to present a substantially diamond-only surface as a cutting surface of the bit. Hydraulic nozzles are defined in the bit body beneath and azimuthally behind the arches formed by each blade. The nozzles direct hydraulic flow across the cavity under the arch and across each portion of the cutting face on the arch.

Abstract: A nozzle retention system for a drill bit which includes a nozzle member which is retained by means of a keyway in the bit body. The bit body can include a partially cylindrical bore, truncated by opposing walls to form a lower contact surface within the bit body. The nozzle will be conformed to pass through the bore in a first orientation, and to be retained in the bore and against such contact surface when the nozzle is rotated to the second orientation.

Abstract: A replaceable stud cutter for use in matrix drag bit is provided by furnacing a ductile metallic receptacle within the body of the drag bit as it is fabricated. The metal receptacle is characterized by having a receiving cavity defined therein and by including various mechanisms such as grooves or flares which facilitate retention of the metallic receptacle within the matrix body. The lowermost portion of the receptacle within the matrix body may also be shaped or tapered to allow dense packing of the receptacle adjacent to other receptacles along a given radial line on the bit face. A replaceable cutter is brazed, adhesively bonded and/or mechanically locked within the receiving cavity defined in the metal receptacle. When the replaceable cutter becomes worn through normal use, the mechanical locking elements can be drilled out, the brazing melted or adhesive dissolved to allow insertion of a new replacement cutter without causing any damage or alteration either to the receptacle, matrix body or bit face.

Abstract: A core drilling tool with direct drive consisting of an outer pipe that can be connected to a drilling shaft, a core drilling appliance reciprocally mountable in the outer pipe which in turn includes a core barrel that carries a drill bit and an inner pipe mounted in rotatable relation therewith and for reciprocal movement therewith, and a drilling mud driven motor that is integrally coupled to the core drilling appliance and is secured against rotation in the outer pipe and having reaction faces that are put under pressure to produce a downward axial feed force acting on both the core drilling appliance and the motor, plus a capture device for pulling up the motor together with the core drilling appliance. In order to produce a sufficiently great axial feed force of an adjustable size that is essentially independent of the exposure of the core drilling appliance, the motor is connected to the core drilling appliance to form a common movable unit and devices are provided for adjusting the axial feed force.