Abstract: The disclosure relates to polycrystalline diamond compact (PDC) drill bits utilized for drilling wellbores.

Abstract: A coolant delivery system which serves to deliver a cooling agent whose purpose is to carry away the heat that is generated in the process of machining a toothed profile by means of a skiving wheel rotating about its rotary axis. The coolant delivery system provides for a delivery path section which, seen in a projection onto a plane extending orthogonal to the rotary axis, is arranged closer to the axis than the toothed profile of the skiving wheel and has a dimensional component in the axial direction.

Abstract: A method of drilling holes comprises ductile mode drilling the holes in a component of a plasma processing apparatus with a cutting tool wherein the component is made of a nonmetallic hard and brittle material. The method comprises drilling each hole in the component by controlling a depth of cut while drilling such that a portion of the brittle material undergoes high pressure phase transformation and forms amorphous portions of the brittle material during chip formation. The amorphous portions of the brittle material are removed from each hole such that a wall of each hole formed in the component has an as drilled surface roughness (Ra) of about 0.2 to 0.8 ?m.

Abstract: Two-centre rotary boring bit for boring wells, comprising, on the one hand, a pilot tool (1) comprising a body of revolution with an axial core (3) and radial blades (4) bearing cutting elements (5) and, on the other hand, an enlarging tool (2) fitted behind the pilot tool and laterally offset therefrom, the pilot tool having, on its front face, a central region (11) that has no cutting elements in order to allow the creation of a core sample (12), said central region being in communication with a cavity (13) situated between two blades (4) of the pilot tool (1) and serving to remove the core sample toward the periphery of the boring bit.

Abstract: A reaming shell for mining is provided. The reaming shell has a shank, and a plurality of pads attached at circumferential intervals from each other to extend lengthwise on an outer periphery of the shank. The reaming shell is coupled to a core bit of a diamond drilling tool for mining. The reaming shell includes a water groove of a recessed shape formed respectively between each adjacent pair of the pads, and extending from a leading edge along a length of the shank.

Abstract: A removable countersink bit comprises a body, a flange, at least one clamp, and a plurality of cutting teeth. The removable countersink bit creates countersink holes for receiving manhole fixtures and the like.

Abstract: A well stimulation tool includes a well stimulation tool mandrel with an axial bore having an internal diameter large enough to permit a backpressure plug to be run through the mandrel into a tubing mandrel, such as a tubing hanger or a casing mandrel, to which the well stimulation tool mandrel is secured. This permits well stimulation to be performed through a tubing string suspended in the well by the tubing mandrel, without requiring wireline services.

Abstract: The invention concerns a method and a device for coring and/or drilling through a wall of a bore hole, to deflect transversely from a longitudinal direction of the hole, further comprising selecting a core barrel (1) equipped with a core bit (3) having an inner gauge bore (5), an arrangement, in the core barrel (1), of an abrasion resistant internal guide (7), which is internal at least with respect to the bore (5) so that the bit (3) can move along guide (7), and is designed to deflect the bit (3) along a desired deflected path, start-up of the coring process with bit (3) and guiding the bit (3) through co-operation between its bore (5) and the guide (7).

Abstract: A drill head carries a plurality of coaxially mounted drill crowns beginning with a first crown and followed by additional drill crowns which, upon rotation, describe concentric envelope circles of successively larger diameters. The first drill crown has cutting elements with a diamond coating with an average particle size of 200-1,000 .mu.m, and the additional drill crowns have cutting elements with a diamond coating with an average particle size of 200-300 .mu.m. The difference in diameter of succeeding drill crowns is successively small. Alignment of the drill crowns in a pilot hole is achieved by guide elements mounted behind the drill crowns and describing an inner envelope circle which is smaller than the outer envelope circle described by the largest drill crown, thereby defining a radial safety gap into which fluid is fed to form a cushion during rotation.

Abstract: The present invention comprises a drilling tool including a retractable pilot drilling unit driven by a fluid operated motor, the motor comprising a stator mounted on the interior of a tubular outer housing and a rotor mounted on the exterior of a tubular inner housing axially supported in said outer housing and rotationally free with respect thereto. The pilot drilling unit is rotationally fixed within the inner housing, but axially moveable therewithin so that pressure of drilling fluid used to drive the motor will also act on reaction surfaces of the pilot drilling unit to urge it axially forward. The top of the pilot drilling unit includes a fishing head for retracting the pilot drilling unit from the drilling tool, and reinserting it therein.

Abstract: Coring samples can be taken in highly fractured rock formations without physical disturbance of the coring sample as it is cut and without jamming the core within the core barrel by using a rotating coring bit characterized by a pilot portion. The pilot portion extends the inner gage to form a longitudinally extending cylindrical surface. The nose of the pilot portion is characterized by a crowned surface wherein cylindrical polycrystalline diamond (PCD) cutting elements are axially disposed and longitudinally extending from the crowned surface. The width of the crowned surface which forms the nose of the pilot portion, is substantially less than the distance between the inner and outer gages of the coring bit. The pilot portion joins a flank portion of the bit through a cylindrical and longitudinally extending pilot gage.

Abstract: A blade-type rotary drill bit having radially divergent cutting blades arranged in two arrays and equipped with cutting blanks having upset cutting surfaces formed of an abrasive material such as diamond or the like. The blades in one array cut to the center of the bit to provide a conically shaped core volume and the blades of the second array terminate short of the axis of the bit to define a somewhat larger core volume. The bit is equipped with discharge ports and baffles whereby drilling fluid issuing from the discharge ports moves downwardly and then inwardly to the center of the bit. The cutting blanks located on the second array of blades cut in a common set of tracks which are at least partially different from and compliment the tracks cut by the cutting blanks on the blade of the first array.

Abstract: A drill bit including a support member and a plurality of concentrically positioned, hollow, cylindrical cutting members connected to the support member is disclosed. Each of the cutting members includes a beveled edge obliquely extending between the inner and outer surfaces thereof. The beveled edges are aligned so that a tapered cutting surface is defined.

Abstract: The present sampler is adapted to take soil samples from the ground surface, from a borehole sunk by other tools, as well as for drilling shallow boreholes. The sampler is provided with an air-operated percussion mechanism and a soil sample receiving sleeve arranged coaxially thereto. The side surface of the sleeve is provided with an annular ridge having a diameter somewhat larger than the diameter of the percussion mechanism housing. This feature enables a reduction of the forces applied to the sampler to sink it into or withdraw it from the soil.