Abstract: A downhole telemetry system and method using discrete multi-tone modulation having repeated symbols. The system includes a surface receiver, a cable, and a downhole transmitter coupled to the surface receiver via the cable. The transmitter communicates a time-domain signal to the receiver. The time-domain signal has a cyclic prefix for a symbol at least as long as the length of the symbol. The system may alternatively include the time-domain signal having a symbol followed immediately by a copy of the symbol. The method includes receiving a time-domain signal carrying desired information at specific frequencies. The signal has at least one symbol. The method includes prepending a cyclic prefix having first length to the beginning of the symbol. The cyclic prefix has a second length no longer than the first length. The method may alternatively include appending a copy of the at least one symbol to the end of the at least one symbol.

Abstract: A downhole telemetry system that transmits a burst-QAM uplink signal to the surface of the well is disclosed. In a preferred embodiment, a downhole instrument coupled to a pair of conductors in a wireline or composite tubing string transmits a burst-QAM uplink signal to a surface system. The burst-QAM signal preferably comprises a series of data frames carrying telemetry data. Each data frame is preferably preceded by a quiet interval (when no signal is present), a timing synchronization sequence, and a training sequence. The timing synchronization sequence is designed for easy timing recovery at the surface, and the training sequence is designed to aid the adaptation of the equalizer. The data frame itself preferably includes a synchronization field, a data count, and a checksum in addition to the data. Direct digital synthesis is preferably employed to modulate the uplink signal.

Abstract: A system for protecting the transmission of signals from and/or to a tool in a high pressure environment. The system includes a tool connected to a signal transmission line, such as an electrical cable or optical fiber. The signal transmission line is surrounded by a protective tube that is connected to the tool by a connector having a hollow chamber in communication with the interior of the tube. A fluid, such as a dielectric liquid, is disposed within the connector and the tubing at a pressure higher than the environmental pressure. In the event of a leak at, for instance, the connector, the high pressure fluid flows outwardly rather than allowing the inflow of deleterious fluid from the environment.

Abstract: A system and method for enhancing the reception of electromagnetic (EM) waves in a fixed downhole receiver of an EM telemetry system is provided. In one embodiment, slots are formed in a portion of an outer casing and an EM receiver is positioned within the outer casing so as to be aligned with the slots formed therein. In another embodiment, an inductive coupling arrangement is provided to transfer signals from an EM receiver mounted on the outside surface of an outer casing to a wireline that is attached to the outer surface of an inner casing, which is disposed within the outer casing. In yet another embodiment, an insulated gap is formed in the surface of the outer casing. An EM receiver, mounted on the outer surface of the inner casing, is positioned above the insulated gap of the outer casing. An electrical coupling mechanism is further provided to electrically couple the inner and outer conductors at a point above the EM receiver.

Abstract: Proposed is a method for transmitting data from at least one sensor to a control unit via an appropriate two-wire line, the method being used to identify any sensor at the control unit and to implement a plurality of logical channels via the appropriate two-wire line. The at least one sensor receives the necessary electrical energy from the control unit via the two-wire line and then transmits the sensor-specific data.

Abstract: The invention consists of a downhole data transmission line, and a method of making the same, having at least one polymeric or glass fiber, a first containment tube surrounding the fiber, a conductive material wrapped or braided around the first tube, a layer of insulating material covering the conductive material, and a second containment tube surrounding the insulating material. The downhole transmission line preferably uses optical fibers, a stainless steel first and metal alloy second tubes, copper braiding for the conductive material, thermoplastic for the insulating material, and a protective layer surrounding the outer second tube. A well for producing oil or gas from an oil or gas reservoir that includes the data transmission line and a system for sensing and recording physical parameters over an extended distance that includes the data transmission line are described. The invention also includes methods of using the data transmission line.

Abstract: Disclosed are systems and methods for indicating events at various locations in a power distribution system.

Abstract: An electrical submersible pump cable having an integral capacitor. The electrical submersible pump cable has a primary conductor with an insulator surrounding the primary conductor. A coaxial conductive layer surrounds the insulator, wherein the insulator serves as a dielectric between the primary conductor and the coaxial conductive layer. An outer insulating sleeve is provided on an outer surface of the coaxial conductive layer. An inner cable armor surrounds the insulating sleeve, wherein the outer insulating sleeve provides electrical isolation between adjacent wires. An outer cable armor surrounds the inner cable armor. The coaxial conductive layer and primary conductor enables the coupling of data information onto or off of the cable.

Abstract: A system and method for downhole power delivery. In one embodiment, the system delivers computer-regulated downhole power voltages, and may be configured to customize signal waveforms and power allocation on the various independent signal transmission modes to maximize the power capacity of the logging cable subject to its maximum voltage rating. In one embodiment, the system includes a standard multiconductor logging cable which supports orthogonal signal transmission modes on circumferentially spaced insulated conductors. A high-power power source on the surface is coupled to the insulated conductors in the cable to drive a power signal on the lowest impedance signal transmission mode. The system may further include multiple power sources operating on different independent signal transmission modes, and may also include multiple telemetry channels which share the power transmission modes via frequency multiplexing.

Abstract: The present invention provides apparatus and methods for controlling and/or powering downhole components without the need for control and/or power lines extending from the components to the surface of the well and without the need for power or control lines to be inserted into the wellbore along with the components. In one aspect of the invention, a borehole is lined with a casing, the casing having at least one aperture disposed. Adjacent the aperture, on the outer surface of the casing, is a docking station, which is permanently attached to the casing and includes a socket. After the casing is installed in the borehole, a downhole component can be lowered into the wellbore. The downhole component is equipped with a connector extending from an outer surface thereof. The connector assembly is disposable through the aperture in the casing and, the connector assembly can be connected to the socket of docking station.

Abstract: A borehole telemetry system including a surface telemetry module, a downhole telemetry module, and a multiplexed datalink between the surface and downhole modules capable of transferring data alternately between an uplink in which date is transferred from the downhole module to the surface module and a downlink in which data is transferred from the surface module to the downhole module; wherein the data link can be switched between a first configuration in which a relatively long time is assigned to the uplink and a relatively short time is assigned to the downlink, and a second configuration in which a relatively long time is assigned to the downlink and a relatively short time is assigned to the uplink. The first configuration can be used to transmit data when logging with downhole tools and the second configuration can be used to program logging tools.

Abstract: An improved data telemetry system for multi-conductor wirelines to achieve satisfactory transmission of analog and digital signals with frequency content up to 100 kHz by assigning at least two conductors to a first terminal of a data transmittal means and to a first terminal of a data receiver means and connecting at least one additional conductor to a second terminal of a data transmittal means and to a second terminal of a data receiver means. Pairing conductors reduces attenuation and crosstalk and permits the signal to contain multiple frequency modulated carrier bands with individual channel bandwidths of up to 3 kHz or higher.

Abstract: A system and method is described for safely and economically providing up to 1800 watts to downhole equipment over existing logging cables. In one embodiment, the system includes a standard multiconductor logging cable which supports orthogonal signal transmission modes on circumferentially spaced insulated conductors. A high-power power source on the surface is coupled to the insulated conductors in the cable to drive a power signal on the lowest impedance signal transmission mode. Bearing in mind that high-power electrical currents can present a safety hazard, system safety may be enhanced by the addition of a reliable current imbalance detector configured to shut down all power sources when currents in the insulated conductors don't add up to zero. The system may further include multiple power sources operating on different independent signal transmission modes, and may also include multiple telemetry channels which share the power transmission modes via frequency multiplexing.

Abstract: A communication system between remote locations connected by a common wire conductor where AC power (40) is supplied from one location to one or more remote locations (32 and 34). At the remote locations, inductor coil components (28,32) and (30,34) provide power to an instrument (24,26). The AC power is modulated with surface selected discrete frequencies (56) to operate a specific selected remote location. At the selected remote location (24), the AC power is rectified and a logic processor detects the discrete frequencies for that location and operates the instrument. Data from the instrument is translated by current modulation (60) which is demodulated at the one location (50,64,66,68,70).

Abstract: An electrical submersible pump cable having an integral capacitor. The electrical submersible pump cable has a primary conductor with an insulator surrounding the primary conductor. A coaxial conductive layer surrounds the insulator, wherein the insulator serves as a dielectric between the primary conductor and the coaxial conductive layer. An outer insulating sleeve is provided on an outer surface of the coaxial conductive layer. An inner cable armor surrounds the insulating sleeve, wherein the outer insulating sleeve provides electrical isolation between adjacent wires. An outer cable armor surrounds the inner cable armor. The coaxial conductive layer and primary conductor enables the coupling of data information onto or off of the cable.

Abstract: A downhole string includes a system having an actuator module that is responsive to electrical power and signals communicated down a cable, such as a permanent downhole cable (PDC). In addition, a backup mechanism, such as an inductive coupler mechanism or another type of wireless apparatus, can be used as a backup to restore power and communications with the downhole system. For example, if the cable fails for some reason, power and signals can still be communicated with the inductive coupler mechanism or other wireless mechanism to control operation of the system or to receive signals from the system.

Abstract: A downhole telemetry system having discrete multi-tone modulation and dynamic bandwidth allocation is disclosed herein. In one embodiment, the downhole telemetry system comprises a surface transceiver, a cable, and a downhole transceiver coupled to the surface transceiver via the cable. The downhole transceiver communicates to the surface transceiver using discrete multi-tone (DMT) modulation to transmit telemetry information over a set of frequency subchannels allocated for uplink communications. The surface transceiver may likewise communicate to the downhole transceiver using DMT modulation to transmit information over a set of frequency subchannels allocated for downlink communications. The number of uplink and downlink communications subchannels is preferably variable and preferably can be changed depending on the operating mode of the system.

Abstract: A method and apparatus for determining position in a pipe provides for the precise determination of location and associated characteristics of each pipe joint of a well, cross country pipeline or other fluid transmission line. The system includes a passive or active radio identification device at each joint in the pipe or casing string. The devices are preferably sealed within the resilient seal positioned between each pipe or casing joint. A pipeline tool includes a radio transmitter and receiver, with the transmitter transmitting on a frequency selected for resonating the identification devices. The resonant response of each device is detected by a receiver in the pipeline tool, with the response transmitted to the surface via the wireline to which the tool is connected. Alternatively, the tool may include storage information means until the tool can be recovered from the well or pipe.

Abstract: An annular wire harness for use in drill pipe comprising two rings interconnected by one or more insulated conductors. The rings are positioned within annular grooves located within the tool joints and the conductors are fixed within grooves along the bore wall of the pipe. The rings may be recessed within annular grooves in order to permit refacing of the tool joint. The rings are provided with means for coupling a power and data signal from an adjacent pipe to the conductors in such a fashion that the signal may be transmitted along the drill pipe and along an entire drill string.

Abstract: A method and apparatus for implementing a communication network for well monitoring and control applications where a twisted pair cable bus is used to connect well-related locations. The twisted pair cable bus will exhibit high parallel impedance when used in differential mode and low series impedance in common mode. A bus supervisor and devices connected at nodes can exchange signal transmission. Communication, including data and control, signals and power signals can circulate along the twisted pair cable bus among and between the connected devices.

Abstract: A downhole telemetry system that transmits a burst-QAM uplink signal to the surface of the well is disclosed. In a preferred embodiment, the well includes composite tubing having circumferentially-spaced electrical conductors helically wound within the walls of the tubing. A downhole instrument coupled to a pair of adjacent conductors transmits a burst-QAM uplink signal to a surface system similarly coupled to the pair of adjacent conductors. The burst-QAM signal preferably comprises a series of data frames carrying telemetry data. Each data frame is preferably preceded by a quiet interval (when no signal is present), a timing synchronization sequence, and a training sequence. The timing synchronization sequence is designed for easy timing recovery at the surface, and the training sequence is designed to aid the adaptation of the equalizer. The data frame itself preferably includes a synchronization field, a data count, and a checksum in addition to the data.

Abstract: A reliable, high data rate, downhole acoustic telemetry system is disclosed. In one embodiment, the acoustic telemetry system includes a tubing string with an acoustic transmitter and an acoustic receiver mounted on it. The acoustic transmitter transmits telemetry information by modulating an acoustic carrier frequency that propagates along the walls of the tubing string. The transmitter is preferably mounted at a selected position relative to the end of the tubing string. The selected position is preferably less than &lgr;/4 from the end or approximately n&lgr;/2 from the end, where &lgr; is the wavelength of the carrier frequency in the tubing string, and n is a positive integer. In a more preferred embodiment, n may be the lesser of 4 times the number of cycles in the modulating toneburst and 40. The receiver is preferably mounted at approximately (2n−1)&lgr;/4 relative to the end of the tubing string, where n is a positive integer.

Abstract: Disclosed is a downhole video system that is suitable for use with a standard wireline transmission line, without the need for coaxial or fiber optic cable. A downhole video camera transmits a digitized video signal that may be multiplexed with orientation, sound, and other telemetry data. At the surface, an enhanced video is displayed simultaneously with processed sound to give an operator a better understanding of the conditions downhole. In addition, multiple modes are provided, including a “burst” mode to provide high resolution, full motion video, thereby circumventing the severe bandwidth limitations of standard electrical transmission lines.