Abstract: An acoustic receiver for use on a drill string includes a housing attachable to the drill string; a first sensor mounted within the housing for measuring a first parameter at a first location on the drill string and for generating a first parameter signal representative of the first parameter; a second sensor mounted within the housing for measuring a second parameter at a second location on the drill string and for generating a second parameter signal representative of the second parameter; and a controller mounted within the housing and communicatively coupled to the first and second sensors. The magnitudes of the first and second parameters vary in proportion to magnitude of the acoustic wave and the first and second parameters have a quadrature phase relationship. The controller is configured to combine the first and second parameter signals to determine the magnitude of the acoustic wave.

Abstract: An acoustic receiver for use on a drill string includes a housing attachable to the drill string; a first sensor mounted within the housing for measuring a first parameter at a first location on the drill string and for generating a first parameter signal representative of the first parameter; a second sensor mounted within the housing for measuring a second parameter at a second location on the drill string and for generating a second parameter signal representative of the second parameter; and a controller mounted within the housing and communicatively coupled to the first and second sensors. The magnitudes of the first and second parameters vary in proportion to magnitude of the acoustic wave and the first and second parameters have a quadrature phase relationship. The controller is configured to combine the first and second parameter signals to determine the magnitude of the acoustic wave.

Abstract: A method for detecting a downhole position in a wellbore comprises: providing a set of signal emitters, each signal emitter in the set attached to a different position in the wellbore and each signal emitter configured to emit a signal having a unique characteristic; and providing a measurement tool comprising a signal detector configured to detect the different signals and a rotation device configured to rotatably contact a wall of the wellbore. The measurement tool is moved through the wellbore and one or more positions of the measurement tool in the wellbore is determined by detecting one or more of the signals and identifying the position of one or more of the signal emitters by the unique characteristic of each detected signal, and by detecting the number of rotations in a ranging wheel of the rotation detector that contacts the wellbore.

Abstract: This invention applies to the means whereby capacitance changes due to varying temperature and/or pressure in a piezoelectric transducer used for acoustic telemetry in a drilling environment is dynamically offset by modifying one or more parameters associated with the drive or control circuitry of said transducer. The object of the invention is to closely maintain the transducer in a resonant mode, thereby ensuring optimum energy consumption.

Abstract: A method for enhancing downhole telemetry performance comprising enhancing a signal in order to offset signal-to-noise ratio reduction with increasing measured depth, wherein the signal is modified at specified measured depths which are inferred from acoustic wave velocity determination.

Abstract: A method whereby a downhole drilling transmission device that communicates to the surface automatically modifies its transmission parameters in order that it substantially improves its ability to adequately communicate with a surface receiver despite increasing signal attenuation between the two as the length of drillpipe increases. This utilizes a simple measure of localized downhole pressure that then relies upon a look-up table or similar that provides a correspondence between said pressure and measured depth. Such a look-up table or similar can be readily built by incorporating appropriate features of the planned well such as drilling fluid flow rate, drilling fluid density, drilling fluid viscosity, well profile, bottom hole assembly component geometry, drillpipe geometry, and indications as to whether the fluid is flowing or stationary.

Abstract: Non-contacting means of measuring the material velocities of harmonic acoustic telemetry waves travelling along the wall of drillpipe, production tubing or coiled tubing are disclosed. Also disclosed are contacting means, enabling measurement of accelerations or material velocities associated with acoustic telemetry waves travelling along the wall of the tubing, utilizing as a detector either a wireless accelerometer system or an optical means, or both; these may also be applied to mud pulse telemetry, wherein the telemetry waves are carried via the drilling fluid, causing strain in the pipe wall that in turn causes wall deformation that can be directly or indirectly assessed by optical means. The present invention enables detection of telemetry wave detection in space-constrained situations. The invention also teaches a substantially contactless method of determining the time-based changes of the propagating telemetry waves.

Abstract: A system and method of closed loop control whereby acoustic telemetry devices, both at surface and downhole, form nodes of a feedback loop; said feedback loop enables an automatic and dynamic means to modify transmission parameters such that the system's telemetry data rate is maximized consistent with minimum achievable signal-to-noise ratio and minimum expended power.

Abstract: An acoustic isolator for use with tubular assemblies such as drillpipe or production tubing comprising an acoustic wave transmitter, the acoustic isolator comprising, in series, an odd integer ?/4 multiple tuning bar of first acoustic impedance adjacent the acoustic wave transmitter, an odd integer ?/4 multiple reflector tube of second acoustic impedance, and a snubber of third acoustic impedance, wherein there is an acoustic impedance mismatch between the odd integer ?/4 multiple tuning bar and the odd integer ?/4 multiple reflector tube and an acoustic impedance mismatch between the odd integer ?/4 multiple reflector tube and snubber, such that a “down” wave propagated toward the isolator is reflected back substantially in phase with an “up” wave propagated from the acoustic wave source away from the isolator.

Abstract: A direct current electric motor brush and brush housing arrangement, comprising means to significantly reduce the effect of brush lift in a brushed motor containing viscous fluid. The means enable viscous fluid to avoid momentum transfer into the brushes by providing two or more pressure relief channels that provide the fluid with direct means of radial exit along the direction of the brush, potentially reducing the brush lift due to the fluid being forced between a rotating commutator and its associated brushes. The pressure relief channels may be located in the housing immediately adjacent to the brush, being radially disposed to the leading face (or leading and trailing faces) of each brush, or in the leading face (or leading and trailing faces) of each brush itself, and may comprise additional channels in the housing near but not immediately adjacent the brushes.

Abstract: A compact, robust, wear resistant, and high performance electrically insulating gap sub for use with borehole EM Telemetry is disclosed. In one embodiment, the gap sub may include an externally threaded mandrel separated from an internally threaded housing by a dielectric material. Additionally, some embodiments may include an external gap ring for separating the upper and lower electrical halves of the sub which offers structural support, acts as the primary external seal, and provides an abrasion resistant non-conductive length on the exterior. Some embodiments may include torsion pins to prevent the possible unscrewing of the dielectric filled threaded sections should the dielectric material become damaged or weakened.

Abstract: An electronic switching circuit system designed to be compatible with coaxial barrel style plug and socket connectors. Specific plug and socket contacts utilize a simple electronic device that causes the switching circuit associated with either or both the plug and socket to be activated only when the plug and socket pair is fully engaged.