Abstract: A method for operating an impulsive type seismic energy source in a firing sequence having at least two actuations for each seismic impulse to be generated by the source. The actuations have a time delay between them related to a selected energy frequency peak of the source output. One example of the method is used for generating seismic signals in a wellbore and includes discharging electric current through a spark gap disposed in the wellbore in at least one firing sequence. The sequence includes at least two actuations of the spark gap separated by an amount of time selected to cause acoustic energy resulting from the actuations to have peak amplitude at a selected frequency.

Abstract: A wellbore seismic source includes a sparker electrically coupled to a power source. The sparker is disposed in a pressure-sealed canister, wherein the canister is at least partially filled with liquid. At least one of the pressure of the liquid and the energy discharged by the power source through the sparker is selected to cause emission of acoustic energy at a selected frequency.

Abstract: A wellbore seismic source includes a sparker electrically coupled to a power source. The sparker is disposed in a pressure-sealed canister, wherein the canister is at least partially filled with liquid. At least one of the pressure of the liquid and the energy discharged by the power source through the sparker is selected to cause emission of acoustic energy at a selected frequency.

Abstract: A method for operating an impulsive type seismic energy source in a firing sequence having at least two actuations for each seismic impulse to be generated by the source. The actuations have a time delay between them related to a selected energy frequency peak of the source output. One example of the method is used for generating seismic signals in a wellbore and includes discharging electric current through a spark gap disposed in the wellbore in at least one firing sequence. The sequence includes at least two actuations of the spark gap separated by an amount of time selected to cause acoustic energy resulting from the actuations to have peak amplitude at a selected frequency.

Abstract: A cutting element and a method for forming a cutting element is described and shown. The cutting element includes a substrate, a TSP diamond layer, a metal interlayer between the substrate and the diamond layer, and a braze joint securing the diamond layer to the substrate. The thickness of the metal interlayer is determined according to a formula. The formula takes into account the thickness and modulus of elasticity of the metal interlayer and the thickness of the TSP diamond. This prevents the use of a too thin or too thick metal interlayer. A metal interlayer that is too thin is not capable of absorbing enough energy to prevent the TSP diamond from fracturing. A metal interlayer that is too thick may allow the TSP diamond to fracture by reason of bending stress. A coating may be provided between the TSP diamond layer and the metal interlayer. This coating serves as a thermal barrier and to control residual thermal stress.

Abstract: A superabrasive fracture resistant compact is formed by depositing successive layers of ceramic throughout the network of open pores in a thermally stable self-bonded polycrystalline diamond or cubic boron nitride preform. The void volume in the preform is from approximately 2 to 10 percent of the volume of the preform, and the average pore size is below approximately 3000 nanometers. The preform is evacuated and infiltrated under at least about 1500 pounds per square inch pressure with a liquid pre-ceramic polymerizable precursor. The precursor is infiltrated into the preform at or below the boiling point of the precursor. The precursor is polymerized into a solid phase material. The excess is removed from the outside of the preform, and the polymer is pyrolized to form a ceramic. The process is repeated at least once more so as to achieve upwards of 90 percent filling of the original void volume.

Abstract: A method enabling controlled selective heating of workpiece components during microwave brazing. Two workpiece components are joined by melting an adhesion interlayer material between the two components. An indication of when the interlayer has melted is provided. The temperature difference across the braze assembly is monitored and adjusted via a feedback loop to reduce stresses in the braze joint resulting in a stronger braze joint.

Abstract: A method is disclosed for the manufacture of a drill bit having a hollow tubular body, or drill bit components, with an exterior tungsten carbide coated surface, and with cutting elements positioned in the cutting surfaces thereof. The drill bit body, or a bit component, such as a cutting blade, is formed by casting in a mold providing the precise dimensions required in the finished bit. The mold is packed or coated over selected portions of the inner surface with particles of sintered tungsten carbide or similar sintered refractory hard metal. The mold has a plurality of soft iron or steel plugs extending from the walls thereof which are of the same diameter as the cutting inserts or passages into the bit body or bit component. A steel alloy, or cast iron, or nodular cast iron, is melted and poured into the mold. The temperature of the molten steel is sufficient to desinter the sintered tungsten carbide particles.

Abstract: A drag blade bit for connection on a drill string has a hollow body on which there are welded a plurality of cutting or drilling blades. The blades extend longitudinally and radially of the bit body and terminate in relatively flat, radially extending cutting edges. A plurality of cutters are positioned in and spaced along the cutting edges and consists of cylindrical sintered carbide inserts with polycrystalline diamond cutting elements mounted thereon. Hardfacing is provided on the cutting edges between the cutters and on the other surfaces of the blades and the bit body subject to abrasive wear. One or more nozzles are positioned in passages from the interior of the bit body for directing flow of drilling fluid for flushing cuttings from the well bore and for cooling the bit.

Abstract: A drill bit for connection on a drill string has a hollow tubular body with an end cutting face and an exterior peripheral stabilizer surface with cylindrical sintered carbide inserts positioned therein. Nozzle passages extend from the interior of the bit body through the cutting face for receiving a removable and interchangeable nozzle member therein. The nozzle has a fluted or non-circular cross-section with grooved portions or out of round portions providing sufficient clearance for drilling fluid to continue to flow through the nozzle even when the main passage thereof is blocked with mud particles or the like. The cutting face has a plurality of recesses therein which receive, by an interference fit, a plurality of cutting elements of the type known as Stratapax, consisting of a cylindrical stud having an angular supporting surface with a cutting disc bonded thereon consisting of sintered carbide having a cutting surface of polycrystalline diamond.

Abstract: A drill bit for connection on a drill string has a hollow tubular body with an end cutting face and an exterior peripheral stabilizer surface with cylindrical sintered carbide inserts positioned therein having polycrystalline diamond cutting elements mounted on said inserts. Said inserts each having a longitudinal recess therein filled with a soft, heat conducting metal operable to facilitate the transfer of heat away from said cutting elements. The drill bit is also provided with removable and replacable nozzles.

Abstract: A drill bit for connection on a drill string has a hollow tubular body with an end cutting face and an exterior peripheral stabilizer surface with cylindrical sintered carbide inserts positioned therein. Nozzle passages extend from the interior of the bit body through the cutting face for receiving a removable and interchangeable nozzle member therein. The cutting face has a plurality of recesses therein which receive, by an interference fit, a plurality of cutting elements of the type known as STRATAPAX, consisting of a cylindrical stud having an angular supporting surface with a cutting disc bonded thereon consisting of sintered carbide having a cutting surface of polycrystalline diamond. The recesses in the cutting face have milled offset recesses adjacent to the edges thereof which are sized and positioned to permit the cutting discs to be partially recessed and to restrain the cutting elements from rotation during use.

Abstract: A drill bit for connection on a drill string has a hollow tubular body with an end cutting face provided with a tungsten carbide coated surface and an exterior peripheral stabilizer surface with cylindrical sintered carbide inserts positioned therein. Nozzle passages extend from the interior of the bit body through the cutting face for receiving a removable and interchangeable nozzle member therein. The cutting face has a plurality of recesses therein which receive, by an interference fit, a plurality of cutting elements of the type known as STRATAPAX, consisting of a cylindrical stud having an angular supporting surface with a cutting disc bonded thereon consisting of sintered carbide having a cutting surface of polycrystalline diamond. The recesses in the cutting face have milled offset recesses adjacent to the edges thereof which are sized and positioned to permit the cutting discs to be partially recessed and to restrain the cutting elements from rotation during use.

Abstract: A drill bit for connection on a drill string has a hollow tubular body with an end cutting face and an exterior peripheral stabilizer surface with cylindrical sintered carbide inserts positioned therein and a novel arrangement for securing replaceable nozzles. Nozzle passages extend from the interior of the bit body through the cutting face for receiving a removable and interchangeable nozzle member therein. A portion of the length of each passage is threaded and the remainder of the passage is enlarged and of a smooth bore. The nozzle member is formed of wear-resistant hard metal, e.g. carbide, and has a metal sleeve brazed thereon with male threads operable to be fitted in the threads in said nozzle passage. The nozzle member is threadedly secured in place during installation and optionally further secured against unscrewing and additionally protected against wear or erosion by a metal or hard metal, e.g. carbide, retaining ring having an interference fit in the smooth portion of the nozzle passage.

Abstract: A drag drill bit includes a plurality of cutter assemblies comprising synthetic polycrystalline diamonds which are held by brazing material within dimensionally controlled pockets formed in the drill bit matrix. The method of manufacturing the bit includes forming the drill bit head by powder metallurgy with a plurality of dimensionally controlled pockets, placing brazing material in communication with each pocket, locating and fixturing a cutter assembly within each pocket by force-fit and brazing the cutter assemblies to the bit head by a furnace cycle.