Abstract: Improved drill collars and their manufacture include the assembly of a body member formed of an appropriate high strength material, and a liner within the body. The body member will provide the majority of the strength and weight required of the drill collar, while the liner will be constructed of a material offering improved resistance to corrosion and stress corrosion cracking. The liner may be formed of a metal alloy, and may be retained within the body member by deforming the liner radially outwardly to establish an interference fit with the interior bore of the body member. A sealant may also be placed with the collar between the liner and the body member to seal any space between the two members.

Abstract: A tool face orientation of a directional drill bit within a borehole is efficiently communicated to the well surface by communicating only changes in the tool face orientation. In the first embodiment after the entire tool face orientation is measured and transmitted uphole, and thereafter changes of the tool face orientation as measured with respect to the center of spatially fixed sectorial ranges are transmitted uphole. The magnitude of the changes relative to the center of a fixed sectorial range, being smaller than the range of the entire tool face orientation, allow the subsequent transmission to be made using words of shorter length. Alternatively, the changes in tool face orientation may be measured with respect to a sliding reference point. The sliding reference point may, for example, be the mean value of the prior ten measurements and any previous mean values.

Abstract: A drill bit is provided which includes cutting elements cooperatively arranged with apertures in the bit to define flow paths for hydraulic flow proximate each cutting element. Cutting elements are preferably arranged in cutting pads which generally surround the apertures, such that hydraulic flow is forced to flow across the entire surface of the cutting pad. The dimensions of the cutting pad may be varied so as to control the hydraulic flow.

Abstract: A direct drive for well drilling tools is established which includes a friction bearing with a trace ring and a bearing ring. The bearing ring has a number of bearing segments distributed around its periphery. These bearing segments are supported so that they can be tilted and shifted axially. Each bearing segment includes a support part mounted in a bore of the bearing ring and a compression spring rod arranged in the bore of the bearing ring to provide tilting and axial shifting of the segment against a spring force.

Abstract: A stabilizer for deep well drilling tools is disclosed which includes a tubular outer casing having a plurality of slit openings distributed around its periphery with a tubular adjusting mandrel supported in the casing for relative axial movement therewith in response to well fluid pressure applied to the well. A separate elongated ribbed body is movably mounted in each slit opening. Each of the ribbed bodies has a rear wedge face facing opposite to the relative motion of the mandrel which cooperates with a separate mating wedge face on the mandrel such that the ribbed body moves radially outwardly in its respective slit opening upon contact between said mating wedges upon axial movement of the mandrel relative to the casing in response to well fluid pressure applied to the well. Also, each end of each ribbed body has an axially projecting guide projection which terminates in a reduced dimension at its end.

Abstract: A method of controlling the direction of a drill bit (3) at the downhole end of a drill string (2) drilling from a surface comprises providing two steerable stabilizers (4, 5) at the downhole end of the drill string (2) at locations spaced apart in the drilling direction and adjusting the orientation of the stabilizers to create reactive forces from the bore hole (6) to deflect the course of the bit (3) in a desired direction. The stabilizers (4, 5) are suitably arranged eccentrically and circumferentially offset by 180.degree..+-.60.degree.. In normal drilling the drill string (2) is rotated such that stabilizers (4, 5) engage the bore hole (6) to support a downhole motor (1) against tilting. When off course drilling is sensed the stabilizers are rotated to a position and stopped from rotation such that drilling forces generate reaction forces to cause a desired change of direction.

Abstract: A core drilling tool for bore-holes includes a stem for connection to the string and an outer rotating tube for rotating a drill bit mounted thereon. A core tube is mounted in a central passage by a latch means to remove the core tube and/or replace it. The outer tube is rotated by a downhole motor such as a Moineau type motor. The diameter of the central passage through the stator is equal to the maximum diameter of the core tube plus the eccentricity of the stator to permit passage of the core tube into and out of the tool. Thus coring can be achieved without tripping the tool. Various details of the structure are described.

Abstract: Multistate mud pulsing is achieved by generating both positive and negative pulses within a drill string by means of a plurality of selectively operable bypass passages around a restriction to primary mud flow within a drill string or by venting to outside of the drill string. A fraction of the hydraulic mud is drawn from a location upstream from the restriction into a valve manifold. The removed fraction of hydraulic mud is selectively communicated from the valve manifold either to a point inside a drill string downstream from the restriction or to a point exterior to the drill string in annulus between the outside of the drill string in the borehole. Mud reinjected downstream from the restriction creates a positive pressure pulse within the drill string. Mud which is diverted to the annulus outside of the drill string creates a negative mud pulse within the drill string.

Abstract: A method for manufacturing a reusable package for printed circuits boards in oil tools which is protected from high vibration and high temperature environments is comprised of the steps of vacuum forming a thin layer of mold release film over the printed circuit board. The printed circuit board together with its intimately formed mold release film is then potted in a conventional manner within a protective package filled with a resilient curable foam. The foam is poured in an uncured state around the components of the printed circuit board and cured in place. After the potting material is cured the printed circuit board is removed from the resilient potting material and the mold release layer is stripped from the printed circuit board.

Abstract: The cyclic angular dependence of the output of gravitational inclinometers and magnetometers is used to communicate from the well surface to a microprocessor downhole. The microprocessor controls an arbitrary downhole function. Information is communicated to the microprocessor via the inclinometer and magnetometer by selectively rotating the drill string during a data time interval through a predetermined magnitude of angular displacement or angular velocity. Each additional multiple of angular displacement or angular velocity is interpreted as a distinguishable unit of information. A command word is assembled from a sequential plurality of units of information in the microprocessor and a downhole function is executed according to the command word.

Abstract: Hydraulic flow may be rendered substantially uniform throughout the waterways on a rotating bit from the center of the bit to the outer gage. This is accomplished by defining waterways into the bit face below a primary surface of the bit face. A colinear land is then disposed into the waterway, but does not extend above the primary surface of the bit face. A plurality of teeth are then disposed on the colinear land and extend above the primary surface of the bit face. The flow of hydraulic fluid is prevented from dispersing as the fluid moves from the center of the bit to the outer gage. Cutting by kerfing is further optimized by arranging triads of cutters on each of the pads disposed in the waterways into a set. Each triad of cutters corresponds to additional triads of cutters in azimuthally subsequent and adjacent pads in the next subsequent waterway, thereby forming the set of associated triads of cutters. Each triad of cutters in the set is radially offset from the corresponding triads in the set.

Abstract: Apparatus for and a method of creating positive pressure pulses in a stream of drilling mud being circulated through a drill string is disclosed. The apparatus includes a restriction in the drill string, a valve member located below the restriction, a cylinder located in the drill string above the restriction, a valve stem connected to the valve member and extending upwardly through the restriction into the cylinder, a piston located in the cylinder and connected to the valve stem, and a restricted passage through the piston through which drilling mud can flow and equalize the pressure across the piston. In operation, opening a pilot valve allows the fluid above the piston to flow through the piston rod to the drill string below the restriction. This creates a pressure differential across the piston that moves it upwardly and causing the valve member to further restrict flow through the valve seat. This creates a pressure pulse.

Abstract: A device for selective straight or directional drilling in subterranean rock formations consists of a rotary drilling tool having a tool main axis and comprising a housing which comprises several sections and can be connected to a drill string, the housing having a down-hole motor for driving a drill bit by means of a driven shaft. For straight drilling, the housing can be set in independent, slow rotation about the tool main axis by being turned by the drill string, and for directional drilling can be aligned and fixed against turning. The lower section of the housing adjacent to the drill bit and mounting the driven shaft is deflected relative to the tool main axis, and this section is connected to an upper section by an intermediate section which has an axis which intersects the axes of the upper and lower section, the device may include a plurality of interchangeable intermediate sections.

Abstract: A stabilizer for use in controlled directional drilling includes a plurality of spaced and axially extending blade elements each having a blade surface face of hardened material. The blade surface face includes a tapered lead portion and a tapered trailing portion with a flat non-tapered surface face portion therebetween. Each blade surface includes an edge portion in which the leading edge is radiused. Thus constructed, the stabilizer reduces kerfing into the formation and hang-up and change of tool face orientation during navigational drilling. Eccentric stabilizers are also described.

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: Jamming caused by absorbent members in sponge core barrels or loss of coring information caused by oil wipes in oil field boreholes in which sponge core coring tools are disposed can be avoided by employing a method and tool wherein the absorbent member is formed in placed in contact about the core after the has been cut and disposed within the inner tube. In the illustrated embodiment, a liquid foam is catalytically formed from two constituent parts. The constituent parts are hydraulically forced from longitudinal chambers defined within the inner tube walls into an area in the throat of the bit where the parts meet and exothermically generate a liquid foam. The liquid foam rises into a plurality of longitudinal open chambers defined within the inner tube. Each of the open chambers has a longitudinal slot defined therethrough which communicates the chamber with the axial bore in which the core is disposed.

Abstract: Multistate mud pulsing is achieved by generating both positive and negative pulses within a drill string by means of a plurality of selectively operable bypass passages around a restriction to primary mud flow within a drill string or by venting to outside of the drill string. A fraction of the hydraulic mud is drawn from a location upstream from the restriction into a valve manifold. The removed fraction of hydraulic mud is selectively communicated from the valve manifold either to a point inside a drill string downstream from the restriction or to a point exterior to the drill string in annulus between the outside of the drill string in the borehole. Mud reinjected downstream from the restriction creates a positive pressure pulse within the drill string. Mud which is diverted to the annulus outside of the drill string creates a negative mud pulse within the drill string.

Abstract: In a device for the transmission of information from a borehole to the surface during the operation of a drilling device which comprises a rotary drill bit, a tubular housing and a pump which delivers a drilling fluid downwards through the tubular housing, through the rotary drill bit and upwards in the annular space between the tubular housing and the borehole, there is provided a detector arranged in the tubular housing, for detecting information, a processor for converting that information into a sequence of electrical control signals and a transducer for generating pressure pulses in the downwardly-directed flow of drilling fluid as a function of the control signals, and a remote detector arranged at a position spaced from the processor by a wire-less transmission path with a transmitter unit associated with the remote detector at one end of said path and a receiver unit at the other end of said path.

Abstract: A diamond cutting tooth for use in a petroleum drag bit is provided with an extended and expanded effective diamond cutting surface by providing a linear sequence of triangular prismatic, synthetic, polycrystalline, diamond cutting elements generally along the line of direction of cutting within each tooth. Each element is offset from the preceding element in the sequence in a direction nonparallel to the line of cutting. More particularly, equilateral triangular prismatic diamond elements are laid within a V-shaped groove within a mold from which the cutting tooth is molded through conventional infiltration matrix techniques. The apical opening of the groove is 70 degrees, whereas the apical extent of each of the triangular apexes is 60 degrees. Each triangular element is laid on one side or other of the longitudinal groove.

Abstract: A jarring device for use in drilling comprises first and second members longitudinally relatively movable between a locked position and a released position said device comprising control means including a pair of locking devices each arranged to prevent relative movement between said members until a predetermined force is applied to one of said movable members in either of two longitudinal directions. The control means includes two locking devices each of which locks in one of the two directions.The locking devices may comprise pivotable bolts pivoted on a sliding member so that the free ends of the bolts contact an abutment on one of the movable members to effect locking, the bolts being retracted from engagement with the abutment by movement of the sliding member.