Abstract: The present invention relates to telemetry apparatus and methods, and more particularly to acoustic telemetry apparatus and methods used in the oil and gas industry. More specifically, the invention relates to a method for enhancing a received signal transmitted by acoustic telemetry through a drill string by modifying the received signal by a multiplication of the received signal with a second waveform.

Abstract: A drill bit having a bit body includes one or more acoustic sensors that are configured to detect elastic waves when the drill bit is used for drilling a wellbore. The acoustic sensor may be configured to detect a sonic signature associated with a failure event. In further arrangements, the acoustic sensors may be configured to receive signals from a controlled acoustic source.

Abstract: A drill string component includes a box-end and a pin-end. Each end includes a signal transceiver, which are operably coupled together. Each signal transceiver communicates with another signal transceiver in another component to form a communication network in the drillstring. An end-cap may be placed in the central bore of the pin-end of a component to form an annular chamber between a side of the end-cap and a wall of the central bore of the pin-end when the end-cap is disposed in the central bore. In some embodiments, an electronics module may be placed in the annular chamber and configured to communicate with one of the signal transceivers. Accelerometer data, as well as other sensor data, at various locations along the drillstring may be sampled by the electronics module and communicated to a remote computer. Drillstring motion dynamics, such as vibration, may be determined based on the accelerometer data.

Abstract: Methods of determining borehole conditions using distributed measurement data are disclosed herein. The disclosed methods utilize real time data measurements taken from sensors distributed along the length of a drill string to assess various conditions or properties of the borehole. The disclosed methods of processing or using distributed measurement data have not been described before. In particular, the distributed data may be used for example, to track the progress of a chemical pill or also track the location of different types of borehole fluids, and also to determine the hole size or volume of the borehole.

Abstract: An embodiment includes a method comprising receiving an acoustic signal that is modulated along a jointed tubing. The method also includes performing equalization over a passband of the acoustic signal to generate an equalized signal.

Abstract: An acoustic telemetry system includes a piezoelectric stack at least partially disposed within a segment of pipe, and electrical circuitry for controlling the piezoelectric stack. In response to a signal from the electrical circuitry, the piezoelectric stack generates a plurality of acoustic signals for transmission through the pipe at different frequencies spanning multiple regions of a frequency response for the pipe.

Abstract: A pressure release encoding system for communicating downhole information through a wellbore to a surface location has 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, an actuator 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 sensor is an inclination sensor for sensing an angle of inclination of a drill bit in the wellbore.

Abstract: An acoustic sensor configured to detect sound waves traveling through a substrate in which the acoustic sensor is embedded. The acoustic sensor includes a piezoelectric element and mass configured to receive and react to sound waves in three dimensions. Also, methods of using the acoustic sensor to receive sound waves traveling through a substrate.

Abstract: A coaxial transmission line for an electromagnetic wellbore telemetry system comprises an outer conductive pipe, an inner conductive pipe disposed coaxially inside an axial bore of the outer conductive pipe, a first electrical contact having a first contact face disposed at a first end of the inner conductive pipe, a second electrical contact having a second contact face disposed at a second end of the inner conductive pipe, wherein at least one of the first and second contact faces includes at least one slot, and an insulator disposed between the outer conductive pipe and the inner conductive pipe.

Abstract: A system for communicating with a downhole network integrated into a downhole drill string is disclosed in one aspect of the invention as including a data transmission coupler mounted to a downhole tool and adapted to transmit data across a tool joint. The data transmission coupler is also capable of transmitting data by emitting electromagnetic radiation. An antenna is focused at and positioned within sufficient range of the data transmission coupler to detect the electromagnetic radiation and receive the data. This data may then be transmitted to a receiver or other equipment. In certain embodiments, the antenna is located above ground level and may be mounted to a swivel, derrick, hoist system, kelly, or other structure. The antenna is ideally mounted to a structure which is out of the way of equipment and workers working on the drill string.

Abstract: A shear coupled acoustic telemetry system. An acoustic telemetry system includes a tubular string having a pressure-bearing wall and an acoustic telemetry assembly positioned external to the wall and operative to communicate an acoustic signal between the assembly and the wall. The assembly may be shear coupled to the wall. The assembly may include a pressure-bearing housing positioned external to the wall.

Abstract: An acoustic telemetry system includes a piezoelectric stack at least partially disposed within a segment of pipe, and electrical circuitry for controlling the piezoelectric stack. In response to a signal from the electrical circuitry, the piezoelectric stack generates a plurality of acoustic signals for transmission through the pipe at different frequencies spanning multiple regions of a frequency response for the pipe.

Abstract: Methods and apparatus to configure drillstring communications are described. In one disclosed example, a method to configure drillstring communications involves generating a signal at a transmitter coupled to a drillstring, transmitting the generated signal via the transmitter to a receiver, sampling the transmitted signal at the receiver to generate a received signal, calculating a transmission characteristic based on a comparison of the generated signal and the received signal, and configuring at least one of the transmitter or receiver based on the transmission characteristic.

Abstract: The present invention provides a method and system in which signals from the surface are sent by changing flow rate of the drilling fluid supplied to the drill string during drilling of a wellbore. The signals are sent based on a fixed or dynamic time period schemes so that the sent signals cross a threshold value in a known manner. A detector measures the changes in the flow rate. A controller downhole determines the number of times a downhole parameter, such as voltage, relating to the changes in the flow rate crosses a predefined threshold value. Based on the number of the crossings and the timing of such crossings, signals are assigned to commands. The controller controls or operates a steering device based on the commands.

Abstract: An electrical system for use with a sucker rod pump includes an electric generator configured to be operated by motion of a sucker rod string. The rod string is configured to transfer motive power to the sucker rod pump disposed in a wellbore. The generator is disposed in the wellbore. The system includes at least one electrically powered device electrically coupled to the generator and disposed in the wellbore.

Abstract: A method and apparatus for estimating a change in length of a wellbore conveyance device in a wellbore. A reference signal is sent along a first path and a wellbore signal having a phase relationship with the reference signal is sent along a wellbore path. A change in length of the wellbore conveyance device is estimated from a phase shift between the reference signal and the wellbore signal. The frequency of the wellbore signal may be changed downhole. The wellbore conveyance device may have at least one conductor under a maintained tension. A length of the wellbore conveyance device is estimated from the estimated change in the length. For a drill string composed of a plurality of wellbore tubulars, a phase shift of the drill sting is determined upon adding a wellbore tubular to the drill string.

Abstract: A downhole communication apparatus has a signal coupler disposed in an end of a downhole tubular component. The signal coupler has a transceiver portion and a conductor portion. A data conductor integrated into the downhole tubular component is operably connected at a junction to the conductor portion of the signal coupler. A peripheral electronic device is in communication with the conductor portion of the signal coupler, either through an electrical coil wrapped around at least part of the conductor portion of the signal coupler or direct electrical contact with the conductor portion of the signal coupler.

Abstract: A while-drilling Vertical Seismic Profiling (VSP) data acquisition system utilizing the same seismic shots for three purposes is disclosed. First, the seismic shots provide a means for synchronizing a downhole clock in the VSP receiver to a master clock at the surface, thereby enabling correct determination of seismic travel times. Second, the same seismic shots are also used to communicate commands and other information to the downhole VSP receiver, such commands controlling the actions of the VSP receiver or associated devices. Third, the same seismic shots are utilized for purposes of the VSP survey itself, i.e. determination of seismic travel times, forming of seismic images, and determination of geologic and formation fluid properties using the VSP methods.

Abstract: A method of transmitting data acoustically through a tubular structure, such as a drill string or production tubing in an oil or gas well, predominantly comprising a series of tubing sections (1)joined end to end by couplings (2), at least a preponderance of the tubing sections having an axial length of at least a dimension X between couplings and at least a preponderance of the couplings having an axial length of no more than a dimension x, where X is substantially greater than x. The method comprises propagating acoustic signals along the structure, between transducers (9,10) over a distance N of at least 10X, in the form of tone bursts at least predominantly comprising a selected guided wave mode (preferably the L(0, 1) mode at low frequency) with a wavelength of at least 2x, and each burst having a temporal length of substantially less than 2N/C and preferably no more than 2X/C, where C is the phase velocity of the selected mode.

Abstract: A communications system employing discrete multi-tone (“DMT”) modulated signals on a communications channel formed by inductively-coupled pipe. In one embodiment, the communications system includes a string of wired pipe joints that couple a transmitter to a receiver. Each pipe joint in the string possesses threaded ends configured for mechanically connecting with other pipe joints, a electrical or inductive coupler at each threaded end, and an insulated conductor that electrically connects the couplers. The transmitter and receiver communicate via DMT modulated signals transported by the wired pipe string. The system may further include multiple repeaters in the string. Each repeater may be configured to receive a DMT-modulated signal, to recover information from the DMT-modulated signal, and to retransmit the information in the form of a DMT-modulated signal.

Abstract: Acoustic telemetry devices and methods that provide directional detection. In one embodiment, a disclosed acoustic telemetry device comprises at least two acoustic sensors and an electronics module.

Abstract: In one aspect of the invention, a high-speed measurement system has a first and a second well bore. A first and second plurality of network nodes is integrated into and spaced at intervals along the first and second well bore, respectively. A communications channel connects each plurality of network nodes forming a first and second downhole network. A signal source is in communication with the first downhole network and a signal receiver is in communication with the second downhole network; and a common clock source is in communication with both the signal source and the signal receiver over the first and second downhole networks, respectively. The signal source and signal receiver are synchronized with the clock source and the signal source is adapted to send a signal to the signal receiver through a subterranean formation.

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: Disclosed herein is a sensor system having a sensor and at least one communication line operable with the sensor. The transmission medium is configured to convey data transmitted by the sensor to a remote location. The sensor transmits data on the communication line a plurality of times by at least two methods of transmission or modulation. Further disclosed herein is a method based on the foregoing. Further disclosed is a method of communicating by modifying a voltage amplitude of a signal and receiving the communication signal by employing a variable threshold detection circuit in the downhole device. Further disclosed is a system for communicating data between a downhole device and a remote location including a remote device for generating a communication signal, the remote device configured to modify a voltage amplitude of said communication signal.

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 mud pulse landing assembly (10) which allows for the removal of the mud pulse generator (16) containing the mud pulse orifice (106), thus creating an unobstructed passageway for any tool or instrumentation that may need to be passed through the drill string. The retainer (14) of the mud pulse landing assembly also provides a universal mount for engaging alternate tools or instrumentation for use in analyzing the borehole geology. The retainer (14) is positioned between the mud pulse generator (16) and the landing sub body, so as to protect the retainer from the turbulent and abrasive mud flow, and to prevent obstruction of the area downstream of the compact muleshoe (60).

Abstract: One embodiment includes an apparatus that includes a piezoelectric transducer to generate an acoustic signal that is to modulate along a mandrel, wherein the piezoelectric transducer includes at least one piezoelectric element and at least one electrode that is without non-permanent joints.

Abstract: Measurements made with dual sensors (flow rate or pressure) are used to attenuate pump noise in a mud pulse telemetry system.

Abstract: In one aspect of the invention a drill bit assembly has a body portion intermediate a shank portion and a working portion, the working portion having at least one cutting element. A shaft is supported by the body portion and extends beyond the working portion. The shaft also has a distal end that is rotationally isolated from the body portion. In another aspect of the invention, a method for steering a downhole tool string has the following steps: providing a drill bit assembly attached to an end of the tool string disposed within a bore hole; providing a shaft extending beyond a working portion of the assembly; engaging a subterranean formation with a distal end of the shaft; and angling the drill bit assembly with the shaft along a desired drilling trajectory.

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: One embodiment includes a method comprising receiving an acoustic signal that is propagated along a drill string. The method also includes correlating the acoustic signal to a first stored acoustic signal representing a first symbol, wherein the first stored acoustic signal is acquired from a propagation along the drill string in an approximately noise free environment.

Abstract: The disclosure describes a method and apparatus for effectively communicating data along an acoustic transmission path. The method comprises driving an acoustic transmitter to send a data signal along the acoustic transmission path, where the signal is distorted by ambient noise. The distorted signal is input to a spaced apart plurality of sensors so that consequent time-delayed signals provide reinforcement of the basic signal and attenuation of the ambient noise component when combined.

Abstract: One embodiment includes an apparatus that includes a piezoelectric transducer to generate an acoustic signal that is to modulate along a mandrel, wherein the piezoelectric transducer includes at least one piezoelectric element and at least one electrode that is without non-permanent joints.

Abstract: Thermal expansion matching for an acoustic telemetry system. An acoustic telemetry system includes at least one electromagnetically active element and a biasing device which reduces a compressive force in the element in response to increased temperature. A method of utilizing an acoustic telemetry system in an elevated temperature environment includes the steps of: applying a compressive force to at least one electromagnetically active element of the telemetry system; and reducing the compressive force as the temperature of the environment increases.

Abstract: Acoustic telemetry systems and methods with surface noise cancellation. One illustrative embodiment may include an acoustic telemetry system comprising a transmitter configured to generate an acoustic information signal that propagates along a drillstring, and a receiver configured to detect an acoustic receive signal from the drillstring and a noise signal from a surface environment. The receiver operates on the acoustic receive signal and the noise signal to produce a modified signal indicative of the acoustic information signal and having a reduced noise content relative to the acoustic receive signal.

Abstract: One embodiment includes a method comprising receiving an acoustic signal that is propagated along a drill string. The method also includes correlating the acoustic signal to a first stored acoustic signal representing a first symbol, wherein the first stored acoustic signal is acquired from a propagation along the drill string in an approximately noise free environment.

Abstract: A downhole communication apparatus has a signal coupler disposed in an end of a downhole tubular component. The signal coupler has a transceiver portion and a conductor portion. A data conductor integrated into the downhole tubular component is operably connected at a junction to the conductor portion of the signal coupler. A peripheral electronic device is in communication with the conductor portion of the signal coupler, either through an electrical coil wrapped around at least part of the conductor portion of the signal coupler or direct electrical contact with the conductor portion of the signal coupler.

Abstract: The present invention is directed to overcoming analog transmission difficulties by digitizing transducer signals at or near the transducer of an acoustic pulse gun and then transmitting the transducer signals in a digital form so that the signals can be recovered with greater fidelity by a remote computer or recorder. System, apparatus and method aspects of the invention are provided. Advantages of the present invention include better transmission of the acoustic signal from the pulse gun assembly to the computer or recorder, reduced noise and electronic interference, and better data capture.

Abstract: A tubular component in a downhole tool string has a first end and a second end. The first end includes first and second inductive couplers, and the second end includes third and fourth inductive couplers. The component further has a first conductive medium and second conductive medium. The first conductive medium is connecting the first and third couplers, and the second conductive medium is connecting the second and fourth couplers. The first and second ends may include additional inductive couplers and the component may include an additional conductive medium connecting the additional couplers. A tubular component in a downhole tool string may have a first end and a second end and electronic equipment disposed in the component. The first end may have a first plurality of inductive couplers, and the component may further have a conductive medium connecting each inductive coupler of the first plurality of inductive couplers and the electronic equipment.

Abstract: A data transmission apparatus having first and second electrical conductors is disclosed. The first and second electrical conductors are disposed within recesses of a first and second complementary surfaces that are magnetically conducting and electrically insulating. The first and second surfaces are in close proximity to each other. The first surface is translatable along the length of the second surface. The first and second electrical conductors are in electromagnetic communication and provide for the transmission of data or power from the first electrical conductor to the second electrical conductor as the first surface overlaps the second surface. The data transmission apparatus may be located in one or more downhole tools.

Abstract: Methods and systems employing combined source-channel coding for multi-carrier modulation (MCM). In some embodiments, a described method comprises: estimating channel gain to noise ratio (CGNR) as a function of frequency bin; determining MCM parameters that minimize distortion of one or more telemetry signals; generating a communications signal using the MCM parameters, and transmitting the communications signal via a communications channel. The MCM parameters may be determined by minimizing a telemetry signal distortion measure subject to CGNR and a transmit power constraint. The MCM parameters may further account for differing fidelity requirements when multiple telemetry signals are being transmitted.

Abstract: A decision feedback equalizer (DFE) structure which uses a reference signal based adaptive equalizer as forward filter and a blind adaptive equalizer as feedback filter is used for surface processing of mud pulse telemetry data.

Abstract: A modulated reflectance well telemetry apparatus having an electrically conductive pipe extending from above a surface to a point below the surface inside a casing. An electrical conductor is located at a position a distance from the electrically conductive pipe and extending from above the surface to a point below the surface. Modulated reflectance apparatus is located below the surface for modulating well data into a RF carrier transmitted from the surface and reflecting the modulated carrier back to the surface. A RF transceiver is located at the surface and is connected between the electrically conductive pipe and the electrical conductor for transmitting a RF signal that is confined between the electrically conductive well pipe and the electrical conductor to the modulated reflectance apparatus, and for receiving reflected data on the well from the modulated reflectance apparatus.

Abstract: A telemetry system having: a pipe; a SCADA box acoustically coupled to the pipe; and a gauge inserted in the pipe, the gauge comprising: an acoustic wave generator; a coupler mechanically connected to the acoustic wave generator, wherein the coupler is engageable and disengageable with the pipe, wherein the coupler defines an acoustic transmission path between the acoustic wave generator and the pipe when engaged with the pipe; and a signal controller in communication with the acoustic wave generator. A method for communicating information in a wellbore from a downhole location to the surface, the method having the following steps: running a downhole gauge into a pipe within the wellbore, wherein the downhole gauge comprise an acoustic wave generator; setting the downhole gauge in the pipe; and communicating an acoustic signal between the downhole gauge and the pipe.

Abstract: A communications system employing discrete multi-tone (“DMT”) modulated signals on a communications channel formed by inductively-coupled pipe. In one embodiment, the communications system includes a string of wired pipe joints that couple a transmitter to a receiver. Each pipe joint in the string possesses threaded ends configured for mechanically connecting with other pipe joints, a electrical or inductive coupler at each threaded end, and an insulated conductor that electrically connects the couplers. The transmitter and receiver communicate via DMT modulated signals transported by the wired pipe string. The system may further include multiple repeaters in the string. Each repeater may be configured to receive a DMT-modulated signal, to recover information from the DMT-modulated signal, and to re-transmit the information in the form of a DMT-modulated signal.

Abstract: A casing sensor and methods for sensing using a casing sensor are disclosed. The casing sensor includes a casing shoe and a sensor coupled to the casing shoe. A casing data relay includes a downhole receiver coupled to a well casing and a transmitter coupled to the receiver. The casing sensor may be coupled to the transmitter. A drill string actuator may be controllable through the downhole receiver.

Abstract: An electromagnetic telemetry system for transmitting data from a downhole assembly, which is operationally attached to a drill string, to a telemetry receiver system. The data are typically responses of one or more sensors disposed within the downhole assembly. A downhole transmitter induces a signal current within the drill string. The signal current is modulated to represent the transmitted data. Induced signal current is measured directly with the telemetry receiver system. The telemetry receiver system includes a transformer that surrounds the path of the current, and an electromagnetic current receiver. The transformer preferably comprises a toroid that responds directly to the induced signal current. Output from the transformer is input to an electromagnetic current receiver located remote from the downhole assembly and typically at the surface of the earth.

Abstract: An electromagnetic borehole telemetry system for transmitting information between a borehole transceiver and a surface transceiver located at or near the surface of the earth. Tubulars, such as steel casing and liners, are typically set within the well borehole to stabilize the wall of the borehole and to assist in hydraulically isolating penetrated formations. The invention utilizes these tubulars cooperating with one or more signal wires to reduce attenuation and noise in signals transmitted between the borehole and surface transceivers. The one or more signal wires are typically disposed within an annulus formed by the borehole wall and the outside surface of the casing. The one or more signal wires are connected at one end to one or more connection terminals positioned preferably near the bottom a tubular string. Opposing ends of the one or more signal wires are connected to one or more terminals of the surface transceiver.

Abstract: A method and system for use in synchronizing at least two clocks in a downhole network are disclosed. The method comprises determining a total signal latency between a controlling processing element and at least one downhole processing element in a downhole network and sending a synchronizing time over the downhole network to the at least one downhole processing element adjusted for the signal latency. Electronic time stamps may be used to measure latency between processing elements. A system for electrically synchronizing at least two clocks connected to a downhole network comprises a controlling processing element connected to a synchronizing clock in communication over a downhole network with at least one downhole processing element comprising at least one downhole clock. Preferably, the downhole network is integrated into a downhole tool string.

Abstract: A method and system for telemetry through a compressible drilling fluid during underbalanced drilling is disclosed. A reflector (110) is positioned downstream from the gas inlet (84) and causes reflected pressure waves having the same pressure polarity as incident pressure waves. A pressure sensor (92) is positioned below the reflector to sense pressure in the compressible drilling fluid. The reflector (110) can be a fixed orifice plate or an adjustable aperture. A borehole communication system is also disclosed wherein a pair of pressure sensors are positioned on either side of a flow restriction (118) located in the gas conduit leading to the gas injector. The flow restriction can be a valve used to regulate the flow rate of the gas being supplied into the drilling fluid, or it can be separate venturi or orifice plate.