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: An invention is claimed wherein the signal loss along steel drill pipe walls can be estimated in the absence of a loss mechanism due to the formation debris at various positions in the well bore; the signal loss in excess of the calculated attenuation is generally and directly attributable to the build-up of said formation debris and an estimation of the amount can be determined. Furthermore, by use of distributed acoustic nodes positioned in the well between the transmitter in the BHA and the surface receiver—configured as repeaters—the formation debris build-up can be determined in each section so defined. This new information enables the driller to implement hole cleaning means in a timely manner and as appropriate, thus avoiding the problems of getting stuck in the hole, and possible well abandonment. An extension of the method enables the hole cleaning process to be automated, thereby improving efficiency.

Abstract: A gap sub assembly can be used to form an electrical isolation in a drill string, across which a voltage is applied to generate a carrier signal for an electromagnetic (EM) telemetry system. The assembly comprises two conductive generally cylindrical components fashioned with a matching set of male and female rounded coarse threads, held such that a relatively uniform interstitial space is formed in the overlap space between them. The third component is a substantially dielectric electrical isolator component placed into the gap between the threads that effectively electrically isolates the two conductive components. Injecting the dielectric material under high pressure forms a tight bond resistant to the ingress of conductive drilling fluids (liquids, gases or foam), thus forming a high pressure insulating seal.

Abstract: A gap sub assembly can be used to form an electrical isolation in a drill string, across which a voltage is applied to generate a carrier signal for an electromagnetic (EM) telemetry system. The assembly comprises two conductive generally cylindrical components fashioned with a matching set of male and female rounded coarse threads, held such that a relatively uniform interstitial space is formed in the overlap space between them. The third component is a substantially dielectric electrical isolator component placed into the gap between the threads that effectively electrically isolates the two conductive components. Injecting the dielectric material under high pressure forms a tight bond resistant to the ingress of conductive drilling fluids (liquids, gases or foam), thus forming a high pressure insulating seal.

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 direct current electric motor brush and brush housing arrangement which significantly reduces the effect of brush lift in a brushed motor containing viscous fluid. The brush housing enables viscous fluid to avoid momentum transfer into the brushes by providing two or more pressure relief channels that provide the fluid with direct radial exits 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 include additional channels in the housing near but not immediately adjacent the brushes.

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 stacked-ring, slow-wave acoustic telemetry isolation system and method for use with tubular assemblies such as drillpipe or production tubing comprising an acoustic wave transmitter, the acoustic isolator behaving 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. The acoustic isolator is similarly effective in reflecting “up” propagating waves originating from below the isolator, hence further protecting the acoustic wave source from possible deleterious interference. It causes substantially all of the emitted wave energy to travel in a chosen direction along the drill pipe, thus aiding the efficiency of acoustic telemetry said pipe.

Abstract: A system and method of closed loop control whereby groupings of surface sonic transmitters disposed along the planned path of a well send sonic wave energy to a downhole sonic receiver (or alternatively a downhole sonic transmitter signalling to grouping of surface sonic receivers) in a manner that facilitates the downhole positioning of the well. Subsequent offset well positioning, relative to the first well, may be achieved in a similar manner.

Abstract: An acoustic telemetry isolation system and method for use with tubular assemblies such as drillpipe and production tubing includes an acoustic wave transmitter and an acoustic isolator. 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. Furthermore, the acoustic isolator is similarly effective in reflecting “up” propagating waves originating from below the isolator, hence further protecting the acoustic wave source from possible deleterious interference. The construction of the isolator utilizes a specified combination of waves traveling in parallel in materials whose properties aid the beneficial combination of reflected and transmitted waves. The design of the isolator is to generally provide a bandstop filter function, thereby aiding the frequency isolation of an acoustic transmitter over a passband that may be constrained by the geometry of drill pipe or components of production tubing.

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: 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 connection, 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 gap sub assembly can be used to form an electrical isolation in a drill string, across which a voltage is applied to generate a carrier signal for an electromagnetic (EM) telemetry system. The assembly comprises two conductive generally cylindrical components fashioned with a matching set of male and female rounded coarse threads, held such that a relatively uniform interstitial space is formed in the overlap space between them. The third component is a substantially dielectric electrical isolator component placed into the gap between the threads that effectively electrically isolates the two conductive components. Injecting the dielectric material under high pressure forms a tight bond resistant to the ingress of conductive drilling fluids (liquids, gases or foam), thus forming a high pressure insulating seal.

Abstract: A spindle for a mud pulse telemetry tool includes a seal section having an outer surface for contacting a lip seal of a spindle housing in which the spindle is mounted; a top section attachable to at least part of a valve assembly for generating mud pulses; and a base section having a proximal end attachable to a drive motor for moving the spindle and a distal end attachable to the top section such that the annular seal is fixed between the top and base sections. The seal section can be made of a ceramic material such as yttrium-stabilized zirconia.

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.

Abstract: A method is provided which transmits information using a plurality of data transmission nodes situated along a drill string. In this method, a first node obtains a transmission status of a second node. When the transmission status of the second node indicates that the second node meets a selected performance threshold, information is sent from the first node to the second node. When the transmission status of the second node indicates that the second node does not meet its performance threshold, then the first node obtains a transmission status of a third node. When the transmission status of the third node indicates that the third node meets a selected performance threshold, information is transmitted from the first node to the third node for relaying along the drill string.

Abstract: A gap sub assembly can be used to form an electrical isolation in a drill string, across which a voltage is applied to generate a carrier signal for an electromagnetic (EM) telemetry system. The assembly comprises two conductive generally cylindrical components fashioned with a matching set of male and female rounded coarse threads, held such that a relatively uniform interstitial space is formed in the overlap space between them. The third component is a substantially dielectric electrical isolator component placed into the gap between the threads that effectively electrically isolates the two conductive components. Injecting the dielectric material under high pressure forms a tight bond resistant to the ingress of conductive drilling fluids (liquids, gases or foam), thus forming a high pressure insulating seal.

Abstract: The invention relates to an apparatus for receiving downhole acoustic signals, processing the signals into electric signals, then transmitting the signals wirelessly to a remote above-surface monitoring station. The apparatus is mountable to an above-surface rotatable component used in borehole application. The apparatus includes an instrument housing, and a clamping assembly attached to the housing and having sufficient length and flexibility to enable the apparatus to surround the perimeter of the rotatable component.

Abstract: A dual transformer design, each transformer having at least a primary winding and a secondary winding disposed on a core means, wherein the core means is circumferentially disposed about an inner housing means, and the whole structure located within an outer housing. The primary winding of one transformer of said pair of transformers is electrically coupled to the primary winding of the other in a manner such as to cause induced eddy currents from one transformer to be of a magnitude and direction so as to substantially cancel the induced eddy currents from the other transformer.