Abstract: A fallback prevention valve apparatus, system and method is described. An electric submersible pump (ESP) fallback prevention system includes an ESP assembly positioned in a downhole well, the ESP assembly including production tubing extending between a centrifugal pump and a surface of the downhole well such that during operation of the ESP assembly production fluid flows upward from the centrifugal pump through the production tubing to the surface, the production tubing including a fallback valve actuatable by the flow of production fluid, the fallback valve actuatable between an open position, wherein production fluid flowing upward through the fallback valve actuates the fallback valve into the open position, and a closed position, wherein production fluid flowing downward through the fallback valve actuates the fallback valve into the closed position, the closed position blocking sand carried by the production fluid from falling into the centrifugal pump.

Abstract: A downhole connection includes a rotating member and an independently rotating member. A solenoid is connected to the independently rotating member and a moving member is connected to the rotating member. The moving member is movable by the solenoid and connected to an actuation valve of a downhole tool on the rotating member.

Abstract: Methods and systems for generating pulses in drilling fluid are described. The methods include driving rotation of a rotor relative to a stator of a pulser assembly in an oscillatory manner. The oscillatory manner includes rotating an obstructing element from a middle position to a first blocking angle position and rotating the obstructing element from the first blocking angle position to a second blocking angle position such that selective obstruction occurs. Rotation of the at least one obstructing element selectively obstructs a stator flow passage when drilling fluid is flowing through the drill string to generate a pressure pulse in the drilling fluid and the oscillatory manner is an oscillation of the obstructing element between the first blocking angle position and the second blocking angle position such that a single oscillation is between two obstructed states of the stator flow passage.

Abstract: A system for fluidic siren based telemetry is provided. The system includes a non-rotating restrictor and a rotating restrictor positioned relative to the non-rotating restrictor that is configured to control a flow passage to the non-rotating restrictor. The system includes a turbine coupled to the rotating restrictor and configured to rotate in response to fluid flow along a flow path. The system also includes a generator coupled to the turbine and a controller device electrically coupled to the generator. The controller device is configured to provide one or more encoded signals to the generator to adjust a rotational velocity of the rotating restrictor and causing the rotating restrictor to create different acoustic signatures through the flow passage for wireless communication of a telemetry signal to a surface based on the adjusted rotational velocity of the rotating restrictor.

Abstract: An apparatus for generating pressure variances in a flowing fluid includes a first member having a body and a second member. The second member is displaceable about a rotational axis to at least partially block fluid flow through one or more channels in the first member and at least partially reduce the blockage of this fluid flow. The second member has a hub and at least one section extending axially and radially from the hub relative to the rotational axis of the second member. A related method includes guiding fluid across the first member using the channel(s); selectively blocking the fluid flow through the channel(s) using at least one section of a second member; and moving the second member using an actuator to reduce the blockage of the flow of fluid through the channel(s).

Abstract: A downhole rotating machine includes a stator having stator windings and corresponding magnetic flux guides and a rotor having a plurality of magnets configured to cooperate with the stator windings and the corresponding magnetic flux guides to generate a magnetic field in a magnetic gap that is substantially parallel to an axis of rotation of the rotor, wherein the magnetic gap provides a magnetic gap separation between the plurality of magnets and the corresponding magnetic flux guides that is at least five percent of an overall diameter of the downhole rotating machine. A method of operating a downhole tool in a wellbore and a downhole tool are also provided.

Abstract: A drilling tool includes a tubular housing, a bit drive shaft configured to rotate in the housing and support a rotary drill bit at a lower end of the bit drive shaft, and a plurality of bracing devices arranged in the housing. The drilling tool also includes a control device configured to actuate the bracing devices, wherein the bracing devices include anchoring elements and an actuator assembly to which the anchoring elements are coupled The anchoring elements are distributed over the circumference of the housing, wherein the anchoring elements are movable radially outwardly and inwardly and are configured to be retracted into grooves in the housing The radial movability of said anchoring elements is temperature-controlled by the actuator assembly which includes at least one heat-expandable pressure medium, and wherein the pressure medium includes at least one of a gas and a liquid.

Abstract: A measurement while drilling (MWD) tool includes a sensor, an encoder operably connected to the sensor and a modulator operably connected to the encoder. The modulator includes a first stator, a rotor and a second stator. The rotor is optimally positioned between the first and second stator. The use of a second stator amplifies the pressure pulse signal produced by the modulator.

Abstract: According to one embodiment, a mud pulse telemetry tool includes a body having a channel, a motor, and a valve coupled to the motor and disposed within the channel. The valve includes a plurality of lobes, with at least one of the plurality of lobes having a cavity formed therein.

Abstract: An apparatus for use in a wellbore is disclosed that in one non-limiting embodiment includes a flow restriction device that that contains a channeling element having a fluid flow passage, a restriction element spaced from the channeling element defining a gap between the restriction element and the channeling element, wherein relative movement between the restriction element and the channeling element obstructs flow of a fluid flowing through the flow passage to increase pressure in the fluid across the device. In one embodiment an activation device displaces one of the channeling element and the restriction element to adjusts or alter gap in response to certain changes in the pressure across the restriction device.

Abstract: A measurement while drilling (MWD) tool includes a sensor, an encoder operably connected to the sensor and a modulator operably connected to the encoder. The modulator includes a first stator, a rotor and a second stator. The rotor is optimally positioned between the first and second stator. The use of a second stator amplifies the pressure pulse signal produced by the modulator.

Abstract: The embodiments described herein generally relate to a fluid pressure pulse generating apparatus with a primary seal assembly, back up seal assembly and pressure compensation device. The pressure compensation device comprises a membrane support and a longitudinally extending membrane system. The membrane support has a longitudinally extending bore therethrough for receiving a driveshaft of the fluid pressure pulse generating apparatus. The longitudinally extending membrane system comprising a longitudinally extending outer membrane sleeve and a longitudinally extending inner membrane sleeve with the inner membrane sleeve positioned inside the outer membrane sleeve. The membrane system is sealed to the membrane support to allow flexing of the membrane system in response to fluid pressure on either an inner longitudinal surface of the membrane system or an outer longitudinal surface of the membrane system and to prevent fluid on the inner longitudinal surface mixing with fluid on the outer longitudinal surface.

Abstract: A fluid pressure pulse generator comprising a stator and rotor that can be used in measurement while drilling using mud pulse or pressure pulse telemetry is disclosed. The stator comprises a stator body with a circular opening therethrough and the rotor comprises a circular rotor body rotatably received in the circular opening of the stator body. One of the stator body or the rotor body comprises one or more than one fluid opening for flow of fluid therethrough and the other of the stator body or the rotor body comprises one or more than one full flow chamber. The rotor is rotatable between a full flow configuration whereby the full flow chamber and the fluid opening align so that fluid flows from the full flow chamber through the fluid opening, and a reduced flow configuration whereby the full flow chamber and the fluid opening are not aligned.

Abstract: A fluid pressure pulse generating apparatus including a pulser assembly and a fluid pressure pulse generator and methods of using the fluid pressure pulse generating apparatus. The pulser assembly comprises a motor, a sensor for detecting rotation of the motor, a driveshaft rotationally coupled to the motor, and processing and motor control equipment communicative with the motor and the sensor. The fluid pressure pulse generator is coupled with the driveshaft. The sensor provides an indication of the amount of rotation of the motor and this information can be processed by the processing and motor control equipment to determine the position of the driveshaft and to control rotation of the driveshaft based on a predetermined rotational relationship between the driveshaft and the motor.

Abstract: A real time telemetry system is disclosed for use with a drilling system including a rotary valve 28 controlling the supply of drilling fluid or mud to a downhole tool. The system comprises receiving data to be transmitted, encoding the data as a duration, and controlling the rotation the rotary valve 28 such that the rotary valve 28 is rotated for the said duration at a predetermined rotary speed to cause the formation of pressure fluctuations or waves in the drilling fluid or mud.

Abstract: An apparatus, method, and system described for generating pressure pulses in a drilling fluid utilizing a flow throttling device longitudinally and axially positioned within the center of a main valve actuator assembly is described. The main valve actuator assembly includes a main valve pressure chamber, a magnetic cup encompassing a rotary magnetic coupling, and a pilot actuator assembly.

Abstract: An apparatus and method of performing a wellbore operation. The apparatus includes a drill bit that has a cavity at an end thereof and a communication device placed in the cavity. The communication device includes a first section and a second section. An outer dimension of the second section is greater than an outer dimension of the first section. The second section includes a conduit configured to allow passage of a conductor from the drill bit to a location outside the drill bit so as to provide a direct connection of the conductor from the drill bit to an element outside the drill bit.

Abstract: A method of modulating information on pressure fluctuations transmitted via a tubular string can include applying pressure to a piston, thereby axially displacing the piston, axially displacing and rotating an intermediate sleeve in response to the piston displacement, rotating an output member in response to the axial displacement and rotation of the intermediate sleeve, and rotating a variable flow restrictor rotor relative to a stator, the rotor being connected to the output member. A mud pulser can include a variable flow restrictor, and an actuator which operates the flow restrictor and modulates information on pressure fluctuations produced by the flow restrictor, the actuator including a piston which displaces axially in response to a pressure differential, an intermediate sleeve which is both rotated and displaced axially by the piston, and an output member which is rotated by both rotation and axial displacement of the intermediate sleeve.

Abstract: A method for a pressure release encoding system for communicating downhole information through a wellbore to a surface location includes positioning a valve and a brake in a drilling mud circulation system, initiating flow of drilling mud through the system, sensing flow through the valve and setting the brake at predefined pressure levels, sensing downhole conditions and releasing corresponding percentages of pressure across the valve at time intervals, and determining the downhole conditions at the surface by analyzing those associated time intervals. The method includes activation of the encoding system using drilling mud flow and setting predefined pressure levels, so that the pressure drops in the encoding process are from predefined levels at equilibrium and independent of fluid flow.

Abstract: Pressure measurements are made using a pressure sensor in the proximity of the drillbit during drilling operations. A filtered version of the pressure measurements is provided to a pulser for a mud-pulse telemetry system so as to cancel pressure variations due to drilling noise while a telemetry signal is being sent. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: A drillstring combination pressure reducing and signaling valve assembly uses multiple ball valves mounted in parallel, each having a different bore, to meter the flow through a drillstring. The individual ball valves are maintained in either a fully open or a fully closed position, but can be selectively moved between these two positions. The bores of the individual ball valves are sized so that at a given pressure, a first ball valve has a predetermined flow rate, a second ball valve has twice the flow rate of the first ball valve, a third ball valve has twice the flow rate of the second ball valve, and the remaining ball valves each have twice the flow rate of their predecessor in the valve sequence. This arrangement permits the flow rate and flow pressure drop through the assembly of valves to be digitally controlled by varying the combination of open and closed valves.

Abstract: An apparatus for creating pressure pulses in the fluid of a bore hole is described. The preferred embodiment takes the form of a mud pulser apparatus having a signalling valve controlled by a variable pilot valve. The forces on the signalling valve are balanced and controlled by the flow of mud through the variable orifice of the pilot valve. The arrangement is such as to act like a hydraulic amplifier, and results in the signalling valve being compensated for variable flow rates. In the preferred embodiment, the pilot valve has rotary vanes that allow it to be self-cleaning.

Abstract: A rotary pulser for transmitting information to the surface from down hole in a well by generating pressure pulses encoded to contain information. The pulser includes a rotor having blades that are capable of imparting a varying obstruction to the flow of drilling fluid through stator passages, depending on the circumferential orientation of the rotor, so that rotation of the rotor by a motor generates the encoded pressure pulses. A spring biases the rotor toward the stator so as to reduce the axial gap between the rotor and stator. When the pressure drop across the rotor becomes excessive, such as when increasing drilling fluid flow rate or switching from a high data rate to a low data rate transmission mode, the spring bias is overcome so as to increase the axial gap and reduce the pressure drop across the rotor, thereby automatically reducing the thrust load on the bearings.

Abstract: A downhole tool includes a tool body, stator, and rotor. The tool body is aligned along a tool centerline and includes an aperture therethrough operable to pass a fluid to an exterior of the body. The stator is fixed relative to the tool body and includes a fluid flow restriction operable to pass at least a portion of the fluid from an interior of the stator to the exterior of the body at an adjustable flow rate. The rotor is disposed within the tool body and rotatable relative to the stator and includes an exhaust port selectively aligned with at least one aperture through the tool body by rotation of the rotor relative to the stator. The exhaust port is operable to pass at least a portion of the fluid from an interior of the rotor to the exterior of the body when aligned with the aperture.

Abstract: Methods and systems for pulse generation assembly that includes a plurality of staged valves operably coupled serially in a bottomhole assembly of a wellbore tool. The plurality of staged valves are operated in a substantially synchronized manner, thereby generating a series of pressure pulses. The signal strength of the generated pulse signal is multiplied by the number of staged valves in the series, and the pulse generation assembly of the disclosure is less susceptible to jamming, shock, and erosion. Further, by sequentially stopping at least one stage of the assembly and then synchronously rotating other stages, amplitude modulation is accomplished.

Abstract: The present invention is a method and apparatus used to transmit information to the surface from a subsurface location during the process of drilling a bore hole comprising a pressure pulse generator or “pulser” coupled to a sensor package, a controller, an active electromagnetic system for subsurface collision avoidance, and a battery power source all of which reside inside a short section of drill pipe close to the bit at the bottom of the bore hole being drilled wherein the apparatus or “MWD Tool” can be commanded from the surface to make a measurement of desired parameters and transmit this information to the surface by encoding data in pressure pulses generated by a pulser valve that includes a stator and a rotor which may be open and closed to create pressure pulses.

Abstract: A pressure release encoding system for communicating downhole information through a wellbore to a surface location include a downhole tool with a valve for providing a fluid restriction to fluid passing in the wellbore, a sensor positioned in the wellbore for sensing a downhole condition in the wellbore, a brake cooperative with the valve for moving the valve between at least two positions in timed relation to the downhole condition sensed by the sensor, and a detector positioned at the surface location for providing a measurement value at the surface location correlative to the time between the changes of the pressure of the fluid in the wellbore. The system associates position of the valve with pressure transduction. The sensor is an inclination sensor for sensing an angle of inclination of the wellbore.

Abstract: A method and apparatus used to transmit information to the surface from a subsurface location during the process of drilling a bore hole is described. A novel pressure pulse generator or “pulser” is coupled to a sensor package, a controller and a battery power source all of which reside inside a short section of drill pipe close to the bit at the bottom of the bore hole being drilled. The assembled apparatus or “MWD Tool” can be commanded from the surface to make a measurement of desired parameters and transmit this information to the surface by encoding data in pressure pulses generated by a pulser valve that includes a stator and a rotor which may be open and closed to create pressure pulses.

Abstract: An improved energy efficient intelligent pulser driver used for generating a mud pulse in a MWD (measurement while drilling) application. In the pulser driver, a direct current (DC) powered control circuit activates a three-phase DC brushless motor that operates a servo-valve. Opening of the servo-valve equalizes pressure in a plenum causing the operation of a main valve reducing flow area and causing a pressure spike in the mud column. Closing of the servo-valve creates a reduction in mud pressure that operates the main valve and increases the flow area causing an end to the pressure spike. The servo-valve is powered both in opening and closing operations by the motor.

Abstract: A downhole telemetry system for use in a wellbore including borehole fluid. The system includes a stator including flow channels though the stator and a rotor including flow channels though the rotor. The rotor is rotatable on a drive shaft by the force of the borehole fluid flowing through the rotor. The rotation of the rotor creates pressure variations in the borehole fluid related to the movement of the rotor channels relative to the stator channels, thus forming a carrier wave. A regulating system adjusts the amount of fluid force on the rotor for a given flow rate of borehole fluid to maintain the frequency of the carrier wave within a range of a target frequency. Also, an alternator drivable by the rotation of the drive shaft provides power to the system. The system also includes an encoder capable of adjusting the rotation of the rotor to modulate the carrier wave.

Abstract: A pressure release encoding system for communicating downhole information through a wellbore to a surface location include a downhole tool with a valve for providing a fluid restriction to fluid passing in the wellbore, a sensor positioned in the wellbore for sensing a downhole condition in the wellbore, a brake cooperative with the valve for moving the valve between at least two positions in timed relation to the downhole condition sensed by the sensor, and a detector positioned at the surface location for providing a measurement value at the surface location correlative to the time between the changes of the pressure of the fluid in the wellbore. The system associates position of the valve with pressure transduction. The sensor is an inclination sensor for sensing an angle of inclination of the wellbore.

Abstract: A shaft protection washer to protect a rotating shaft in a “measurement while drilling” (MWD) tool. Use of the shaft protection washer renders the rotating shaft less susceptible to erosion from the drilling fluid flowing between the rotating component and the stationary component.

Abstract: An oscillating shear valve system for generating pressure fluctuations in a flowing drilling fluid comprising a stationary stator and an oscillating rotor, both with axial flow passages. The rotor oscillates in close proximity to the stator, at least partially blocking the flow through the stator and generating oscillating pressure pulses. The rotor passes through two zero speed positions during each cycle, facilitating rapid changes in signal phase, frequency, and/or amplitude facilitating enhanced, multivalent data encoding. The rotor is driven by a motorized gear drive. In one embodiment, a torsional spring is attached to the motor and the resulting spring mass system is designed to be near resonance at the desired pulse frequency. The system enables the use of multivalent encoding schemes for increasing data rates.

Abstract: An apparatus for creating pressure pulses in the fluid of a bore hole is described. The preferred embodiment takes the form of a mud pulser apparatus (10) having a signalling valve controlled by a variable pilot valve (34). The forces on the signalling valve are balanced and controlled by the flow of mud through the variable orifice of the pilot valve. The arrangement is such as to act like a hydraulic amplifier, and results in the signalling valve being compensated for variable flow rates. In the preferred embodiment, the pilot valve has rotary vanes that allow it to be self-cleaning.

Abstract: A method and apparatus used to transmit information to the surface from a subsurface location during the process of drilling a bore hole is described. A novel pressure pulse generator or “pulser” is coupled to a sensor package, a controller and a battery power source all of which reside inside a short section of drill pipe close to the bit at the bottom of the bore hole being drilled. The assembled apparatus or “MWD Tool” can be commanded from the surface to make a measurement of desired parameters and transmit this information to the surface by encoding data in pressure pulses generated by a pulser valve that includes a stator and a rotor which may be open and closed to create pressure pulses.

Abstract: An improved energy efficient intelligent rotary pulser for generating a mud pulse in a MWD (measurement while drilling) application. In the rotary pulser, a control circuit activates a brushless motor that rotates a windowed restrictor relative to a fixed housing to act as a shutter and window respectively. Opening of the windowed restrictor allows generally unrestricted mud flow. Closing of the windowed restrictor generally restricts mud flow. The windowed restrictor is powered both in opening and closing operations by the motor.

Abstract: A downhole telemetry system for use in a wellbore including borehole fluid. The system includes a stator including flow channels though the stator and a rotor including flow channels though the rotor. The rotor is rotatable on a drive shaft by the force of the borehole fluid flowing through the rotor. The rotation of the rotor creates pressure variations in the borehole fluid related to the movement of the rotor channels relative to the stator channels, thus forming a carrier wave. A regulating system adjusts the amount of fluid force on the rotor for a given flow rate of borehole fluid to maintain the frequency of the carrier wave within a range of a target frequency. Also, an alternator drivable by the rotation of the drive shaft provides power to the system. The system also includes an encoder capable of adjusting the rotation of the rotor to modulate the carrier wave.

Abstract: An improved energy efficient intelligent pulser driver used for generating a mud pulse in a MWD (measurement while drilling) application. In the pulser driver, a direct current (DC) powered control circuit activates a three-phase DC brushless motor that operates a servo-valve. Opening of the servo-valve equalizes pressure in a plenum causing the operation of a main valve reducing flow area and causing a pressure spike in the mud column. Closing of the servo-valve creates a reduction in mud pressure that operates the main valve and increases the flow area causing an end to the pressure spike. The servo-valve is powered both in opening and closing operations by the motor.

Abstract: A shaft protection washer to protect a rotating shaft in a “measurement while drilling” (MWD) tool. Use of the shaft protection washer renders the rotating shaft less susceptible to erosion from the drilling fluid flowing between the rotating component and the stationary component.

Abstract: A real time telemetry system is disclosed for use with a drilling system including a rotary valve 28 controlling the supply of drilling fluid or mud to a downhole tool. The system comprises receiving data to be transmitted, encoding the data as a duration, and controlling the rotation the rotary valve 28 such that the rotary valve 28 is rotated for the said duration at a predetermined rotary speed to cause the formation of pressure fluctuations or waves in the drilling fluid or mud.

Abstract: An apparatus for mud pulse telemetry for transmitting information from a drill string positioned at a down hole location in a bore hole to a surface location, the drill string having a flow passage through which a drilling fluid flows is provided. In one aspect, the apparatus includes a rotor pulser having an uncompensated drive train comprising a unique uncompensated seal comprising a stacked array of seal elements. The uncompensated drive train provides for the direct coupling of a rotor to a drive motor. The drive motor is located within an internal housing that is filled with gas at atmospheric pressure. Additionally, a method of operating the apparatus is provided. The method includes measuring drilling fluid pressure within the flow passage to determine when a pipe connection is being made to the drill string to initiate the measurement of a down hole parameter. The down hole parameter information is transmitted to the surface through a series of encode pressure pulse generated in the drilling fluid.

Abstract: An improved energy efficient intelligent pulser driver used for generating a mud pulse in a MWD (measurement while drilling) application. In the pulser driver, a direct current (DC) powered control circuit activates a three-phase DC brushless motor that operates a servo-valve. Opening of the servo-valve equalizes pressure in a plenum causing the operation of a main valve reducing flow area and causing a pressure spike in the mud column. Closing of the servo-valve creates a reduction in mud pressure that operates the main valve and increases the flow area causing an end to the pressure spike. The servo-valve is powered both in opening and closing operations by the motor.

Abstract: Apparatuses and methods for generating fluid pressure pulses are disclosed. An example apparatus may include a chamber that can collect fluid and an upstream ported disc coupled to a downstream end of the chamber. The upstream ported disc may rotate about a central axis. The upstream ported disc includes an upstream eccentric port that rotates about the central axis as the upstream ported disc rotates. The example apparatus may include a downstream ported disc coupled to a downstream end of the upstream ported disc such that the downstream ported disc remains substantially rotationally fixed relative to the upstream ported disc. The downstream ported disc includes a downstream eccentric port that may align with the upstream eccentric port to form a passageway for fluid to exit from the chamber to outside of the apparatus, at some time in a rotation cycle of the upstream ported disc.

Abstract: A system for communicating between a first location and a second location comprises a jointed tubular string having a first section and a second section connected at a connection joint, with the tubular string having a fluid in an internal passage thereof. A first acoustic transducer is mounted in the internal passage of the first section proximate the connection joint, and a second acoustic transducer is mounted in the internal passage of the second section proximate the connection joint. A signal transmitted from the first location to the second location is transmitted across the connection joint as an acoustic signal in the fluid from the first acoustic transducer to the second acoustic transducer.

Abstract: A rotary pulser for transmitting information to the surface from down hole in a well by generating pressure pulses encoded to contain information. The pressure pulses travel to the surface where they are decoded so as to decipher the information. The pulser includes housing containing a stator forming passages through which drilling fluid flows on its way to the drill bit, a rotor, and a replaceable wear sleeve enclosing the rotor. The rotor has blades that are capable of imparting a varying obstruction to the flow of drilling fluid through the stator passages depending on the circumferential orientation of the rotor, so that rotation of the rotor by a motor generates the encoded pressure pulses.

Abstract: An improved energy efficient intelligent rotary pulser for generating a mud pulse in a MWD (measurement while drilling) application. In the rotary pulser, a control circuit activates a brushless motor that rotates a windowed restrictor relative to a fixed housing to act as a shutter and window respectively. Opening of the windowed restrictor allows generally unrestricted mud flow. Closing of the windowed restrictor generally restricts mud flow. The windowed restrictor is powered both in opening and closing operations by the motor.

Abstract: An oscillating shear valve system for generating pressure fluctuations in a flowing drilling fluid comprising a stationary stator and an oscillating rotor, both with axial flow passages. The rotor oscillates in close proximity to the stator, at least partially blocking the flow through the stator and generating oscillating pressure pulses. The rotor passes through two zero speed positions during each cycle, facilitating rapid changes in signal phase, frequency, and/or amplitude facilitating enhanced, multivalent data encoding. The rotor is driven by a motorized gear drive. In one embodiment, a torsional spring is attached to the motor and the resulting spring mass system is designed to be near resonance at the desired pulse frequency. The system enables the use of multivalent encoding schemes for increasing data rates.

Abstract: A mud pulse telemetry system comprises a surface located fluid supply line having a drilling fluid flowing therein. A non-venting pulser is disposed in the drilling fluid in the supply line, and the non-venting pulser is adapted to generate pressure fluctuations in the flowing drilling fluid. A downhole receiver in hydraulic communication with the non-venting pulser is adapted to detect the pressure fluctuations in the drilling fluid. A method for transmitting pressure signals from a surface location to a downhole location in a wellbore, comprises disposing a non-venting pulser in a surface located fluid supply line having a drilling fluid flowing therein. The non-venting pulser is actuated to generate pressure fluctuations in the flowing drilling fluid according to a predetermined encoding scheme. The pressure fluctuations are detected with a downhole receiver in hydraulic communication with the non-venting pulser.

Abstract: Disclosed herein is a rotational pulsation system including a rotor having turbine blades to drive the rotor. A centralizer having coils and a stator package positioned to operably communicate with permanent magnets at the rotor and a rotational screen disk/static screen disk disposed at the rotor. A method for communicating in a wellbore includes spinning a rotational pulsation system to create a first frequency and applying and removing an electrical load according to a message to be communicated.

Abstract: A telemetry system involving a shear-type mud pulser valve as the preferred embodiment is described. The control system includes a motor driver for the mud pulser which, in essence, moves one movable plate with respect to a stationary plate to create openings of various sizes. Pressure is sensed uphole of the pulser valve and is compared in real time to the desired pressure pulse amplitude. By allowing different relative rotational positions of the rotatable plate with respect to the stationary plate, different amplitudes can be achieved to further enhance the transmission of data to the surface. The control system compensates for wear in the mud pulser valve itself as well as drastic changes in mud flow and pressure. The configuration is simple and not prone to fouling from grit or other particles in the mud.