Abstract: A method and a downhole telemetry system a downhole telemetry system using discrete multitone modulation for transmitting a data stream over a plurality of transmission modes is provided. The downhole telemetry system includes a downhole transmitter, a cable, and a surface receiver. The downhole transmitter is configured to transmit the data stream over the plurality of transmission modes. The surface receiver is coupled to the downhole transmitter via the cable and is configured to combine signals from each of the plurality of transmission modes to obtain the data stream transmitted by the downhole receiver. The method includes receiving a plurality of signals over the plurality of transmission modes from a downhole package, and may further include combining the plurality of signals to form at least one data stream.

Abstract: A method for triggering an action of at least one downhole device on a downhole network integrated into a downhole tool string synchronized to an event comprises determining latency, sending a latency adjusted signal, and performing the action. The latency is determined between a control device and the at least one downhole device. The latency adjusted signal for triggering an action is sent to the downhole device. The action is performed downhole synchronized to the event. A preferred method for determining latency comprises the steps: a control device sends a first signal to the downhole device; after receiving the signal, the downhole device sends a response signal to the control device; and the control device analyzes the time from sending the signal to receiving the response signal.

Abstract: Methods of subsea communication in which a cathodic protection anode is used as a transmitting antenna. The signals are received at a second location by two electrodes which are spaced apart by different distances from the transmitting antenna.

Abstract: A signal transmission connection for a tool string used in exploration and production of natural resources, namely: oil, gas, and geothermal energy resources. The connection comprises first and second annular elements deployed in cooperative association with each other. The respective elements comprise inductive transducers that are capable of two-way signal transmission between each other, with downhole components of the tool string, and with ground-level equipment. The respective inductive transducers comprise one or more conductive loops housed within ferrite troughs, or within ferrite trough segments. When energized, the conductive loops produce a magnetic field suitable for transmitting the signal. The second element may be rotational in drilling applications. The respective elements may be fitted with electronic equipment to aid and manipulate the transmission of the signal. The first element may also be in communication with the World Wide Web.

Abstract: A method of managing oil fields include installing oil field sensors, coupling them to a local CPU having memory, programming the CPU for data collection and data analysis, and coupling local oil field CPUs to a web server. Human experts are granted access to oil field data in real time via the Internet. The local CPUs provide different levels of data to the web server. The web server provides the option to view raw data, partially analyzed data, or fully analyzed data. The local CPUs are programmed with parameters for analyzing the data and automatically determining the presence of anomalies. Upon detecting the occurrence of an anomaly, the local CPUs are programmed to notify one or more human experts by email, pager, telephone, etc. If no human expert responds to the notification within a programmed period of time, the local CPU automatically takes a programmed corrective action.

Abstract: A logging tool includes a tool body; a simple transmitter comprising a single antenna disposed on the tool body; four simple receivers, each comprising a single antenna, disposed on the tool body and spaced apart from the simple transmitter to form four arrays; and an electronic module for controlling operation of the four arrays, wherein the simple transmitter is configured to generate a magnetic field having a transverse component, wherein each of the four simple receivers is sensitive to the magnetic field generated by the simple transmitter, and at least one of the four simple receivers is sensitive to the transverse component of the magnetic field generated by the simple transmitter, and wherein the four arrays are configured to provide measurements at at least three depths of investigation.

Abstract: A downhole telemetry system having a surface transceiver, a cable, and a downhole transceiver coupled to the surface transceiver via the cable. The surface transceiver isolates an uplink signal from a combined uplink/downlink signal on the cable using time-domain signal cancellation. The downhole transceiver isolates a downlink signal from the combined uplink/downlink signal using time-domain signal cancellation. In the surface transceiver, the time-domain signal cancellation may be performed by running the combined uplink/downlink signal through a coil of a transformer while running a copy of the downlink signal through an opposite coil of the transformer. Likewise, in the downhole transceiver, the time-domain signal cancellation may be performed by running the combined uplink/signal through a coil of a transformer while running a copy of the uplink signal through an opposite coil of the transformer.

Abstract: A method and related apparatus for telemetry between downhole devices and surface devices. In particular, the methods and related apparatus may send a first datum of a first parameter in an uncompressed form, and send a second datum of the first parameter in compressed form.

Abstract: A system for transmitting data through a string of downhole components. In one aspect, the system includes first and second magnetically conductive, electrically insulating elements at both ends of the component. Each element includes a first U-shaped trough with a bottom, first and second sides and an opening between the two sides. Electrically conducting coils are located in each trough. An electrical conductor connects the coils in each component. In operation, a varying current applied to a first coil in one component generates a varying magnetic field in the first magnetically conductive, electrically insulating element, which varying magnetic field is conducted to and thereby produces a varying magnetic field in the second magnetically conductive, electrically insulating element of a connected component, which magnetic field thereby generates a varying electrical current in the second coil in the connected component.

Abstract: Methods and systems for borehole telemetry are disclosed. In one embodiment, a borehole telemetry system includes a coiled tubing string that is located in the borehole. A receiver is coupled to the coiled tubing string. In one possible implementation, the receiver is located inside the coiled tubing string. A transmitter is also coupled to the coiled tubing string. The transmitter generates signals guided for at least a portion of their path by the entire internal cross-section of the coiled tubing string to the receiver.

Abstract: A system and method for remote asset management is described which can provide the basis for a diverse product group including an improved remote location monitoring system, a means for communicating with and for monitoring the status and or location of a plurality of diverse assets, as well as the means for communicating with said assets for the purpose of modifying the operational status of one or more of said assets according to one or more stored data parameters such as location, use, battery power, and such like. The remote asset management system comprises a wireless module, which is associated with at least one of the plurality of asset and which is interfaced with the operating system of said assert and or with an electromechanical control means, which may control one or more features of the operation of said assets.

Abstract: A well servicing system includes a computer-based system that monitors pumping or other service operations at a well site and monitors deliveries and withdrawals of chemicals at a bulk storage station. A GPS device or other location identifier provides a location value that identifies the location of the service vehicle. A GPS reading is triggered by actuation of the vehicle's parking brake, and the location value is recorded in association with a process-related transducer value. The transducer value is based on the service vehicle performing some type of service operation either at the well site or at the bulk storage station.

Abstract: A method and apparatus is disclosed for transmitting digital signals across safety transmission barrier. High data transfer rates are achieved for transfer from a safe certified device across the transmission barrier to a standard or non-rated device. A signal pair is generated including a first digital signal from the safe device and a second digital signal that is phase shifted from the first digital signal. Preferably, the second signal is phase shifted by 180 degrees, essentially being an inverted version of the first digital signal. The first and second digital signals are transmitted across the transmission barrier to a receiver in a safe area. An output signal is then reconstructed based on the falling edges of the first and second digital signals. The reconstructed signal closely approximates the first digital signal.

Abstract: A system and method are disclosed that provide for transmitting data from a downhole location to the surface. In one embodiment, a communications medium provides data transfer capabilities to the surface. A first downhole instrument is associated with the communications medium in order to measure a first downhole parameter and transmit first data relative to the first downhole parameter to the surface via the communications medium at a first time. A second downhole instrument is associated with the communications medium in order to measure a second downhole parameter and transmit second data relative to the second downhole parameter to the surface via the communications medium at a second time such that the first data is interleaved with the second data.

Abstract: The specification discloses algorithms for error recovery in pulse position modulation-based mud pulse telemetry. More particularly, the specification discloses detection and attempted correction of at least five possible error mechanisms: the missed detection of a pulse that creates an interval greater than maximum; the missed detection of a pulse that results in an interval still within acceptable boundaries; detection of an extra pulse; a pulse shift that results in data in contiguous intervals being affected; and a pulse shift resulting in a single interval data corruption.

Abstract: A system for automatic collection and transport of readings from water, gas and electricity meters wherein at least one receiver element and one element to transmit (1) define an ad-hoc wireless network, self organizing in an area (A), where the readings are transmitted to the next element using multihop techniques according to a routing algorithm. A value t is assigned to the receiver elements (1), with maximum value T. If the direct neighbours of a given network node have as a maximum an assigned value t, a value t-k is assigned to this node. Every node will transmit a message to a node with t value larger than its own. If there is more than one with the same maximum value, it will transmit to one of them. The system allows the meter reading to be transported automatically to the billing center.

Abstract: It is an object of the invention to measure a communication data volume for each service type in measuring a communication data volume in a charging process and the like. The invention comprises a plurality of measuring points 131 to 133 for measuring a communication data volume and a data relaying apparatus 120 for transmitting received data to any of the plurality of measuring points 131 to 133. The data relaying apparatus 120 has a service-type judging means 121 for judging the service type of the received data, a measuring point determining means 122 for determining the measuring points 131 to 133 to which the data is to be transmitted based on the service type and a data transmission means 122 for transmitting the data to the measuring point thus determined, and each of the plurality of measuring points 131 to 133 has a communication data measuring means for measuring the communication data volume of the data received from the data relaying apparatus 120.

Abstract: An apparatus and a method for controlling oilfield production to improve efficiency includes a remote sensing unit that is placed within a subsurface formation, an antenna structure for transmitting power and communicating signals to the remote sensing unit and for receiving communication signals from the remote sensor, a casing joint having nonconductive “windows” for allowing an internally located antenna to communicate with the remote sensing unit for those embodiments in which a wireline tool is being used to communicate with remote sensing unit, and a system for obtaining subsurface formation data and for producing the formation data to a central location for subsequent analysis. The remote sensing unit is a standalone sensor that is placed sufficiently far from the wellbore to reduce or eliminate effects that the wellbore might have on formation data samples taken by the remote sensing unit.

Abstract: A downlink telemetry system providing improved apparatus and methods for communicating instructions via pressure pulses from surface equipment to a downhole assembly. The apparatus comprises a surface transmitter for generating pressure pulses, a control system, and a downhole receiver for receiving and decoding pulses. In operation, a bypass valve is opened and closed to create a series of pressure pulses received and decoded by a downhole receiver. The method significantly reduces the time required for downlink communication without interrupting drilling and without interrupting uplink communications such that simultaneous, bi-directional communication is achievable if the uplink and downlink signals are sent at different frequencies. The telemetry scheme and algorithm provide an inventive method for filtering and decoding the downlink signals. The algorithm determines the time intervals between pulse peaks and decodes the intervals into an instruction.

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: Data is transmitted along a borehole containing a drill stem (2) by means of a transmitter (6) which converts electric data signals to acoustic signals propagating along the drill stem (2). The acoustic signals are converted back to electric form by a receiver (12) which also processes the signals. In the preferred form the signals are stored in a receiver memory (15) for subsequent retrieval using a pick-up tool (5) lowered into the borehole. The system is particularly useful in moving data past an obstruction such as a shut-in valve (4).

Abstract: A reprogrammable data communications system for use in a gas or oil well borehole is disclosed. The borehole includes a casing and a piping structure therein and at least one downhole equipment module located therein. The system provides for data and control signals to be coupled to the casing and piping structure by a surface modem and transmitted to the downhole equipment located in the downhole equipment modules. The downhole equipment modules include a downhole modem that is coupled to the casing and piping structure and receives the transmitted data and command signals and recovers the transmitted data and commands therefrom. A downhole processor is coupled to the downhole modem and receives the data and commands from the downhole modem and stores the data and commands in retentive memory that is coupled to the downhole processor. In this way, the downhole processor can be reprogrammed with new algorithms and communications parameters.

Abstract: The invention provides apparatus and methods for monitoring and controlling hydrocarbon production wells and/or injection wells from a remote location. The apparatus for monitoring and controlling one or more hydrocarbon production wells or injection wells from a remote location comprises one or more surface control and data acquisition systems; one or more sensors disposed in communication with the one or more control and data acquisition systems; one or more downhole flow control devices disposed in communication with the one or more control and data acquisition systems; and one or more remote controllers disposed in communication with the one or more control and data acquisition systems. Preferably, the remote controller comprises a computer having an internet access disposed in communication with the one or more control and data acquisition systems through a communication device comprising an internet web site server.

Abstract: An oscillating valve driven by the pressure in a mud pulser develops a pressure variation in the mud pulse signal that is at a frequency that is different than the frequencies of the mud system. The oscillating valve is coupled to or integral with the pulse drive cylinder, whether the drive means for operation of the pulser is upstream or downstream from the orifice, or whether or not the drive means and the poppet are on the same side or opposite sides of the orifice. The oscillating valve is a bistable valve which preferably forms one wall of the drive piston of the pulser. Pressure from the drive cylinder behind the drive piston is directed in such a way as to unseat the bistable valve. When the bistable valve unseats, pressure is bled from within the drive cylinder, which also bleeds the pressure that unseated the bistable valve in the first place.

Abstract: An apparatus and a method for controlling oilfield production to improve efficiency includes a remote sensing unit that is placed within a subsurface formation, an antenna structure for communicating with the remote sensing unit, a casing joint having nonconductive “windows” for allowing a internally located antenna to communicate with the remote sensing unit, and a system for obtaining subsurface formation data and for producing the formation data to a central location for subsequent analysis. The remote sensing unit is placed sufficiently far from the wellbore to reduce or eliminate effects that the wellbore might have on formation data samples taken by the remote sensing unit. The remote sensing unit is an active device with the capability of responding to control commands by determining certain subsurface formation characteristics such as pressure or temperature, and transmitting corresponding data values to a wellbore tool.

Abstract: An in-vehicle device data communicates with Internet based data processing resources for the purpose of transacting e-mail, e-commerce, and e-business. The in-vehicle device and the Internet based data processing resources can effectuate a wide variety of e-mail, e-commerce, and e-business including accessing auto part databases, warranty, customer, and other remote databases. In addition, e-mail, e-commerce, and e-business transactions can include vehicle security and vehicle service management, data communicating Internet based radio, audio, MP3, MPEG, video, and other types of data. Furthermore, e-mail, e-commerce, and e-business transactions can include interactive advertising, promotional offers, coupons, and supporting other remote data communications. The in-vehicle device can also include functionality for remote monitoring of vehicle performance, data communicating and accessing remote Internet based content and data, and effectuating adjustments and control of vehicle operation.

Abstract: For collecting data from a water well, down-hole sensors are housed in modules. The modules are arranged to be screwed together in-line to form a vertical string. Mechanically, the modules are secured to each other only by the screw connection. Data is transmitted to the surface on a 2-wire cable, there being no other electrical connection between the modules and the surface. The modules are connected in multi-drop configuration to the 2-wire cable. Data is transmitted using time-division multiplexing.

Abstract: An integrated, single collar measurement while-while-drilling tool is presented that comprises formation sensors, directional sensors, pressure sensors, a mud pulse telemetry device, and a turbine-generator power device configured in a single collar housing that is no longer than a standard drill collar. No electrical connections are made across drill collar tool joints. The tool provides high reliability and ease of transportation.

Abstract: An artificial neural network, ANN, and method of training the ANN for inversion of logging tool signals into well logs of formation parameters is disclosed. Properly selected synthetic models of earth formations are used to train the ANN. The models include Oklahoma and chirp type of formations. In each model parameter contrasts of from 10 to 1 to about 100 to 1 are included. Models including maximum and minimum parameter values spanning the operating range of the selected logging tool are included. Parameter contrasts at interfaces are limited to realistic values found in earth formations. The selected models are used to generate synthetic tool signals, which are then used as inputs to the ANN for training. When the ANN coefficients are properly adjusted to produce an output matching the original models, the ANN can be used for inversion of any real signals from the selected logging tool.

Abstract: A synchronous CDMA telemetry system is provided for use in a wellbore. In one described embodiment, each data bit of digital outputs of multiple downhole data sources is multiplied by an orthogonal code unique to each data source. The resulting encoded outputs are modulated on a carrier frequency and summed on a transmission channel. The resulting signal is demodulated at a remote location and separately multiplied by each of the codes to separate out the contributions to the signal from each data source. The individual demodulated and decoded outputs are then integrated over the length of each data bit.

Abstract: Apparatus and methods for webserver-based well instrumentation, logging, monitoring and control provide convenience and economy in well site and off-site operations. In a described embodiment, a well tool includes a webserver connected to a sensor and an actuator of the tool. In response to a condition sensed by the sensor, a person utilizing a network to access a web page supported by the webserver at a remote location may operate the actuator to control operation of the well tool.

Abstract: A method for two-way communication for controlling production from a formation having at least one producing well and a plurality of producing zones. In one embodiment, the method comprises installing a flow control device with a controller proximate each of the producing zones, where each controller has a predetermined communication address, and each controller is adapted to act as a repeater on command from a surface controller; connecting each controller to a transmission bus where the transmission bus is connected to the surface controller; transmitting a command message from the surface controller to a predetermined downhole controller, where the command message determines a predetermined path along the transmission bus according to a predetermined protocol; receiving the command message by the predetermined controller; and executing the command message to control the flow control device. Transmitting a response message back along the predetermined path.

Abstract: A method and apparatus for a computer controlled apparatus for use in wellbore completions. A touch-screen is provided that facilitates commands and information that is entered by an operator ordering movement of a downhole tool. In another embodiment, real-time information about the status of the downhole tools is transmitted to the apparatus based upon operating variables within the system, like pressure, flow rate, total flow, and time.

Abstract: An electromagnetic borehole telemetry system providing improved signal to noise ratio. Adaptive filters use noise channels as references to remove noise from the signal channel. Improved sensors provide noise channels with reduced signal content. Motion sensors are used to detect noise and provide a noise channel free of signal content. The motion sensors are shielded from electromagnetic signals to prevent detection of the telemetry signal.

Abstract: A method and apparatus is disclosed for transmitting digital signals across safety transmission barrier. High data transfer rates are achieved for transfer from a safe certified device across the transmission barrier to a standard or non-rated device. A signal pair is generated including a first digital signal from the safe device and a second digital signal that is phase shifted from the first digital signal. Preferably, the second signal is phase shifted by 180 degrees, essentially being an inverted version of the first digital signal. The first and second digital signals are transmitted across the transmission barrier to a receiver in a safe area. An output signal is then reconstructed based on the falling edges of the first and second digital signals. The reconstructed signal closely approximates the first digital signal.

Abstract: An induction choke in a petroleum well where a voltage potential is developed across the choke to power and communicate with devices and sensors in the well. Preferably, the induction choke is a ferromagnetic material and acts as an impedance to a time-varying current, e.g. AC. The petroleum well includes a cased wellbore having a tubing string positioned within and longitudinally extending within the casing. A controllable gas lift valve, sensor, or other device is coupled to the tubing. The valve sensor, or other device is powered and controlled from the surface. Communication signals and power are sent from the surface using the tubing, casing, or liner as the conductor with a casing or earth ground. For example, AC current is directed down a casing or tubing or a lateral where the current encounters a choke. The voltage potential developed across the choke is used to power electronic devices and sensors near the choke.

Abstract: The present invention includes an apparatus and method for telemetry communication with oil-well monitoring and recording instruments located in the vicinity of the bottom of gas or oil recovery pipes. Such instruments are currently monitored using electrical cabling that is inserted into the pipes; cabling has a short life in this environment, and requires periodic replacement with the concomitant, costly shutdown of the well. Modulated reflectance, a wireless communication method that does not require signal transmission power from the telemetry package will provide a long-lived and reliable way to monitor down-hole conditions. Normal wireless technology is not practical since batteries and capacitors have to frequently be replaced or recharged, again with the well being removed from service. RF energy generated above ground can also be received, converted and stored down-hole without the use of wires, for actuating down-hole valves, as one example.

Abstract: A system and method in accordance with the invention communicator remotely with remotely controllable down hole tools in a well bore at a drilling installation. At the surface, high energy pressure impulses directed into the tubing or the annulus, or both, being at a level to propagate through an interface between very different impedances zones, such as an upper level gas zone and a lower level of mobile fluid media extending down into the desired downhole location. The pressure impulses, provided by directionally gating along the longitudinal confining path a pressure impulse initially having sharp leading and trailing edges, reach the downhole location as physical perturbations forming a discernible pattern that can be detected by one or more energy responsive transducers. With combinations of these signals, one of a number of separate control devices can be remotely actuated.

Abstract: A system and method for communicating information between downhole equipment in a wellbore and surface equipment, comprising a first device disposed in a wellbore for receiving at least one first signal and transmitting at least one second signal. A surface device is used for receiving the at least one second signal and transmitting the at least one first signal. At least one repeater is disposed at a predetermined location in a wall of the wellbore for receiving and retransmitting the first signal and the second signal. A method for communicating information between downhole equipment in a wellbore and surface equipment, comprises deploying a tubular member in the wellbore, the tubular member having a transmitter disposed therein; disposing at least one signal repeater at a predetermined location in a wall of the wellbore; and transmitting a signal from the transmitter to a surface receiver through the at least one repeater.

Abstract: The invention is directed to a device for the generation of pressure pulses, being intended for transmitting signals, in a fluid-carrying channel (2), using a pulser (1) designed to be integrated in the channel (2) and having a housing (4) and an adjustable throttling device by means of which the flow resistance can be varied at at least one point of the channel (2), an electrical generator (16), an impeller (9) exposed to the fluid passing through the channel and designed to drive the generator (16), a control device by means of which the load of the generator (16) can be varied in response to control signals, and an actuating device that is connected to the throttling element (12) and effects an adjustment of the throttling element responsively to the driving torque of the generator (16).

Abstract: An antenna assembly for an induction logging tool for use in a drilling operation. The assembly includes an outer pressure housing, a coil former within the pressure housing, magnetic cores mounted in the housing, a core carrier within the coil former and the pressure housing which carries the magnetic cores, and shock-absorbing mountings on the core carrier for the magnetic cores.

Abstract: Methods and apparatus for communicating between a MWD or LWD logging tool and a surface processor, such as a PC, using a high speed transmission control protocol-internet protocol (TCP-IP) based connection link. Logging tool sensor response is stored in memory within the tool while logging. The link is removably attached to a data port in the tool when the tool is subsequently removed from the borehole. Stored sensor response information is transferred very rapidly from tool memory as TCP-IP data packets. Transmission is two-way thereby allowing commands to be transmitted from the PC to the tool for control of the tool and the data acquisition function of the tool. The two-way data transmission function can be performed at one or more PC's remote from a drilling rig using a commercially available TCP-IP hub and the internet.

Abstract: A system for delivering medical fluid to a patient includes a medical container including a Radio Frequency Identification (RFID) tag storing data related to the medical fluid therein. A RF reader receives data signals transmitted from the RFID tag that include a desired flow rate for delivering the fluid to the intended patient. A pump coupled to the reader includes a pumping mechanism for pumping the medical fluid from the container, and a pump controller for receiving the data including the desired flow rate from the reader. The pump controller automatically controls the pumping mechanism to pump the medical fluid from the medical container at the desired flow rate based upon the data.

Abstract: An apparatus and a method for controlling oilfield production to improve efficiency includes a remote sensing unit that is placed within a subsurface formation, an antenna structure for transmitting power and communicating signals to the remote sensing unit and for receiving communication signals from the remote sensor, a casing joint having nonconductive “windows” for allowing an internally located antenna to communicate with the remote sensing unit for those embodiments in which a wireline tool is being used to communicate with remote sensing unit, and a system for obtaining subsurface formation data and for producing the formation data to a central location for subsequent analysis. The remote sensing unit is a standalone sensor that is placed sufficiently far from the wellbore to reduce or eliminate effects that the wellbore might have on formation data samples taken by the remote sensing unit. The subsurface formation data values are transmitted to a central location for analysis.

Abstract: An interactive (‘InterACT’) apparatus and associated method will transmit wellbore information, in real time, to a client approximately simultaneously with a generation of the wellbore information at a well site, in response to interactive requests made by the client at a workstation computer over the internet, without requiring the client to actually travel to the well site in order to acquire and view the wellbore information. In addition, the interactive apparatus and associated method will generate and display, on a client's display screen of the client's personal computer or workstation, a unique ‘display window’ (known as the ‘InterACT Stimulation Viewer’) when the client is accessing the internet using only the client's ‘browser’ software that is already installed on the client's personal computer (such as, Netscape Navigator or Microsoft Internet Explorer).

Abstract: In order to ensure that at least some of the tools (12-1) to 12-4) in a string of tools that is permanently installed in an oil well (10) are kept in operation even in the event of a localized fault, the link (18) interconnecting the tools and a surface installation (16) is subdivided into segments by switch members (20). More precisely, a switch member is associated with each tool. In addition, the link (18) forms a loop with both ends thereof being connected to the surface installation (16).

Abstract: An acoustic MWD system comprises at least one transmitter array and at least one receiver array spaced axially along an essentially tubular downhole subassembly. Each transmitter and receiver array includes a plurality of elements circumferentially disposed on the outside of the assembly. The downhole subassembly also comprises a processor, data storage, telemetry elements, power supplies and control circuits as well as other types of sensors. In one embodiment of the invention, the transmitters are operated as a quadrupole in orthogonal orientations and signals from two receiver elements processed to attenuate common modes (including body waves through the tool, monopole waves and Stoneley waves). In another embodiment, the transmitters are used as crossed dipoles and signals received by cross-dipole receivers may be used to determine shear wave birefringence in the formation.

Abstract: Various means of identifying individual joints of drill pipe or other drill tools have been suggested but have found only narrow utility. Such means include low frequency radio frequency identification systems that are inherently limited by short read ranges and require the reader antenna be placed directly over and very close to an embedded identification tag. With the development of mid-frequency and high frequency systems for radio frequency identification, read distances become much longer and a Gigahertz identification tag has recently been specifically developed for automatic drill string component identification. This invention provides a means for configuring, assembling and providing in-hole protection to a Gigahertz or other radio frequency identification tags.

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.

Abstract: An apparatus for sending signals downhole during drilling operations uses a main pump to pump mud from a mud pit at a substantially constant flow rate. The bulk of the pumped mud goes downhole to maintain adequate circulation for the drill bit. A bypass pipe is provided with a shut-off valve that is controlled by an electronic controller. By pulsing the opening and closing of the shut-off valve, the volumetric flow downhole is pulsed. The pulse amplitude and duration can be controlled. These pulses in the flow rate are detected by a suitable downhole device such as a flow rate measurement device, a pressure detector or a turbine. The initial “wake-up” pulse is made long enough so that the detection device downhole is always able to detect it. Subsequent to this wake-up pulse, adjustments are made to the pulse duration, in steps of about 2 seconds, for the smallest pulse period that is detectable downhole.