Abstract: The present invention utilizes signals such as interrogate commands generated from a Master Clock or other High Precision Clocks in a distributed sensor data acquisition system featuring a communications network (such as a land/transition zone seismic data acquisition system) to stabilize the oscillator (timing cycle) frequency of Remote Clocks elsewhere in the network. The disclosed invention is characterized by the utilization of highly stable timing signals from a Master Clock or other High Precision Clocks as a calibration standard to improve the oscillator frequency of distributed Remote Clocks of lesser inherent stability. Implementation of the disclosed invention results in improved synchronization of seismic amplitude data concurrently acquired over a wide area and improved subsurface geologic resolution.

Abstract: A cable link may include a first link connector in signal communication with at least one sensor in a drill string and coupled to the drill string, a second link connector spaced apart from the first link connector and in signal communication with a telemetry system, the second connector link coupled to the drill string, and a linking cable having signal connectors at each end thereof, the linking cable having at least one of an electrical conductor and an optical fiber therein, the signal connectors each configured to latch proximate a respective one of the first and second link connector.

Abstract: In the present invention, a seismic receiver contains an onboard digitizer that samples and converts a signal from detected seismic energy into the digital domain. The receiver contains an analog to digital converter, a transmission circuitry, and a link to the seismic detection circuitry. The signal from the seismic detection circuitry is converted into a digital signal, which is then relayed to the data recorder. These components are all resident to the receiver itself. Additional control circuitry is employed to provide clocking and testing functions. These receivers communicate with one another, and provide sampled seismic data on an individual basis. The components may be prepared on a PCB and put inside the receiver cap. The PCB may be flexible in nature, as to provide a maximum of surface mounted components in the smallest amount of space.

Abstract: The present invention provides a method and apparatus for a segmented antenna system. The method includes determining an orientation of a first antenna, the first antenna including a plurality of segments for transmitting and receiving signals, determining a direction from the first antenna to a second antenna capable or at least one of transmitting and receiving signals, and selecting at least one of the plurality of segments of the first antenna using the determined orientation of the first antenna and the determined direction.

Abstract: A system and method for acquiring seismic data is provided that utilizes a plurality of field station (data acquisition) units placed over a region of interest and a remote central unit. The system and method, in one aspect, determine a condition associated with each of a plurality of preselected attributes relating to the acquisition of the seismic data at each of the field station units, generate messages at each field station when the condition of any particular attribute meets a selected criterion, and transmit the generated messages to a remote unit wirelessly. The system and methods provide efficient use of the available bandwidth and avoid collisions among messages transmitted simultaneously by several field station units. 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.

Abstract: A system and methods for acquiring seismic data is provided. In one aspect, the system and methods utilize a plurality of field service units placed over a region of interest, a repeater unit that wirelessly communicates with the field service units and a remote unit for controlling and processing the seismic data acquired by the field service units. In one aspect, the system and methods determine a condition associated with each of a plurality of attributes relating to acquisition of the seismic data at each field service unit, generate messages at each field service unit when the condition of a particular attribute meets a selected criterion, transmit the generated messages, receive the messages transmitted by at least a group of field service units at a repeater unit placed in the region of interest, analyze the messages received from the group of field service units at the repeater unit and then transmit information relating to the received messages to the remote unit for further processing.

Abstract: An apparatus and method is disclosed for establishing a one-time cryptographic pad between a communicating pair, a communicating pair comprising a pair of transmitter-receivers, each of the pair having a plurality of cryptographic devices in common. The communicating pair also store previously exchanged messages and transmissions, a transmission comprising secure data exchanged by the pair that is independent of message content. The first transmitter-receiver randomly selects a cryptographic device and a previous transmission or message that has been sent to the second transmitter-receiver. The first transmitter-receiver also randomly selects a reference to a message or transmission previously sent by the second transmitter-receiver. The first transmitter-receiver encrypts the previously sent transmission or message and the reference to the message or transmission previously sent by the second transmitter-receiver and sends to the second transmitter-receiver.

Abstract: A technique for providing short circuit protection in electrical systems used in hydrocarbon exploration and production and, more particularly, for such electrical systems comprising serially connected nodes, includes an apparatus and method. The apparatus, includes a power supply and a plurality of electrically serially connected application sensors downstream from the power supply. Each application sensor includes a sensing element; and a plurality of electronics associated with the sensing element. The electronics shut off upstream power to the downstream application sensors in the presence of a short circuit. The method includes serially supplying power to a downhole apparatus comprising a plurality of electrically serially connected downhole sensors; sensing, in series and upon receiving power from upstream, at each downhole sensor whether a downstream short circuit exists; and shutting off upstream power to the downstream downhole sensors in the presence of a short circuit.

Abstract: Various technologies for a seismic acquisition system, which may include an acquisition central system configured to determine a desired start time for a sweep cycle in one or more vibrators and a recorder source system controller in communication with the acquisition central system. The recorder source system controller may be configured to receive the desired start time from the acquisition central system. The seismic acquisition system may further include one or more vibrator units in communication with the recorder source system controller. Each vibrator unit may be configured to start a sweep cycle in a vibrator at the desired start time.

Abstract: A self-contained data acquisition unit is provided for acquiring seismic data. The unit has a microprocessor and an antenna adapted to receive an electromagnetic signal. A decoder is connected with the microprocessor and adapted to convert received electromagnetic signals to dual-tone multiple-frequency (“DTMF”) digits. A geophone interface is provided with a geophone for collecting acoustic data incident on the geophone. A memory is connected with the geophone interface for storing a representation of the collected acoustic data and for storing a representation of a reference electromagnetic signal to be used in synchronizing acoustic data collected by other data acquisition units. A battery power source is connected with the microprocessor.

Abstract: A network distributed seismic data acquisition system comprises seismic receivers connected to remote acquisition modules, receiver lines, line tap units, base lines, a central recording system and a seismic source event generation unit synchronized to a master clock. One or more high precision clocks is added to the network to correct for timing uncertainty associated with propagation of commands through the network. Seismic receivers and seismic sources are thereby synchronized with greater accuracy than otherwise possible. Timing errors that interfere with the processing of the seismic recordings are greatly reduced, thus enabling an improvement in subsurface geologic imaging.

Abstract: A seismic survey system having remote acquisition modules (RAMs) for acquiring seismic signals and communicating with a central recording system (CRU) via a network of cables, other RAMs, and line tap units (LTUs), arranged in a matrix of receiver lines and base lines. Each RAM cyclically converts analog signal values to digital, forming data packets. Interrogation commands emanating from the CRU and relayed with strategic delays by intervening LTUs and RAMs are received by the RAM. Each command causes the RAM to transmit a data packet. Strategic delays are set such that the transmission capacity of the line is best utilized. Power and frequency of transmission are selectable by the CRU to optimize performance. Cables contain multiple communication pairs. The network path between the RAM and the CRU is established from the CRU and altered in event of malfunction. All types of network elements are interconnectable. Recorded samples are synchronous.

Abstract: A seismic survey system having remote acquisition modules (RAMs) for acquiring seismic signals and communicating with a central recording system (CRU) via a network of cables, other RAMs, and line tap units (LTUs), arranged in a matrix of receiver lines and base lines. Each RAM cyclically converts analog signal values to digital, forming data packets. Interrogation commands emanating from the CRU and relayed with strategic delays by intervening LTUs and RAMs are received by the RAM. Each command causes the RAM to transmit a data packet. Strategic delays are set such that the transmission capacity of the line is best utilized. Power and frequency of transmission are selectable by the CRU to optimize performance. Cables contain multiple communication pairs. The network path between the RAM and the CRU is established from the CRU and altered in event of malfunction. All types of network elements are interconnectable. Recorded samples are synchronous.

Abstract: A seismic survey system having remote acquisition modules (RAMs) for acquiring seismic signals and communicating with a central recording system (CRU) via a network of cables, other RAMs, and line tap units (LTUs), arranged in a matrix of receiver lines and base lines. Each RAM cyclically converts analog signal values to digital, forming data packets. Interrogation commands emanating from the CRU and relayed with strategic delays by intervening LTUs and RAMs are received by the RAM. Each command causes the RAM to transmit a data packet. Strategic delays are set such that the transmission capacity of the line is best utilized. Power and frequency of transmission are selectable by the CRU to optimize performance. Cables contain multiple communication pairs. The network path between the RAM and the CRU is established from the CRU and altered in event of malfunction. All types of network elements are interconnectable. Recorded samples are synchronous.

Abstract: A system and method for measuring the value of a parameter, e.g. sound energy, at a plurality of spaced locations using electrically powered microcells positioned at each of the locations and for transmitting RF signals commensurate with control and measurement data between a control node and the microcells, all without physical connection of a wiring harness, or the like, for either powering or signaling. The microcells and control node are mounted to an elongated, tubular member through which a single, insulated conductor and a coaxial cable in coupled mode extend, in proximity to the spaced microcells. The insulated conductor is connected to a source of AC power and passes through the open centers of current transformers which inductively couple the AC power to each microcell. A phase locked loop at each microcell controls the frequency of the AC power provided to the sensing element, thereby controlling the sampling rate.

Abstract: A seismic survey system having remote acquisition modules (RAMs) for acquiring seismic signals and communicating with a central recording system (CRU) via a network of cables, other RAMs, and line tap units (LTUs), arranged in a matrix of receiver lines and base lines. Each RAM cyclically converts analog signal values to digital, forming data packets. Interrogation commands emanating from the CRU and relayed with strategic delays by intervening LTUs and RAMs are received by the RAM. Each command causes the RAM to transmit a data packet. Strategic delays are set such that the transmission capacity of the line is best utilized. Power and frequency of transmission are selectable by the CRU to optimize performance. Cables contain multiple communication pairs. The network path between the RAM and the CRU is established from the CRU and altered in event of malfunction. All types of network elements are interconnectable. Recorded samples are synchronous.

Abstract: A seismic data acquisition system includes a connector housing and a mating electrical circuitry module. A single interface couples electrical circuitry housed in the electrical circuitry module to one or more signal data carriers that are consolidated at a single location in the connector housing. Preferably, the connector housing and electrical circuitry module each have a substantially contaminant-free interior regardless of whether these two parts are mated. An alternate connector housing has two plug casings, each of which are provided with a plug. A complementary alternate electrical circuitry module includes two receptacles complementary to the plugs and an interior space for holding the electrical circuitry. A locking pin disposed within the plug casing selectively engages the electrical circuitry module.

Abstract: A seismic survey system having remote acquisition modules (RAMs) for acquiring seismic signals and communicating with a central recording system (CRU) via a network of cables, other RAMs, and line tap units (LTUs), arranged in a matrix of receiver lines and base lines. Each RAM cyclically converts analog signal values to digital, forming data packets. Interrogation commands emanating from the CRU and relayed with strategic delays by intervening LTUs and RAMs are received by the RAM. Each command causes the RAM to transmit a data packet. Strategic delays are set such that the transmission capacity of the line is best utilized. Power and frequency of transmission are selectable by the CRU to optimize performance. Cables contain multiple communication pairs. The network path between the RAM and the CRU is established from the CRU and altered in event of malfunction. All types of network elements are interconnectable. Recorded samples are synchronous.

Abstract: In the present invention, a seismic receiver contains an onboard digitizer that samples and converts a signal from detected seismic energy into the digital domain. The receiver contains an analog to digital converter, a transmission circuitry, and a link to the seismic detection circuitry. The signal from the seismic detection circuitry is converted into a digital signal, which is then relayed to the data recorder. These components are all resident to the receiver itself. Additional control circuitry is employed to provide clocking and testing functions. These receivers communicate with one another, and provide sampled seismic data on an individual basis. The components may be prepared on a PCB and put inside the receiver cap. The PCB may be flexible in nature, as to provide a maximum of surface mounted components in the smallest amount of space.

Abstract: A seismic sensor cable is disclosed. The cable includes an outer jacket disposed on an exterior of the cable. The outer jacket excludes fluid from entering an interior of the cable. A reinforcing layer disposed within the outer jacket, which includes at least one electrical conductor disposed therein. An inner jacket is disposed within the reinforcing layer, and at least one electrical conductor disposed within an interior of the inner jacket. Some embodiments include at least one seismic sensor electrically coupled to the at least one electrical conductor disposed in the reinforcing layer In some embodiments a housing is disposed over the electrical coupling of the sensor to the conductor. The housing is molded from a polyurethane composition adapted to form a substantially interface-free bond with the cable jacket when the polyurethane cures.

Abstract: The present invention provides a method and apparatus of acquiring and processing seismic data. One or more controllers are each coupled to seismic sensors and to each other to form a network of data acquisition units. A main controller is coupled to a crossline unit via a cable comprising a synchronizing conductor and one or more power/data conductors. Commands and data are packaged such that multiple routings are possible without affecting final calculations. Each crossline unit is capable of accepting a fiber optic input, a wire input or a combination.

Abstract: A seismic survey system having remote acquisition modules (RAMs) for acquiring seismic signals and communicating with a central recording system (CRU) via a network of cables, other RAMs, and line tap units (LTUs), arranged in a matrix of receiver lines and base lines. Each RAM cyclically converts analog signal values to digital, forming data packets. Interrogation commands emanating from the CRU and relayed with strategic delays by intervening LTUs and RAMs are received by the RAM. Each command causes the RAM to transmit a data packet. Strategic delays are set such that the transmission capacity of the line is best utilized. Power and frequency of transmission are selectable by the CRU to optimize performance. Cables contain multiple communication pairs. The network path between the RAM and the CRU is established from the CRU and altered in event of malfunction. All types of network elements are interconnectable. Recorded samples are synchronous.

Abstract: A method is provided for accurately determining the physical location of a deployed seismic geophone used in seismic investigations by using a portable navigational satellite receiver to obtain a set of navigational satellite measurements providing the position of the deployed geophone at the time of deployment of the geophone into the earth. A method is provided for automatically and accurately identifying and determining the physical location of a deployed geophone used in seismic investigations by using one or more portable navigational satellite receivers and an automatic geophone identification and tracking system at the time of geophone deployment.

Abstract: The present invention is a method of transmitting one or more acoustic signals in a drill string using PSK, ASK, FSK or MSFK. The method includes determining one or more stopbands and one or more passbands by testing or modeling the drill string. Two modulating frequencies are selected that are equidistant about a carrier frequency, and which are located within at least one passband. Data representative of downhole measurements or calculations are converted to signals to be transmitted at the modulating frequencies.

Abstract: An acoustic isolator for attenuating through-tool acoustic signals comprises a plurality of u-shaped link members, where each link member has two sets of ears. A plurality of yoke members are adapted to fit between cooperating sets of ears. A plurality of pins connect the plurality of u-shaped link members to the plurality of yoke members for providing limited flexural compliance. The isolator may be made from metallic and/or composite materials.

Abstract: A seismic data acquisition technique comprises laying a seismic data cable having a plurality of spaced apart connection nodes and a plurality of sensor strings connected to the connection nodes along a line of the area to be seismically surveyed. Each sensor string comprises ten or more seismic sensors for producing respective output signals representative of a seismic signal received by them. The sensors of the sensor strings are laid out in at least two sets of groups, each group containing several of the sensors and transmitting at least one seismic signal to a connection node, and the sets of groups being disposed along respective spaced apart lines generally parallel to the line along which the seismic data cable is laid.

Abstract: The present invention provides a method and apparatus of acquiring and processing seismic data. One or more controllers are each coupled to seismic sensors and to each other to form a line of data acquisition units. A main controller is coupled to a crossover line unit and to a power supply. Power and data control is distributed among the main controller, the crossover line unit, and each of the plurality of data acquisition units.

Abstract: The present invention provides a semi-passive two-way borehole communication system and method. The system includes a surface source signal generator for generating an acoustic signal. The acoustic source signal is transmitted downhole, and a downhole controllable reflector reflects a portion of the source signal back toward the surface. The reflector is controlled such that an echo signal is created, which contains information to be carried to the surface. A surface receiver is used to detect the echo signal, and a surface controller is used to decode the echo signal.

Abstract: A two-conductor bidirectional digital telemetry interface between a seismic sensor acquisition/conversion module and a seismic data collection module. The data collection module is configured as a master electronics device and the sensor acquisition/conversion module is configured as a slave electronics device in the telemetry system. The master device provides power to the slave device over the two conductors. The master device transmits portions of commands to the slave device at a first time and the slave device transmits portions of a digital seismic data packet to the master at a different second time in a fixed-duration frame. The frames are transmitted at regular intervals. The outbound commands and inbound data are encoded by block codes. A phase-locked loop in the slave is locked to a master clock in the master by deriving a clock and a sync point from the block-coded commands it receives from the master.

Abstract: A seismic data acquisition system includes a connector housing and a mating electrical circuitry module. A single interface couples electrical circuitry housed in the electrical circuitry module to one or more signal data carriers that are consolidated at a single location in the connector housing. Preferably, the connector housing and electrical circuitry module each have a substantially contaminant-free interior regardless of whether these two parts are mated. An alternate connector housing has two plug casings, each of which are provided with a plug. A complementary alternate electrical circuitry module includes two receptacles complementary to the plugs and an interior space for holding the electrical circuitry. A locking pin disposed within the plug casing selectively engages the electrical circuitry module.

Abstract: A system is presented for detecting downhole generated telemetry pressure pulses in a well. The system employs high sensitivity dynamic pressure sensors such as hydrophones for detecting the pulses in either the surface drilling fluid supply line or in the fluid return annulus. The high sensitivity allows detection of smaller surface pulses than standard transducers. In one embodiment, an annular pulser is used to generate pulses directly in the annulus.

Abstract: An apparatus and system for integrating acoustic pods within marine seismic streamers. The integrated acoustic pod eliminates the attachment and detachment of acoustic pods from the streamer exterior surface when the seismic streamers are deployed into and retrieved from the water. Control electronics are integrated within the streamer interior and receive electric power from a streamer electrical conductors and receive control signals from a streamer control wire. The control electronic components can be integrated within the streamer interior or within modules connecting each streamer section. Acoustic transducer elements can extend through the connector module or can be attached to the connector module exterior. The acoustic transducer elements can be oriented to steer transmission of acoustic energy into the water, such as in a horizontal azimuth, and to permit correction of the steering direction.

Abstract: A noise-immune electronic circuit includes an input circuit for receiving an inbound signal through an input transmission line and comparing the inbound signal with a decision threshold to produce input data of the electronic circuit having one of predefined discrete levels depending on relative magnitudes of the inbound signal and the decision threshold and an output circuit for receiving output data of the electronic circuit and producing therefrom an outbound signal and forwarding the outbound signal onto an output transmission line. The input and output transmission lines are inductively coupled together so that a noise is introduced to the received inbound signal when a voltage transition occurs in the forwarded outbound signal.

Abstract: An underwater cable arrangement comprises an underwater cable capable of being towed through the water, an external device for mounting on the exterior of the cable, and a coil support device disposed inside the cable for supporting a coil. In some embodiments, the coil support device and the external device have engaging portions which co-act with each other to prevent relative rotation of the coil support device and the external device about the longitudinal axis of the cable. In some embodiments, the underwater cable has a skin and the external device is positioned around the coil support device with the skin of the underwater cable between them. The coil support device and the external device have an interference fit with respect to each other to resist relative movement to the coil support device and the external device in the longitudinal direction of the cable.

Abstract: The present invention provides a system for drilling boreholes having a downhole subassembly which contains an acoustic measurement-while-drilling system. It uses the acoustic velocity through the formations surrounding the borehole and an acoustic transmitter and a set of receivers for determining the bed boundaries surrounding the borehole formation. Semblance of the data is determined in a slowness/intercept-time domain. Coherence and semblance filtering methods are used to differentiate between reflection signals and noise. The position and orientation of the bed boundary relative to the tool are determined. A further processing step uses the relative position and orientation determined for a number of tool positions to further discriminate against noise and obtain an absolute position and depth of the bed boundaries.

Abstract: A technique and a system provide control and monitoring of devices external to a marine seismic streamer by segmenting the conductor to which the external devices are coupled. The module which connects sections of the seismic data telemetry cable is modified to include a switch. The switch is controlled by a command signal on the seismic data telemetry cable to segment the twisted pair bus into a plurality of dedicated busses, each dedicated to a subset of the external devices, such as one or two such devices. In this way, the external devices can be communicated with in parallel, rather than in series as in conventional systems.

Abstract: A seismic data acquisition system is featured that utilizes a series of nearly identical seismic shots (SISS) to synchronize and to communicate with novel data acquisition units (NDAU) located in the field. Each SISS seismic shot is carefully timed to provide synchronization to each NDAU, and to allow the NDAU to correct for the time drift of its internal clock. Further, each NDAU is programmed with a number of menus, which are used to interpret the seismic shots received from a seismic source. Thus, communication from a central or headquarter site to each NDAU is facilitated, allowing for a change in production schedule and other variables. In addition, the disclosed seismic data acquisition system features movable SISS source sites and overlapping production and SISS shots.

Abstract: A system and method for synchronizing collection of seismic data used for seismic surveys. In one embodiment, positioning signals received from a positioning system, such as the Global Positioning System, are used to acquire a highly accurate time value. Data collection is then initiated at a prespecified time using the time determined from the positioning signal.

Abstract: The invention is a seismic acquisition system for communicating seismic sensor signals to a recording unit, including a control unit and analog-to-digital conveyer units connected to the control unit. The conveyer units each include integral interconnecting cables having an hermaphroditic connector at each end, analog seismic sensor inputs and signal processing circuitry disposed within a watertight housing forming part of the cables. The circuitry includes analog-to-digital conveyers connected to the analog inputs, a buffer for digitized signals transmitted to one converter unit from other converter units interconnected to the conveyer unit opposite to the control unit connection, a digital transceiver for retransmission of digitized sensor signals and the buffered signals at a first data rate to the control unit. The control unit includes a second buffer for signals from the conveyer unit and for signals retransmitted from other control units serially codected to the control unit.

Abstract: A seismic data acquisition system utilizing a plurality of remote units, each remote unit being coupled to a plurality of receivers placed spaced apart on the earth's surface is provided. The remote units acquire seismic data from their associated receivers in response to a seismic shock wave induced at a selected point on the earth and transmit the acquired seismic data to a recorder over a separate channel associated with each receiver. A signature device located at a known receiver location transmits a data sequence containing an embedded time-invariant code that is unique to the signature device to the recorded during the recording cycle. The signature device data sequence and its location are pre-recorded in the recorder. The recorder utilizing the stored data sequence and the data sequence transmitted by the signature device during the recording cycle to map the seismic data channels corresponding to the locations of their associated receivers.

Abstract: Methods for processing sonic logging data obtained by a sonic imaging tool or an MWD tool are provided. The sonic logging data are bandpass filtered and sampled according to techniques such as integer band decimation, quadrature modulation, and single side band modulation to provide compressed signals which can be reconstructed if desired. The compressed signals are alternatively stored for downloading and further processing, sent uphole for processing, or processed downhole. The processing preferably involves processing the analytic portion of the compressed signals according to an improved semblance processing technique where the semblance function is calculated over a time window utilizing coarse slowness and time sampling steps. The slowness and time sampling steps are dictated by the parameters of the bandpass filter and the inter-receiver spacing of the tool. The waveform for each receiver is preferably interpolated based on the time step size to provide those data points necessary for stacking.

Abstract: A telemetry system employs a periodic pseudorandom training sequence to effectively initialize an adaptive digital FIR filter-equalizer for optimal communications between a surface modem and downhole measuring equipment, without requiring any changes to the normal logging configuration or any special operator intervention. In a "training mode", an electronic source in a downhole sonde transmits a predetermined training sequence to a surface modem via a cable. The source preferably transmits the training sequence continuously until the surface modem has acclimated itself to the characteristics of the multiconductor cable by adaptively configuring the filter-equalizer, thereby enabling the surface modem to accurately interpret data received from the sonde despite attenuation, noise, or other distortion on the cable. The filter-equalizer adjusts itself in response to an error signal generated by comparing the filter-equalizer's output with a similar training sequence provided by a training generator.

Abstract: The operation of hostile environment logging tools at temperatures up to 250.degree. C. stresses not only the tools, it also places severe demands upon the wireline telemetry due to the wide variations in the logging cable transmission characteristics. A robust adaptive wireline telemetry system for use in hostile environments has been developed that combines sophisticated digital communication methods with modern Digital-Signal-Processing (DSP) techniques. The downhole telemetry transmitter outputs a multilevel signal. The uphole receiver includes an adaptive transversal-filter equalizer (TFE) that is continually optimized to correct for changing signal distortion. The system operates robustly at high data rates over the temperature range of 0.degree. to 250.degree. C.

Abstract: A method for the automatic association, with seismic signals received by receivers (R1 . . . Rn) distributed on a site to be explored, of topographic data relative to the location of these receivers. The seismic signals are collected and stored by seismic acquisition devices (B1-Bn) which, after each seismic "shooting", transmit the signals successively to a central station 1. When the receivers are positioned in the field, each receiver is located by means of radiopositioning of the GPS type for example, and the position indications are introduced into an auxiliary memory of the corresponding acquisition device. After each repatriation of the data of a shooting, the indications are read in this memory and remain associated with those data at the time of the general grouping on the tape recorder of the central station.

Abstract: A seismic recording system comprises a multichannel recorder connected to a cable formed from a plurality of signal conductors. Each of the signal conductors is connected to a different channel of the recorder. The cable has a plurality of takeouts located at spaced distances along its length. Each of the takeouts is connected to a different signal conductor of the cable. The system further includes a switch operably connected to one of the takeouts for selectively interconnecting the takeout and any one or more of several seismic detector connections upon receipt of a remotely generated signal. The system also includes a number of detector conduits, each of which has one end operably connected to a different one of the seismic detector connections of the switch. Each detector conduit has at least one geophone located along its length and operably connected thereto. A control is provided for transmitting a signal to a switch. The switch interconnects a selected group or groups of geophones with the recorder.

Abstract: For use with marine seismic streamers, a two-wire, multi-channel communication system capable of handling the high throughput necessary for effective communication between a central controller aboard a tow vessel and the many sensors deployed along the streamer. The central controller includes an intelligent modem with the capability of transmitting and receiving frequency-modulated message signals on one or more signal lines, such as conventional twisted-pair wires, over a number of individual inbound and outbound frequency channels. In the preferred embodiment, seventeen channels are spread over a frequency band ranging from about 20 kHz to 100 kHz, thereby making available for communication a bandwidth much wider than available in conventional single-channel streamer communication.

Abstract: The short hop communication link includes a sensor module positioned downhole from a motor in a well. The module includes sensors that monitor operational, directional and environmental parameters downhole and provide an electrical data signal indicative thereof. Sensors may also be positioned in the drill bit for obtaining parameters related to the bit, and communicating data signals reflecting the sensed parameters to the sensor module. The sensor module includes a transceiver, with an annular anrenna, for transmitting electromagnetic sensor data signals to a point above the motor. A control module, which also includes a transceiver with an annular antenna, is located above the motor, and receives the electromagnetic signals from the sensor module reflecting the sensed parameters. In addition, the control module is capable of transmitting command signals to the sensor module requesting data regarding desired parameters.

Abstract: Transponders in or with a shallow water seismic cable emit acoustic signals for acoustic ranging on command from a transceiver aboard a seismic exploration vessel. The acoustic ranging data together with navigational data cna be used to identify cable location. The transponders are activated by individual identifying digital codes. Each such digital code is a data word of suitable length composed of a distinctive frequency sent in bursts for a specific time for successive pairs of bits, or di-bits, in the data word. The time spacing between sending the frequency bursts is also used to carry other di-bits of the data word.

Abstract: A seismic recording system comprises a multichannel recorder connected to a cable formed from a plurality of signal conductors. Each of the signal conductors is connected to a different channel of the recorder. The cable has a plurality of takeouts located at spaced distances along its length. Each of the takeouts is connected to a different signal conductor of the cable. The system further includes a first conduit operably connected to one of the takeouts. A plurality of remotely operable switch means are located along the length of the first conduit for selectively interconnecting the first conduit and a plurality of detector conduits upon receipt of a remotely generated signal. Each detector conduit has at least one geophone located along its length and operably connected thereto. A control means is provided for transmitting a signal to a selected switch means for interconnecting its associated detector conduit and geophones with the recorder.

Abstract: A buoyed sensor array communications system comprises multiple sensor syss electrically connected to a signal transmission line which are positioned at predetermined locations along the signal transmission line to form a linear sensor array. Each of the sensor systems generates a data signal in response to receiving an address signal. The system further includes; a processor system electrically connected to the signal transmission line for transmitting address signals to enable any one of the sensor systems at a time in a selectively accessed order and has a data storage memory for storing the data signal from each of the sensor systems as stored data. A radio frequency transmitting system is coupled to the data processor and transmits the stored data at a predetermined time. A negatively buoyant structure connected to the signal transmission line pulls the communications system to the bottom of a body of water upon deployment.