Antenna for downhole communication using surface waves

An assembly can include a casing string with an outer surface. The assembly can also include an antenna for wirelessly communicating data by generating a surface wave that propagates along an interface surface. The antenna can be positioned coaxially around the casing string. The antenna can include a cylindrically shaped conductor that is positionable coaxially around an outer surface of a casing string for generating a magnetic field component of the surface wave that is non-transverse to a direction of propagation of the surface wave along the interface surface. The antenna can also include a pair of conductive plates positioned at an angle to the cylindrically shaped conductor for generating an electric field component of the surface wave.

ANTENNA FOR DOWNHOLE COMMUNICATION USING SURFACE WAVES

An assembly can include a casing string with an outer surface. The assembly can also include an antenna for wirelessly communicating data by generating a surface wave that propagates along an interface surface. The antenna can be positioned coaxially around the casing string. The antenna can include a cylindrically shaped conductor that is positionable coaxially around an outer surface of a casing string for generating a magnetic field component of the surface wave that is non-transverse to a direction of propagation of the surface wave along the interface surface. The antenna can also include a pair of conductive plates positioned at an angle to the cylindrically shaped conductor for generating an electric field component of the surface wave. 1. An assembly comprising:a casing string with an outer surface; and a cylindrically shaped conductor that is positionable coaxially around the outer surface of the casing string for generating a magnetic field component of the surface wave that is non-transverse to a direction of propagation of the surface wave along the interface surface; and', 'a pair of conductive plates positioned at an angle to the cylindrically shaped conductor for generating an electric field component of the surface wave., 'an antenna for wirelessly communicating data by generating a surface wave that propagates along an interface surface, the antenna positioned coaxially around the casing string and comprising2. The assembly of claim 1 , wherein the antenna is operable to generate the electric field component such that the electric field component is non-transverse to the direction of propagation of the surface wave along the interface surface.3. The assembly of claim 2 , wherein the interface surface is between the casing string and a cement sheath.4. The assembly of claim 1 , wherein the angle is 0 degrees or 90 degrees.5. The assembly of claim 1 , wherein the antenna is operable to generate the surface wave responsive to receiving a signal with a ...

Methods and apparatus for evaluating downhole conditions with RFID MEMS sensors

A radio frequency identification (RFID) tag can include a die attached to an inductive-capacitive (LC) circuit including a capacitive element coupled to an inductive element. The LC circuit can have a resonant frequency that varies according to properties of fluid proximate the RFID tag. The RFID tag can further include a coating material disposed around the die to form an outer surface of the RFID tag. The coating material may have a thickness over a portion of the LC circuit, to permit a conductivity property of a fluid proximate the outer surface to affect the resonant frequency of the LC circuit such that the resonant frequency shifts to a second resonant frequency. Additional apparatus, systems, and methods are disclosed.

Methods and apparatus for evaluating downhole conditions through fluid sensing

An apparatus and method may operate to mount one or more communication assemblies relative to the exterior of a casing being placed in a borehole. Two communication assemblies can be placed in longitudinally spaced relation to one another along the casing, wherein each communication assembly is configured to obtain excitation responses from electrodes of a fluid sensing component, where the excitation responses vary based on properties of fluids in one or more regions of the annulus surrounding the casing. Additional apparatus, systems, and methods are disclosed.

Downhole Fluid Detection Using Surface Waves

A communication system that is positionable in a wellbore can include a first transceiver positioned externally to a casing string. The first transceiver can be operable to detect a presence or an absence of a surface wave; determine a location of a fluid in the wellbore based on the presence or the absence of the surface wave; and transmit data indicative of the location to a second transceiver. The surface wave can include an electromagnetic wave that has a magnetic field or an electric field that is non-transverse to a direction of propagation of the surface wave. The communication system can also include the second transceiver, which can be positioned externally the casing string and operable to receive the data. 1. A communication system that is positionable in a wellbore , the communication system comprising:a first transceiver positioned externally to a casing string and operable to detect a presence or an absence of a surface wave, determine a location of a fluid in the wellbore based on the presence or the absence of the surface wave, and transmit data indicative of the location to a second transceiver, wherein the surface wave comprises an electromagnetic wave that includes a magnetic field or an electric field that is non-transverse to a direction of propagation of the surface wave; andthe second transceiver positioned externally the casing string and operable to receive the data.2. The communication system of claim 1 , wherein the first transceiver is electrically coupled to a sensor comprising a pressure sensor claim 1 , a temperature sensor claim 1 , a microphone claim 1 , a resistivity sensor claim 1 , a vibration sensor claim 1 , or a fluid flow sensor for determining a characteristic of the fluid claim 1 , the casing string claim 1 , or a cement sheath.3. The communication system of claim 2 , wherein the first transceiver comprises:a processing device; and receive a sensor signal from the sensor;', 'determine a property of the wellbore or the fluid ...

Downhole Communications Using Frequency Guard Bands

A system that is positionable in a wellbore can include a chain of transceivers that are positionable external to a casing string. Each transceiver in the chain of transceivers can be operable to transmit a wireless signal using a separate frequency guard band that is assigned to that transceiver and to receive wireless signals using another frequency guard band assigned to a prior transceiver in the chain of transceivers. 1. A system that is positionable in a wellbore , the system comprising:a chain of transceivers that are positionable external to a casing string, each transceiver in the chain of transceivers being operable to transmit a wireless signal using a separate frequency guard band assigned to that transceiver and to receive wireless signals using another frequency guard band assigned to a prior transceiver in the chain of transceivers.2. The system of claim 1 , wherein the frequency guard band comprises an unused range of frequencies that is between adjacent frequency bands for separating the adjacent frequency bands.3. The system of claim 1 , wherein each transceiver in the chain of transceivers is operable to receive a control signal from a remote device and select the separate frequency guard band based on the control signal.4. The system of claim 3 , wherein each transceiver in the chain of transceivers is remotely programmable subsequent to the transceiver being positioned in the wellbore.5. The system of claim 1 , wherein each transceiver in the chain of transceivers comprises:a processing device; and receive a control signal; and', 'select the frequency guard band and a particular frequency within the frequency guard band based on the control signal by consulting a lookup table stored in the memory device in which the frequency guard band and a plurality of frequencies within the frequency guard band are mapped to a plurality of characteristics of the control signal., 'a memory device in which instructions executable by the processing device are ...

Downhole Wireless Communications Using Surface Waves

A communication system that is positionable in a wellbore can include a first transceiver for coupling externally to a casing string. The first transceiver can be for wirelessly transmitting data by generating and modulating a surface wave that propagates along an interface surface. The surface wave can include an electromagnetic wave that has a magnetic field or an electric field that is at an acute angle to a direction of propagation of the surface wave. The communication system can also include a second transceiver for coupling to the casing string and for wirelessly receiving the surface wave and detecting the data. 1. A communication system that is positionable in a wellbore , the communication system comprising:a first transceiver for coupling externally to a casing string and for wirelessly transmitting data by generating and modulating a surface wave that propagates along an interface surface, wherein the surface wave comprises an electromagnetic wave that includes a magnetic field or an electric field that is at an acute angle to a direction of propagation of the surface wave; anda second transceiver for coupling to the casing string and for wirelessly receiving the surface wave and detecting the data.2. The communication system of claim 1 , wherein the interface surface is between the casing string and a cement sheath.3. The communication system of claim 1 , wherein the first transceiver is electrically coupled to a sensor comprising a pressure sensor claim 1 , a temperature sensor claim 1 , a microphone claim 1 , a resistivity sensor claim 1 , a vibration sensor claim 1 , or a fluid flow sensor for receiving a sensor signal from the sensor and modulating the surface wave based on the sensor signal.4. The communication system of claim 3 , wherein the first transceiver comprises:a processing device; and receive the sensor signal from the sensor;', 'generate a transmission signal based on the sensor signal; and', 'transmit the transmission signal to an ...

Downhole Communications Using Selectable Frequency Bands

A system that is positionable in a wellbore in a subterranean formation can include a first transceiver that is positionable external to a casing string in the wellbore. The first transceiver can wirelessly transmit data via a signal within a frequency band that is selected based on a fluid property of a fluid in the wellbore and a property of the subterranean formation. The system can also include a second transceiver that is positionable externally 1. A system that is positionable in a wellbore in a subterranean formation , the system comprising:a first transceiver that is positionable external to a casing string in the wellbore for wirelessly transmitting data via a signal within a frequency band that is selected based on a fluid property of a fluid in the wellbore and a property of the subterranean formation; anda second transceiver that is positionable externally the casing string and operable to receive the signal.2. The system of claim 1 , wherein the first transceiver is operable to transmit the data via the signal and via another signal within another frequency band substantially simultaneously.3. The system of claim 1 , wherein the fluid comprises a combination of a wellbore servicing fluid and a formation fluid.4. The system of claim 1 , wherein the first transceiver comprises:a processing device; and receive a sensor signal from a sensor;', 'determine the fluid property based on the sensor signal;', 'determine the property of the subterranean formation based on the sensor signal; and', 'select the frequency band based on the fluid property and the property of the subterranean formation by consulting a lookup table stored in the memory device in which a plurality of fluid properties and a plurality of subterranean formation properties are mapped to a plurality of frequency bands., 'a memory device in which instructions executable by the processing device are stored for causing the processing device to5. The system of claim 1 , wherein the first ...

DYNAMIC SENSING OF THE TOP OF CEMENT (TOC) DURING CEMENTING OF A WELL CASING IN A WELL BORE

A well casing is cemented in a well bore in a subterranean formation by pumping cement slurry down into the well casing so that the cement slurry flows up into an annulus surrounding the well casing. While pumping the cement slurry, the position of the top of the cement slurry in the annulus is sensed, and the rise of the sensed position of the top of the cement slurry in the annulus is recorded as a function of time. The recording is analyzed to evaluate the cement job. For example, the analysis may indicate a problem addressed by adjusting a cement plan for a future cement job, and the analysis may indicate a need to repair a location of the set cement by perforating the well casing at the location to be repaired, and pumping cement slurry down the well casing to fill the location to be repaired. 1. A method of cementing a well casing in a well bore in a subterranean formation , said method comprising:(a) pumping cement slurry down into the well casing so that the cement slurry flows up into an annulus around the well casing in the well bore, and while pumping the cement slurry down into the well bore, sensing position of a top of the cement slurry in the annulus and recording a rise of the sensed position of the top of the cement slurry in the annulus as a function of time; and(b) analyzing the recording of the rise in the sensed position of the top of the cement slurry in the annulus as a function of time to evaluate the cementing of the well casing in the well bore.2. The method as claimed in claim 1 , wherein the analyzing of the recording of the rise in the sensed position of the top of the cement slurry in the annulus as a function of time indicates a problem claim 1 , and the method further includes adjusting a cement plan for a future cement job in view of the problem.3. The method as claimed in claim 1 , wherein the analyzing of the recording of the rise in the sensed position of the top of the cement slurry in the annulus as a function of time indicates ...

REPEATER FOR A WELLBORE

A repeater system provided in a wellbore including a plurality of communication units spaced at intervals along a length of a wellbore, the communication units being communicatively coupled via a transmission medium. The communication units are configured to relay data from one communication unit to another communication unit selected from the plurality of communication units along the transmission medium, wherein at least one of the communication units is hopped over as data is relayed across the plurality of communication units along the length of the wellbore. 1. A repeater system provided in a wellbore , the repeater system comprising:a plurality of communication units spaced at intervals along a length of a wellbore, the communication units being communicatively coupled via a transmission medium;the communication units being configured to relay data from one communication unit to another communication unit selected from the plurality of communication units along the transmission medium, wherein at least one of the communication units is hopped over as data is relayed across the plurality of communication units along the length of the wellbore.2. The repeater system of claim 1 , wherein the plurality of communication units are spaced at intervals along a length of a casing positioned within the wellbore.3. The repeater system of claim 1 , further comprising a master station located within the wellbore and coupled to at least one of the plurality of communication units claim 1 , the master station configured to transmit the relayed data to a receiving unit positioned outside an entrance hole of the wellbore.4. The repeater system of claim 3 , further comprising a network formed from the plurality of communication units claim 3 , the network relaying data from a first location in the wellbore to the master station claim 3 , the master station configured to transmit to a station unit positioned outside an entrance hole of the wellbore.5. The repeater system of ...

CASING COUPLING HAVING COMMUNCATION UNIT FOR EVALUATING DOWNHOLE CONDITIONS

A communication unit is situated in or on a casing collar. The casing collar has two threaded ends for joining casing joints to construct a well casing, and a communication unit is disposed in or on a central region of the tube between the two threaded ends. In an example, the communication unit has a transmitter for transmitting sensor data uphole from a sensor sensing a well bore condition. For example, the communication unit has a receiver for receiving sensor data from Micro-Electro-Mechanical Systems (MEMS) sensors, a transceiver for interrogating RFID tags, an acoustic transceiver for sensing wellbore conditions, a pressure sensor, a temperature sensor, and batteries for powering the communication unit. 1. Apparatus comprising:(a) a casing collar having two threaded ends for coupling two casing joints together; and(b) a communication unit situated on or in a central region of the casing collar, wherein the central region is located between the two threaded ends.2. The apparatus as claimed in claim 1 , wherein the casing collar has an outer cylindrical surface claim 1 , and the communication unit does not protrude from the outer cylindrical surface.3. The apparatus as claimed in claim 1 , wherein the casing collar has an outer cylindrical surface claim 1 , and the communication unit is situated in an annular groove in the outer cylindrical surface.4. The apparatus as claimed in claim 3 , further comprising the two casing joints coupled together by the casing collar claim 3 , wherein the casing collar comprises a steel tube extending between the two threaded ends claim 3 , and the steel tube has a wall thickness under the annular groove of at least a wall thickness of the casing joints so that the casing collar and the casing joints have comparable strengths.5. The apparatus as claimed claim 1 , wherein the casing collar has an outer cylindrical surface claim 1 , and the communication unit is situated in a pocket in the outer cylindrical surface.6. The apparatus ...

System and Method for Communicating Along a Casing String Including a High Magnetic Permeability Substrate

A communication assembly is described that when placed around a string casing in a wellbore transmits data along a pipe string from the wellbore to, for example, the surface of the well. The assembly includes a high magnetic permeability substrate to eliminate signal loss to the casing string thereby enhancing the signal and improving data transmission.

METHODS AND APPARATUS FOR EVALUATING DOWNHOLE CONDITIONS WITH RFID MEMS SENSORS

A radio frequency identification (RFID) tag can include a die attached to an inductive-capacitive (LC) circuit including a capacitive element coupled to an inductive element. The LC circuit can have a resonant frequency that varies according to properties of fluid proximate the RFID tag. The RFID tag can further include a coating material disposed around the die to form an outer surface of the RFID tag. The coating material may have a thickness over a portion of the LC circuit, to permit a conductivity property of a fluid proximate the outer surface to affect the resonant frequency of the LC circuit such that the resonant frequency shifts to a second resonant frequency. Additional apparatus, systems, and methods are disclosed. 1. A radio frequency identification (RFID) tag , comprising:a first die attached to a first inductive-capacitive (LC) circuit including a first capacitive element coupled to a first inductive element, the first LC circuit having a first resonant frequency; anda first coating material disposed around the first die to form a first outer surface of the RFID tag, the first coating material having a first thickness over a portion of the first LC circuit, the first coating configured to permit a conductivity property of a fluid proximate the first outer surface to affect the first resonant frequency of the first LC circuit such that the first resonant frequency shifts to a second resonant frequency.2. The RFID tag of claim 1 , further comprising:a second LC circuit including a second capacitive element coupled to a second inductive element, wherein the first coating material has a second thickness over a portion of the second LC circuit, the second thickness being different from the first thickness, the second thickness being such that the conductivity property of the fluid proximate the first outer surface does not affect a resonant frequency of the second LC circuit.3. The RFID tag of claim 2 , wherein the second LC circuit is formed on a second ...

Sensor Coil for Inclusion in an RFID Sensor Assembly

A communication assembly including at least one sensor assembly made up of interrogation circuitry and one or more antennae is described. The interrogation circuitry comprises at least one inductor coil sensor including a single turn coil inductor for reception of signals from the MEMS data sensors. 1. A method of making measurements in a borehole , comprising:providing a communication assembly in the borehole, wherein the communication assembly is configured to communicate with radio frequency identification device (RFID) tags in the borehole;wherein the communication assembly includes a sensing assembly comprising at least one induction coil sensor including at least one single turn coil;pumping a fluid into the borehole, the fluid containing a plurality of RFID tags; andinterrogating the plurality of RFID tags with the communication assembly to determine the presence or absence of RFID tags.2. The method of claim 1 , wherein the induction coil sensor comprises as least one third order bandpass filter where the single turn coil is the center inductor.3. The method of claim 2 , wherein the wire used to create the single coil comprises 8 AWG to 18 AWG wire.4. The method of claim 3 , wherein the wire is formed into a single loop of from about 10 mm to about 50 mm.5. The method of claim 2 , wherein the wire comprises 10 AWG to 12 AWG wire and the single loop diameter is from about 25 mm to about 35 mm.6. The method of claim 1 , further comprising placing a plurality of communication assembles in longitudinally spaced relation along a casing string placed in the borehole.7. The method of claim 2 , wherein each RFID sensor assembly includes a pair of induction coils and wherein the method further comprises:transmitting an interrogation signal to the RFID tags from a first induction coil; andreceiving a response signal from the RFID tags through the second induction coil.8. The method of claim 2 , wherein each RFID sensor assembly includes a single antenna claim 2 , and ...

Geometric Shaping of Radio-Frequency Tags Used in Wellbore Cementing Operations

Radio frequency Micro-Electro-Mechanical System (“MEMS”) tags are geometrically shaped using protective structures. The MEMS tags may be added to wellbore cement, and pumped downhole. In addition to protecting the MEMS tags from the harsh downhole environment, the protective structures produce a more rounded shape which, in turns, increases the flow efficiency of the MEMS tags. An interrogation tool may be deployed downhole to interrogate the MEMS tags, to thereby perform a variety of wellbore operations such as assessing the integrity of the cement seal. 1. A Micro-Electro-Mechanical System (“MEMS”) tag , comprising:a first planar structure having a first side and a second side opposite the first side;circuitry positioned on the first side of the first planar structure, the circuitry being configured to resonate at a resonant frequency, whereby the first planar structure and the circuitry form a first geometric shape; anda protective structure placed atop the circuitry, whereby the first planar structure, circuitry, and protective structure form a second geometric shape different from the first geometric shape.2. A MEMS tag as defined in claim 1 , wherein the protective structure is a second planar structure.3. A MEMS tag as defined in claim 2 , wherein the second planar structure is smaller than the first planar structure.4. A MEMS tag as defined in claim 2 , wherein the second planar structure comprises dimensions similar to dimensions of the first planar structure.5. A MEMS tag as defined in claim 1 , wherein the protective structure is a thick-film material having a thickness of 100 or more microns.6. A MEMS tag as defined in claim 5 , wherein the thick-film material comprises flow characteristics such that the thick-film material forms a rounded shape atop the circuitry.7. A MEMS tag as defined in claim 1 , wherein the second side comprises a second circuitry and a protective structure top the second circuitry.8. A MEMS tag as defined in claim 1 , wherein the ...

Multi-Coil RFID Sensor Assembly

A communication assembly including at least one sensor assembly made up of interrogation circuitry and one or more antennae is described. The interrogation circuitry comprises at least one inductor comprising at least two sensing coils for reception of signals from the MEMS data sensors. 1. A method of making measurements in a borehole , comprising:providing a communication assembly in the borehole, wherein the communication assembly is configured to communicate with radio frequency identification device (RFID) tags in the borehole;wherein the communication assembly includes a sensor assembly comprising at least one sensor having at least two sensor coils;pumping a fluid into the borehole, the fluid containing a plurality of RFID tags; andinterrogating the plurality of RFID tags with the communication assembly to determine the presence or absence of RFID tags within the borehole.2. The method of claim 1 , wherein the sensing assembly comprises as least one bandpass filter from 3to 18th order.3. The method of claim 1 , wherein each sensor coils is driven independently by its own circuit.4. The method of claim 1 , wherein all sensors are driven by a single circuit.5. The method of claim 1 , wherein the sensor has at least four sensor coils.6. The method of claim 1 , further comprising placing a plurality of communication assembles in longitudinally spaced relation along a casing string in the borehole.7. The method of claim 2 , wherein each RFID sensor assembly includes a pair of antennas claim 2 , and wherein the method further comprises:transmitting an interrogation signal to the RFID tags from a first antenna of the pair of antennas; andreceiving a response signal from the RFID tags through the second antenna of the pair of antennas.8. The method of claim 2 , wherein each RFID sensor assembly includes a single antenna claim 2 , and wherein the method further comprises:transmitting an interrogation signal to the RFID tags from the antenna; andreceiving a response ...

METHODS AND APPARATUS FOR EVALUATING DOWNHOLE CONDITIONS THROUGH RFID SENSING

An apparatus and method may operate to mount one or more communication assemblies relative to the exterior of a casing being placed in a borehole. Two communication assemblies can be placed in longitudinally spaced relation to one another along the casing, wherein each communication assembly is configured to obtain data from RFID tags in one or more azimuthally oriented regions of the annulus surrounding the casing, and to interrogate RFID tags in a first fluid in the borehole. Additional apparatus, systems, and methods are disclosed. 1. A method of making measurements in a well , comprising:associating a first communication assembly with the exterior of a casing string being placed in a borehole, wherein the first communication assembly is configured to communicate with radio frequency identification device (RFID) tags in the annulus surrounding the casing when the casing is in place within the borehole;wherein the first communication assembly includes a plurality of RFID sensor assemblies, with a first RFID sensor assembly configured to detect RFID tags in a first azimuthal area of the annulus, and a second RFID sensor assembly configured to detect tags in a second azimuthal region of the annulus, and wherein the first azimuthal region of the annulus is at least partially offset from the second azimuthal region of the annulus;pumping a first fluid into the annulus surrounding the casing, the fluid containing a first plurality of RFID tags; andinterrogating the first plurality of RFID tags by the first communication assembly to determine the presence or absence of RFID tags within the first and second azimuthal regions of the annulus proximate the depth of the first communication assembly.2. The method of claim 1 , wherein the first plurality of RFID tags in the first fluid are of a first configuration claim 1 , and wherein the method further comprises pumping a second fluid into the annulus claim 1 , the second fluid containing a second plurality of RFID tags of a ...

TIMELINE FROM SLUMBER TO COLLECTION OF RFID TAGS IN A WELL ENVIRONMENT

Sensor assemblies are deployed in a borehole for a well, such as an oil well or other hydrocarbon recovery well. The sensor assemblies are coupled to a casing string (e.g., the exterior of the casing), and may detect RFID tags or other properties of material (e.g., fluids) in an annulus surrounding the casing string. Limited battery power for the sensor assemblies and for assemblies for communicating sensed data may be a concern, and the sensor assemblies and communication assemblies may therefore operate in different modes of varying power consumption. In certain modes, sensing operations are curtailed (or expanded) depending on particular requirements. In one case, sensor operation is expanded during active portions of a cementing operation, and curtailed prior to and thereafter. Different triggering events may cause the sensor assembly to operate in different modes at different sensing frequencies. 1. A method of operating a downhole assembly coupled to a casing string in a borehole , comprising:operating a radio frequency identification device (RFID) sensor of the downhole assembly in a first detection mode, the RFID sensor configured to be responsive to RFID tags in an annulus surrounding the casing string in the borehole; andidentifying a first triggering event, and in response to the first triggering event, operating the RFID sensor assembly in a second detection mode.2. The method of operating a downhole assembly of claim 1 , wherein in the first detection mode the RFID sensor communicates an interrogation signal into the annulus at a first basis of reoccurrence claim 1 , and wherein in the second detection mode the RFID sensor communicates an interrogation signal into the annulus at a second basis of reoccurrence.3. The method of operating a downhole assembly of claim 1 , wherein the downhole assembly includes a plurality of RFID sensors claim 1 , each of which is configured to switch from the first detection mode to the second detection mode in response to ...

ALGORITHM FOR ZONAL FAULT DETECTION IN A WELL ENVIRONMENT

A hydrocarbon well (e.g., oil well) may be monitored during to determine whether a fault exists during an operation such as injecting sealant (e.g., cement) into the borehole. RFID tags may be mixed in a wellbore fluid (e.g., drilling mud, cement, etc.), placed into a borehole, and then tracked within the borehole by communication assemblies with RFID sensors. Data may be obtained by interrogating RFID tags in one or more azimuthally oriented regions of an annulus surrounding a casing of the borehole. Fluid distribution in the annulus will be evaluated with respect to azimuthally offset regions of the annulus. 1. A method , comprising:placing a first fluid into an annulus surrounding a casing in a borehole, the first fluid containing a first plurality of radio frequency identification device (RFID) tags;monitoring a plurality of azimuthally offset regions of the annulus for individual tags of the first plurality of RFID tags, the plurality of azimuthally offset regions including a first azimuthal region and a second azimuthal region at least partially offset from the first azimuthal region;detecting during a first time period, a number of the first plurality of RFID tags in the first azimuthal region; anddetecting during a second time period, a number of the first plurality of RFID tags in the second azimuthal region.2. The method of claim 1 , further comprising evaluating a volume of the first fluid proximate the first azimuthal region based in part on the number of RFID tags of the first plurality of RFID tags detected in the second annular region.3. The method of claim 1 , further comprising:placing a second fluid into the annulus, the second fluid containing a second plurality of RFID tags, the second plurality of RFID tags providing a different response to interrogation than the first plurality of RFID tags;monitoring a plurality of the azimuthally offset regions of the annulus for individual tags of the second plurality of RFID tags;detecting during a third ...

SYSTEMS AND METHODS FOR MONITORING MATERIALS

The present disclosure provides sensing systems and methods that are useful for monitoring materials (e.g., cement) via light diffusion to identify characteristics thereof and changes therein. The systems can utilize a light source, a light sensor, and light transmitting members combined with the material to be monitored. In use, light from the light source can be allowed to scatter through the material via the light transmitting members for detection by the light sensor. The data regarding the light transfer can be transmitted utilizing a communication interface and can be analyzed using data processing equipment. The systems and methods may particularly be utilized in monitoring the reinforcing cement positioned between the casing and the formation in an oil well. 1. A system for monitoring a characteristic of a material , the system comprising:a plurality of light transmitting members adapted for intermixture with the material;a light source;a light sensor; anda communication interface.2. The system according to claim 1 , wherein the material is a cementitious material.3. The system according to claim 1 , wherein the light transmitting members comprise fibers.4. The system according to claim 3 , wherein the fibers are glass fibers or optical fibers.5. The system according to claim 1 , wherein the light transmitting members are light diffusive.6. The system according to claim 1 , wherein the light source comprises a light emitting diode or a laser.7. The system according to claim 1 , wherein the light source is adapted for modulation by one or more of: on-off keying (OOK) with a duty cycle of about 1% to about 99%; pulse modulation with a duty cycle of less than 1% and a pulse duration of about 300 picoseconds to about 1 microsecond; sinusoidal AM modulation with a plurality of frequencies of about 100 Hz to about 100 MHz; and frequency modulated continuous wave (FMCW) with a chirp pattern in frequencies of about 100 Hz to about 100 MHz.8. The system according to ...

Determining Characteristics of a Fluid in a Wellbore

An assembly for use in a wellbore can include a plurality of sensors positioned external to a casing string. The plurality of sensors can be positioned for detecting an amount of a hydrocarbon that is present in a fluid in the wellbore and a pH of the fluid in the wellbore. The plurality of sensors can be positioned for wirelessly transmitting signals representing the amount of the hydrocarbon that is present in the fluid and the pH of the fluid to a receiving device. 1. A system comprising:a first sensor that is configured to float in a fluid in a wellbore for detecting an amount of a hydrocarbon that is present in the fluid and for wirelessly transmitting a first signal representing the amount of the hydrocarbon that is present in the fluid to a receiving device; anda second sensor positionable external to a casing string for detecting a pH of the fluid and for wirelessly transmitting a second signal representing the pH of the fluid to the receiving device;wherein the second sensor includes a computing device and a transceiver; andwherein the pH sensor is configured to supply a voltage to a power port of the computing device or the transceiver to power the computing device or the transceiver, respectively.2. The system of claim 1 , wherein the first sensor comprises a hydrocarbon sensor that includes two conductive electrodes positioned in parallel and with a gap between the two conductive electrodes claim 1 , wherein the gap forms a fluid communication path for the fluid to flow.3. The system of claim 2 , wherein the hydrocarbon sensor comprises:a processing device; and transmit a power signal with a frequency that is within a microwave range of frequencies to the two conductive electrodes;', 'detect an electrical characteristic associated with the two conductive electrodes; and', 'determine a type of the fluid based on the electrical characteristic., 'a memory device in which instructions executable by the processing device are stored for causing the processing ...

Toroidal System and Method for Communicating in a Downhole Environment

A communication assembly is described that, when placed along a string casing in a wellbore, may be used to transmit data along a pipe string from the wellbore to, for example, the surface of the well. The assembly includes toroidal transmission coil wrapped around an insulator core to enhancing the signal and improving data transmission. 1. A system for communicating from within a subterranean wellbore to the surface of the wellbore , comprising:a pipe string located within a subterranean wellbore, the pipe string comprising an exterior;a toroidal coil communication assembly at a location along the pipe string, the toroidal communication assembly comprising a toroidal transmission coil wrapped around an insulator core.2. The system of claim 1 , wherein the insulator core comprises a conductivity of less than 1 claim 1 ,000 Siemens/meter claim 1 ,3. The system of claim 1 , wherein the insulator core comprises a conductivity of less than 10 Siemens/meter.4. The system of claim 1 , where the insulator core comprises a conductivity of less than 1 Siemens/meter.5. The system of claim 1 , wherein the pipe sting comprises a casing string.6. The system of claim 1 , wherein the toroidal coil transmission wire may be chosen from copper claim 1 , aluminum claim 1 , steel claim 1 , silver claim 1 , and alloys thereof.7. The system of claim 1 , further comprising more than one toroidal communication assembly at spaced locations along the pipe string.8. The system of claim 1 , wherein the transmission coil comprises a copper coil.9. The system of claim 1 , wherein the insulating core is chosen from one or more of glass claim 1 , fiberglass claim 1 , porcelain claim 1 , clay claim 1 , quartz claim 1 , alumina claim 1 , feldspar claim 1 , polymeric materials claim 1 , A.B.S. claim 1 , acetates claim 1 , acrylics claim 1 , nylons claim 1 , polystyrenes claim 1 , polyimides claim 1 , fluoropolymers claim 1 , polyamides claim 1 , polyethyletherketones claim 1 , PET claim 1 , ...

Magnetic Surface Wave Effect to Probe Fluid Properties in a Wellbore

A magnetic signally assembly is described that when placed around a string casing in a wellbore can ascertain properties of the fluid in the annulus surrounding the string casing. Further, methods of using the magnetic signaling assembly to ascertain fluid properties and to indicate the condition of the well are also described.

Zonal Representation for Flow Visualization

Methods and systems are presented in this disclosure for determining information (e.g., visual information) about locations of different fluids flowing along a casing in a wellbore. A plurality of radio frequency (RF) micro-electro-mechanical system (MEMS) tags is placed in a plurality of fluids flowing through an annulus region between a casing string in the wellbore and a reservoir formation. At a plurality of sensing nodes located along the casing string, information about the fluids is gathered by communicating with the RF MEMS tags placed in the fluids. The information about fluid locations along the casing gathered by the sensing nodes is communicated to a receiving device, and appropriate operation in relation to the wellbore is performed based on the communicated information.

Dual Frequency Elements For Wellbore Communications

Methods and systems are presented in this disclosure for performing multi-frequency communications during wellbore operations. Communication of data related to a state of a wellbore (e.g., characteristics and/or locations of one or more fluids flowing along a casing in the wellbore during a cementing operation) can be performed simultaneously or sequentially involving a plurality of nodes located along the casing in the wellbore, wherein each of the nodes is configured to use a different frequency for communication. In this way, a higher information throughput and more reliable communication can be achieved during wellbore operations. 1. A method for performing multi-frequency communications in wellbore operations , the method comprising:performing data communication involving a plurality of nodes located along a casing in a wellbore, and by using multiple frequencies for the data communication.2. The method of claim 1 , wherein the data communication involving the plurality of nodes is performed simultaneously.3. The method of claim 1 , further comprising initiating one or more operations related to the wellbore based on the communicated data.4. The method of claim 1 , further comprising:configuring a first node of the plurality of nodes to use a first resonant frequency for the data communication; andconfiguring a second node of the plurality of nodes to use a second resonant frequency for the data communication, the first resonant frequency is lower than the second resonant frequency.5. The method of claim 4 , wherein:a first propagation range for the data communication associated with the first node is longer than a second propagation range for the data communication associated with the second node; ora first bandwidth for the data communication associated with the first node is smaller than a second bandwidth for the data communication associated with the second node.6. (canceled)7. The method of claim 4 , wherein:configuring the first node comprises wrapping ...

METHODS AND SYSTEMS FOR DETECTING RFID TAGS IN A BOREHOLE ENVIRONMENT

Sensor assemblies are deployed in a borehole for a well, such as an oil well or other hydrocarbon recovery well. The sensor assemblies may be coupled to a casing string (e.g., the exterior of the casing), and detect RFID tags or other properties of material (e.g., fluids) in an annulus surrounding the casing string. During cementing or other operations, RFID tags may be used to track fluids. RFID detection circuits may be used to scan at different frequencies, and corresponding results may be compared by various means and processes to determine the presence of RFID tags. 1. A method of detecting radio frequency identification device (RFID) tags in a borehole , comprising:scanning for RFID tags at a plurality of frequencies in at least a portion of an annulus surrounding an exterior of a casing string in the borehole;in response to said scanning, receiving a corresponding result for each of the plurality of frequencies; andcomparing a plurality of the corresponding results to one another to determine whether one or more RFID tags are present in the portion of the annulus.2. The method of claim 1 , wherein the received corresponding result for each frequency of the plurality of frequencies includes an analog value that indicates a power level reflected from a scan of the portion of the annulus.3. The method of claim 2 , further comprising prior to comparing the plurality of the corresponding results to one another claim 2 , applying a bandpass filter to the received corresponding result for each frequency of the plurality of frequencies to dampen environmental noise above and below a pair of respective threshold frequencies.4. The method of claim 2 , further comprising:at a first time, storing a first received scan result in an analog sample/hold circuit; andretrieving the stored first scan result from the analog sample/hold circuit at a later time; andwherein comparing the plurality of the scan results includes subtracting one of the first and second received scan ...

METHODS AND APPARATUS FOR EVALUATING DOWNHOLE CONDITIONS THROUGH FLUID SENSING

An apparatus and method may operate to mount one or more communication assemblies relative to the exterior of a casing being placed in a borehole. Two communication assemblies can be placed in longitudinally spaced relation to one another along the casing, wherein each communication assembly is configured to obtain excitation responses from electrodes of a fluid sensing component, where the excitation responses vary based on properties of fluids in one or more regions of the annulus surrounding the casing. Additional apparatus, systems, and methods are disclosed. 1. An assembly , comprising:a body member forming a portion of a casing string to be placed in an Earth borehole defined by formation sidewalls, and to then define an annulus between the casing string and the formation sidewalls;a first fluid sensing component supported by the body member, the first fluid sensing component including a first plurality of electrodes arranged to sense an electrical impedance between one or more pairs of electrodes of the first plurality of electrodes, wherein the electrical impedance varies based on properties of a material proximate the first fluid sensing component; and a signal generator provide excitation current to at least one electrode of the first plurality of electrodes, and', 'measurement circuitry to measure current or voltages resulting from the first excitation current traversing the material proximate the first sensing component, and', 'a data storage device configured to receive information associated with the determined fluid property., 'an electronics assembly supported by the body member and operably coupled to the first fluid sensing component, including,'}2. The assembly of claim 1 , wherein the assembly further comprises:a second fluid sensing component supported by the body member and angularly offset from the first fluid sensing component on the body member, the second fluid sensing component including a second plurality of electrodes and being ...

Dual-Frequency Tags to Detect Cement Curing in Wellbore Applications

Micro-Electro-Mechanical System (“MEMS”) tags having high and low resonant frequencies are used to detect the cured or uncured state of wellbore cement. The MEMS tags may be added to wellbore cement, and pumped downhole. An interrogation tool emits a signal at one or both of the resonant frequencies which, in turn, interacts with the MEMS tags to produce a response signal. Since uncured cement has a high attenuation, only the lower resonant frequency response signal is sensed by an interrogation device, thus indicating the cement remains uncured. When the cement cures, its conductivity drops and the attenuation of the higher resonant frequency response signal drops also, thus allowing that signal to be detected by the interrogation device and indicating the cement has cured. 1. A method to detect curing of cement in a wellbore , the method comprising:placing cement into the wellbore, the cement comprising one or more Micro-Electro-Mechanical System (“MEMS”) tags which resonate at a first resonant frequency and a second resonant frequency different from the first resonant frequency;emitting a signal into the wellbore at the first or second resonant frequency, wherein the signal interacts with the MEMS tags to produce a response signal;receiving the response signal; anddetermining whether the cement is uncured or cured based upon the response signal.2. A method as defined in claim 1 , wherein:the first resonant frequency is a frequency below which the signal efficiently propagates; andthe second resonant frequency is a frequency above which the signal is attenuated.3. A method as defined in claim 1 , wherein emitting the signal comprises emitting the signal at a first resonant frequency lower than 800 MHz.4. A method as defined in claim 1 , wherein emitting the signal comprises emitting the signal at a second resonant frequency higher than 800 MHz.5. A method as defined in claim 1 , wherein:placing the cement into the wellbore comprises pumping the cement into an ...

Determining Characteristics of a Fluid in a Wellbore

An assembly for use in a wellbore can include a plurality of sensors positioned external to a casing string. The plurality of sensors can be positioned for detecting an amount of a hydrocarbon that is present in a fluid in the wellbore and a pH of the fluid in the wellbore. The plurality of sensors can be positioned for wirelessly transmitting signals representing the amount of the hydrocarbon that is present in the fluid and the pH of the fluid to a receiving device. 1. A system for use in a wellbore , the system comprising:a plurality of sensors positioned external to a casing string for detecting an amount of a hydrocarbon that is present in a fluid in the wellbore and a pH of the fluid in the wellbore, and for wirelessly transmitting signals representing the amount of the hydrocarbon that is present in the fluid and the pH of the fluid to a receiving device.2. The system of claim 1 , wherein the plurality of sensors comprises a hydrocarbon sensor that includes two conductive electrodes positioned in parallel and with a gap between the two conductive electrodes claim 1 , wherein the gap forms a fluid communication path for the fluid to flow.3. The system of claim 2 , wherein the hydrocarbon sensor comprises:a processing device; and transmit a power signal with a frequency that is within a microwave range of frequencies to the two conductive electrodes;', 'detect an electrical characteristic associated with the two conductive electrodes; and', 'determine a type of the fluid based on the electrical characteristic., 'a memory device in which instructions executable by the processing device are stored for causing the processing device to4. The system of claim 1 , wherein the plurality of sensors comprises a pH sensor that includes two different conductive materials each coupled to a voltage-comparing device to compare a voltage generated across the two different conductive materials to a reference voltage to determine the pH of the fluid.5. The system of claim 1 , ...

Downhole Communications Using Selectable Modulation Techniques

A system that is positionable in a wellbore in a subterranean formation can include a first transceiver that is positionable external to a casing string in the wellbore. The first transceiver can wirelessly transmit data using a modulation technique that is selected from among multiple modulation techniques based on a fluid property of a fluid in the wellbore and a property of the subterranean formation. The system can also include a second transceiver that is positionable in the wellbore and operable to receive the data.

Electromagnetic Telemetry for Sensor Systems Deployed in a Borehole Environment

Disclosed are telemetry systems and methods that employ a plurality of electromagnetic transceivers disposed outside a well casing string at a corresponding plurality of depths along the casing string. Each transceiver includes one or more toroidal inductors circumferentially surrounding the casing string and inductively coupled thereto to allow signal transmission between transceivers via currents induced in the casing. In some embodiments, signals are relayed via a chain of transceivers to facilitate indirect communication between a surface facility and other transceivers located too deep for direct communication to the surface. 1. A telemetry system , comprising:a plurality of electromagnetic transceivers disposed outside a well casing string at a corresponding plurality of depths along the casing string, each transceiver comprising at least one toroidal inductor circumferentially surrounding the casing string, the plurality of transceivers including,a first transceiver configured to transmit a first signal comprising data from a first sensor proximate the first transceiver, anda second transceiver, located above and in spaced relation to the first transceiver, the second transceiver configured to receive the first signal from the first transceiver and to transmit a second signal that relays the data from the first sensor.2. The telemetry system of claim 1 , wherein the second transceiver is further configured to transmit data from a sensor proximate the second transceiver.3. The telemetry system of claim 1 , further comprising first and second concentric assemblies claim 1 , each concentric assembly extending around a respective length of casing within the casing string claim 1 , and wherein the first electromagnetic transceiver is coupled to the first concentric assembly claim 1 , and the second electromagnetic transceiver is coupled to the second concentric assembly4. The telemetry system of claim 3 , wherein each concentric assembly comprises a sleeve ...

Downhole Communications Using Variable Length Data Packets

A system that is positionable in a wellbore can include a transceiver that is positionable external to a casing string and programmable to vary a number of data packets that are wirelessly transmitted by the transceiver. The number of data packets can correspond to an amount of data wirelessly transmitted by the transceiver about an environment in the wellbore. 1. A system that is positionable in a wellbore , the system comprising:a transceiver that is positionable external to a casing string and programmable to vary a number of data packets that are wirelessly transmitted by the transceiver, the number of data packets corresponding to an amount of data wirelessly transmitted by the transceiver about an environment in the wellbore.2. The system of claim 1 , wherein the transceiver is remotely programmable subsequent to the transceiver being positioned in the wellbore.3. The system of claim 2 , further comprising a computing device positionable at a surface of the wellbore and operable to remotely program the transceiver by wirelessly transmitting a control signal to the transceiver.4. The system of claim 3 , wherein the transceiver comprises:a processing device; and receive the control signal; and', 'select, based on the control signal, a transmission mode from among at least three different transmission modes comprising a low data mode, a medium data mode, and a high data mode., 'a memory device in which instructions executable by the processing device are stored for causing the processing device to5. The system of claim 4 , wherein the memory device further comprises instructions executable by the processing device for causing the processing device to:control a first subset of a total amount of electrical devices when the transceiver is in the low data mode; andcontrol a second subset of the total amount of electrical devices when the transceiver is in the medium data mode, the first subset being less than the second subset.6. The system of claim 5 , wherein the ...

Synchronizing downhole communications using timing signals

A system that is positionable in a wellbore can include a transceiver that is positionable external to a casing string. The transceiver can be remotely programmable while in the wellbore to set an internal clock using a timing signal wirelessly transmitted from a source and a position of the transceiver in the wellbore relative to the source. The transceiver can use the internal clock for controlling a timing of the transceiver for transmitting a wireless signal.

Timeline from slumber to collection of RFID tags in a well environment

Sensor assemblies are deployed in a borehole for a well, such as an oil well or other hydrocarbon recovery well. The sensor assemblies are coupled to a casing string (e.g., the exterior of the casing), and may detect RFID tags or other properties of material (e.g., fluids) in an annulus surrounding the casing string. Limited battery power for the sensor assemblies and for assemblies for communicating sensed data may be a concern, and the sensor assemblies and communication assemblies may therefore operate in different modes of varying power consumption. In certain modes, sensing operations are curtailed (or expanded) depending on particular requirements. In one case, sensor operation is expanded during active portions of a cementing operation, and curtailed prior to and thereafter. Different triggering events may cause the sensor assembly to operate in different modes at different sensing frequencies.

Methods and apparatus for evaluating downhole conditions through RFID sensing

An apparatus and method may operate to mount one or more communication assemblies relative to the exterior of a casing being placed in a borehole. Two communication assemblies can be placed in longitudinally spaced relation to one another along the casing, wherein each communication assembly is configured to obtain data from RFID tags in one or more azimuthally oriented regions of the annulus surrounding the casing, and to interrogate RFID tags in a first fluid in the borehole. Additional apparatus, systems, and methods are disclosed.

Algorithm for zonal fault detection in a well environment

A hydrocarbon well (e.g., oil well) may be monitored during to determine whether a fault exists during an operation such as injecting sealant (e.g., cement) into the borehole. RFID tags may be mixed in a wellbore fluid (e.g., drilling mud, cement, etc.), placed into a borehole, and then tracked within the borehole by communication assemblies with RFID sensors. Data may be obtained by interrogating RFID tags in one or more azimuthally oriented regions of an annulus surrounding a casing of the borehole. Fluid distribution in the annulus will be evaluated with respect to azimuthally offset regions of the annulus.

Methods and systems for detecting RFID tags in a borehole environment

Sensor assemblies are deployed in a borehole for a well, such as an oil well or other hydrocarbon recovery well. The sensor assemblies may be coupled to a casing string (e.g., the exterior of the casing), and detect RFID tags or other properties of material (e.g., fluids) in an annulus surrounding the casing string. During cementing or other operations, RFID tags may be used to track fluids. RFID detection circuits may be used to scan at different frequencies, and corresponding results may be compared by various means and processes to determine the presence of RFID tags.

Sensor coil for inclusion in an RFID sensor assembly

A communication assembly including at least one sensor assembly made up of interrogation circuitry and one or more antennae. The interrogation circuitry comprises at least one inductor coil sensor including a single turn coil inductor for reception of signals from the MEMS data sensors.

Multi-coil RFID sensor assembly

A communication assembly including at least one sensor assembly made up of interrogation circuitry and one or more antennae is described. The interrogation circuitry comprises at least one inductor comprising at least two sensing coils for reception of signals from the MEMS data sensors.

Geometric shaping of radio-frequency tags used in wellbore cementing operations

Radio frequency Micro-Electro-Mechanical System ("MEMS") tags are geometrically shaped using protective structures. The MEMS tags may be added to wellbore cement, and pumped downhole. In addition to protecting the MEMS tags from the harsh downhole environment, the protective structures produce a more rounded shape which, in turns, increases the flow efficiency of the MEMS tags. An interrogation tool may be deployed downhole to interrogate the MEMS tags, to thereby perform a variety of wellbore operations such as assessing the integrity of the cement seal.

Duel frequency elements for wellbore communications

Methods and systems are presented in this disclosure for performing multi-frequency communications during wellbore operations. Communication of data related to a state of a wellbore (e.g., characteristics and/or locations of one or more fluids flowing along a casing in the wellbore during a cementing operation) can be performed simultaneously or sequentially involving a plurality of nodes located along the casing in the wellbore, wherein each of the nodes is configured to use a different frequency for communication. In this way, a higher information throughput and more reliable communication can be achieved during wellbore operations.

Dual frequency elements for wellbore telecommunications

Les procédés et les systèmes présentés dans cette description permettent d'effectuer des télécommunications multifréquences pendant des opérations relatives à un puits de forage. La télécommunication de données liées à un état d'un puits de forage (par ex. les caractéristiques et/ou les emplacements d'au moins un fluide s'écoulant le long d'un tubage dans le puits de forage pendant une opération de cimentation) peut avoir lieu simultanément ou successivement en impliquant une pluralité de nœuds situés le long du tubage dans le puits de forage, chacun des nœuds étant conçu pour utiliser une fréquence différente de télécommunication. Ainsi, on peut obtenir un débit plus élevé d'informations et un niveau plus fiable de télécommunication pendant les opérations relatives au puits de forage.

ZONAL REPRESENTATION FOR FLOW VISUALIZATION

La présente divulgation présente des procédés (600, 700) et des systèmes permettant la détermination d'informations (par ex., des informations visuelles) concernant des emplacements de différents fluides (105) s'écoulant le long d'un tubage dans un puits de forage (102). Une pluralité de marqueurs (300) de radiofréquence (RF) de système microélectromécanique (MEMS) sont placés dans une pluralité de fluides (105) s'écoulant à travers une région d'anneau (107) entre un train de tubage (106) dans le puits de forage (102) et une formation de réservoir. Au niveau d'une pluralité de nœuds de détection (118) localisés le long du train de tubage (106), des informations concernant les fluides (105) sont collectées en communiquant avec les marqueurs (300) RF MEMS placés dans les fluides (105). Les informations concernant les emplacements de fluide le long du tubage, qui sont collectées par les nœuds de détection (118), sont transmises à au moins un dispositif de réception (124, 126), et une opération appropriée en relation avec le puits de forage (102) est réalisée sur la base des informations transmises. The present disclosure discloses methods (600, 700) and systems for determining information (e.g., visual information) relating to locations of different fluids (105) flowing along a casing in a well. drilling (102). A plurality of microelectromechanical system (MEMS) radiofrequency (RF) markers (300) are placed in a plurality of fluids (105) flowing through a ring region (107) between a tubing string (106) in a the wellbore (102) and a reservoir formation. At a plurality of detection nodes (118) located along the casing string (106), fluid information (105) is collected by communicating with the RF MEMS markers (300) placed in the fluids (105). ). Information regarding fluid locations along the casing, which are collected by the detection nodes (118), is transmitted to at least one receiving device (124, 126), and an appropriate operation in ...

Methods and apparatus for evaluating downhole conditions through rfid sensing

An apparatus and method may operate to mount one or more communication assemblies relative to the exterior of a casing being placed in a borehole. Two communication assemblies can be placed in longitudinally spaced relation to one another along the casing, wherein each communication assembly is configured to obtain data from RFID tags in one or more azimuthally oriented regions of the annulus surrounding the casing, and to interrogate RFID tags in a first fluid in the borehole. Additional apparatus, systems, and methods are disclosed.

TOROIDAL SYSTEM AND METHOD FOR COMMUNICATING IN A WELL BOTTOM ENVIRONMENT

La présente divulgation décrit notamment un module de communication qui, lorsqu'il est placé le long d'un train de tubage (100) dans un puits de forage (200), peut être utilisé pour transmettre des données le long d'un train de tiges à partir du puits de forage (200) vers, par ex., la surface du puits. Le module comprend une bobine de transmission toroïdale (250) enroulée autour d'un noyau d'isolation (350) pour améliorer le signal et améliorer la transmission de données. The present disclosure notably describes a communication module which, when placed along a casing string (100) in a wellbore (200), can be used to transmit data along a train of rods from the wellbore (200) to, eg, the well surface. The module includes a toroidal transmission coil (250) wrapped around an isolation core (350) to enhance the signal and improve data transmission.

TOROIDAL SYSTEM AND METHOD FOR COMMUNICATING IN A WELL BOTTOM ENVIRONMENT

Sensor coil for inclusion in an rfid sensor assembly

A communication assembly including at least one sensor assembly made up of interrogation circuitry and one or more antennae is described. The interrogation circuitry comprises at least one inductor coil sensor including a single turn coil inductor for reception of signals from the MEMS data sensors.

Downhole communications using frequency guard bands

A system that is positionable in a wellbore can include a chain of transceivers that are positionable external to a casing string. Each transceiver in the chain of transceivers can be operable to transmit a wireless signal using a separate frequency guard band that is assigned to that transceiver and to receive wireless signals using another frequency guard band assigned to a prior transceiver in the chain of transceivers.

Downhole communications using selectable modulation techniques

A system that is positionable in a wellbore in a subterranean formation can include a first transceiver that is positionable external to a casing string in the wellbore. The first transceiver can wirelessly transmit data using a modulation technique that is selected from among multiple modulation techniques based on a fluid property of a fluid in the wellbore and a property of the subterranean formation. The system can also include a second transceiver that is positionable in the wellbore and operable to receive the data.

Timeline from slumber to collection of rfid tags in a well environment.

Se introducen montajes de sensores en un agujero de pozo para un pozo, tal como un pozo de petróleo u otro pozo de recuperación de hidrocarburos. Los montajes de sensores se encuentran acoplados a una sarta de revestimiento (por ejemplo, el exterior de la tubería de revestimiento) y pueden detectar etiquetas RFID u otras propiedades de material (por ejemplo, fluidos) en un espacio anular alrededor de la sarta de revestimiento. Puede resultar preocupante que la energía de las baterías para los montajes de sensor y para que los montajes comuniquen los datos detectados sea limitada y, por lo tanto, los montajes de sensor y los montajes de comunicación pueden operar en distintos modos de consumo energético variantes. En determinados modos, las operaciones de detección se restringen (o se expanden) conforme a requisitos particulares. En un caso, la operación de sensor se expande durante las partes activas de una operación de cementación y se restringe previa y posteriormente a esta. Los distintos eventos desencadenantes pueden hacer que el montaje de sensor opere en diferentes modos y a diferentes frecuencias de detección.

Methods and apparatus for evaluating downhole conditions through fluid sensing

An apparatus and method may operate to mount one or more communication assemblies relative to the exterior of a casing being placed in a borehole. Two communication assemblies can be placed in longitudinally spaced relation to one another along the casing, wherein each communication assembly is configured to obtain excitation responses from electrodes of a fluid sensing component, where the excitation responses vary based on properties of fluids in one or more regions of the annulus surrounding the casing. Additional apparatus, systems, and methods are disclosed.

Toroidal system and method for communicating in a downhole environment

A communication assembly is described that, when placed along a string casing in a wellbore, may be used to transmit data along a pipe string from the wellbore to, for example, the surface of the well. The assembly includes toroidal transmission coil wrapped around an insulator core to enhancing the signal and improving data transmission.

Dynamic sensing of the top of cement (TOC) during cementing of a well casing in a well bore

A well casing is cemented in a well bore in a subterranean formation by pumping cement slurry down into the well casing so that the cement slurry flows up into an annulus surrounding the well casing. While pumping the cement slurry, the position of the top of the cement slurry in the annulus is sensed, and the rise of the sensed position of the top of the cement slurry in the annulus is recorded as a function of time. The recording is analyzed to evaluate the cement job. For example, the analysis may indicate a problem addressed by adjusting a cement plan for a future cement job, and the analysis may indicate a need to repair a location of the set cement by perforating the well casing at the location to be repaired, and pumping cement slurry down the well casing to fill the location to be repaired.

Dynamic sensing of the top of cement (toc) during cementing of a well casing in a well bore

A well casing is cemented in a well bore in a subterranean formation by pumping cement slurry down into the well casing so that the cement slurry flows up into an annulus surrounding the well casing. While pumping the cement slurry, the position of the top of the cement slurry in the annulus is sensed, and the rise of the sensed position of the top of the cement slurry in the annulus is recorded as a function of time. The recording is analyzed to evaluate the cement job. For example, the analysis may indicate a problem addressed by adjusting a cement plan for a future cement job, and the analysis may indicate a need to repair a location of the set cement by perforating the well casing at the location to be repaired, and pumping cement slurry down the well casing to fill the location to be repaired.

Downhole fluid detection using surface waves

A communication system that is positionable in a wellbore can include a first transceiver positioned externally to a casing string. The first transceiver can be operable to detect a presence or an absence of a surface wave; determine a location of a fluid in the wellbore based on the presence or the absence of the surface wave; and transmit data indicative of the location to a second transceiver. The surface wave can include an electromagnetic wave that has a magnetic field or an electric field that is non-transverse to a direction of propagation of the surface wave. The communication system can also include the second transceiver, which can be positioned externally the casing string and operable to receive the data.

Dual frequency elements for wellbore communications

Methods and systems are presented in this disclosure for performing multi-frequency communications during wellbore operations. Communication of data related to a state of a wellbore (e.g., characteristics and/or locations of one or more fluids flowing along a casing in the wellbore during a cementing operation) can be performed simultaneously or sequentially involving a plurality of nodes located along the casing in the wellbore, wherein each of the nodes is configured to use a different frequency for communication. In this way, a higher information throughput and more reliable communication can be achieved during wellbore operations.

Timeline from slumber to collection of RFID tags in a well environment

Geometric shaping of radio-frequency tags used in wellbore cementing operations

Radio frequency Micro-Electro-Mechanical System (“MEMS”) tags are geometrically shaped using protective structures. The MEMS tags may be added to wellbore cement, and pumped downhole. In addition to protecting the MEMS tags from the harsh downhole environment, the protective structures produce a more rounded shape which, in turns, increases the flow efficiency of the MEMS tags. An interrogation tool may be deployed downhole to interrogate the MEMS tags, to thereby perform a variety of wellbore operations such as assessing the integrity of the cement seal.

Cathode structure for a plasma addressed liquid crystal display panel

? set, system, and method for taking measurements in a well?

um aparelho e método podem operar para montar um ou mais conjuntos de comunicação em relação a parte exterior de um tubo de revestimento sendo colocada em um furo de poço. dois conjuntos de comunicação podem ser colocados em relação espaçada longitudinalmente um ao outro ao longo do tubo de revestimento, em que cada módulo de comunicação é configurado para obter respostas de excitação a partir de eletrodos de um componente de detecção de fluidos, em que as respostas de excitação variam com base nas propriedades de fluidos em uma ou mais regiões do espaço anular em torno do tubo de revestimento. aparelho, sistemas e métodos adicionais são divulgados. An apparatus and method may operate to mount one or more communication assemblies with respect to the outside of a casing pipe being placed in a wellbore. two communication sets may be placed in longitudinally spaced relationship along the casing, wherein each communication module is configured to obtain excitation responses from electrodes of a fluid sensing component, wherein the responses Excitation values vary based on fluid properties in one or more regions of the annular space around the liner tube. Additional apparatus, systems and methods are disclosed.

Determining characteristics of a fluid in a wellbore

An assembly for use in a wellbore can include a plurality of sensors positioned external to a casing string. The plurality of sensors can be positioned for detecting an amount of a hydrocarbon that is present in a fluid in the wellbore and a pH of the fluid in the wellbore. The plurality of sensors can be positioned for wirelessly transmitting signals representing the amount of the hydrocarbon that is present in the fluid and the pH of the fluid to a receiving device.

Methods and apparatus for evaluating downhole conditions with rfid mems sensors

A radio frequency identification (RFID) tag can include a die attached to an inductive-capacitive (LC) circuit including a capacitive element coupled to an inductive element. The LC circuit can have a resonant frequency that varies according to properties of fluid proximate the RFID tag. The RFID tag can further include a coating material disposed around the die to form an outer surface of the RFID tag. The coating material may have a thickness over a portion of the LC circuit, to permit a conductivity property of a fluid proximate the outer surface to affect the resonant frequency of the LC circuit such that the resonant frequency shifts to a second resonant frequency. Additional apparatus, systems, and methods are disclosed.

Methods and apparatus for evaluating downhole conditions with rfid mems sensors

A radio frequency identification (RFID) tag can include a die attached to an inductive-capacitive (LC) circuit including a capacitive element coupled to an inductive element. The LC circuit can have a resonant frequency that varies according to properties of fluid proximate the RFID tag. The RFID tag can further include a coating material disposed around the die to form an outer surface of the RFID tag. The coating material may have a thickness over a portion of the LC circuit, to permit a conductivity property of a fluid proximate the outer surface to affect the resonant frequency of the LC circuit such that the resonant frequency shifts to a second resonant frequency. Additional apparatus, systems, and methods are disclosed.

Downhole communications using selectable modulation techniques

A system that is positionable in a wellbore in a subterranean formation can include a first transceiver that is positionable external to a casing string in the wellbore. The first transceiver can wirelessly transmit data using a modulation technique that is selected from among multiple modulation techniques based on a fluid property of a fluid in the wellbore and a property of the subterranean formation. The system can also include a second transceiver that is positionable in the wellbore and operable to receive the data.

apparatus and method

uma unidade de comunicação está situada dentro ou sobre um anel de revestimento. o anel de revestimento tem duas extremidades roscadas para unir as juntas de revestimento para construir um revestimento de poço, e uma unidade de comunicação está disposta em ou sobre uma região central do tubo entre as duas extremidades roscadas. em um exemplo, a unidade de comunicação possui um transmissor para transmitir para superfície de poço os dados do sensor a partir de um sensor que detecta uma condição de poço. por exemplo, a unidade de comunicação possui um receptor para receber dados de sensores dos sensores dos sistemas microeletromecânicos (mems), um transceptor para interrogação de etiquetas rfid, um transceptor acústico para detecção de condições de poço, sensor de pressão, sensor de temperatura e baterias para alimentar a unidade de comunicação. A communication unit is located within or above a casing ring. the casing ring has two threaded ends for joining the casing joints to construct a well casing, and a communication unit is arranged at or about a central region of the tube between the two threaded ends. In one example, the communication unit has a transmitter for transmitting sensor data to the well surface from a sensor that detects a well condition. for example, the communication unit has a receiver for receiving sensor data from microelectromechanical system (mems) sensors, an RFID tag interrogation transceiver, an acoustic transceiver for well condition detection, pressure sensor, temperature sensor, and batteries to power the communication unit.

Algorithm for zonal fault detection in a well environment

A hydrocarbon well (e.g., oil well) may be monitored during to determine whether a fault exists during an operation such as injecting sealant (e.g., cement) into the borehole. RFID tags may be mixed in a wellbore fluid (e.g., drilling mud, cement, etc.), placed into a borehole, and then tracked within the borehole by communication assemblies with RFID sensors. Data may be obtained by interrogating RFID tags in one or more azimuthally oriented regions of an annulus surrounding a casing of the borehole. Fluid distribution in the annulus will be evaluated with respect to azimuthally offset regions of the annulus.

Downhole communications using frequency guard bands

A system that is positionable in a wellbore can include a chain of transceivers that are positionable external to a casing string. Each transceiver in the chain of transceivers can be operable to transmit a wireless signal using a separate frequency guard band that is assigned to that transceiver and to receive wireless signals using another frequency guard band assigned to a prior transceiver in the chain of transceivers.

Repeater for a wellbore

A repeater system provided in a wellbore including a plurality of communication units spaced at intervals along a length of a wellbore, the communication units being communicatively coupled via a transmission medium. The communication units are configured to relay data from one communication unit to another communication unit selected from the plurality of communication units along the transmission medium, wherein at least one of the communication units is hopped over as data is relayed across the plurality of communication units along the length of the wellbore.

Repeater for a wellbore

Magnetic surface wave effect to probe fluid properties in a wellbore

A magnetic signally assembly is described that when placed around a string casing in a wellbore can ascertain properties of the fluid in the annulus surrounding the string casing. Further, methods of using the magnetic signaling assembly to ascertain fluid properties and to indicate the condition of the well are also described.

communication system and method

um sistema de comunicação que é posicionável em um poço de exploração pode incluir um primeiro transmissor posicionado externamente em relação a uma coluna de revestimento. o primeiro transmissor pode ser operável para detectar uma presença ou ausência de uma onda de superfície; determinar uma localização de um fluido no poço de exploração com base na presença ou na ausência da onda de superfície; e transmite dados indicativos da localização para um segundo transmissor. a onda de superfície pode incluir uma onda eletromagnética que tenha um campo magnético ou um campo elétrico que não é transversal a uma direção de propagação da onda de superfície. o sistema de comunicação também pode incluir o segundo transmissor, que pode ser posicionado externamente à coluna de revestimento e operável para receber os dados. A communication system that is positionable in an exploration well may include a first transmitter positioned externally relative to a casing column. the first transmitter may be operable to detect the presence or absence of a surface wave; determining a location of a fluid in the exploration well based on the presence or absence of the surface wave; and transmits location indicative data to a second transmitter. The surface wave may include an electromagnetic wave that has a magnetic field or an electric field that is not transverse to a surface wave propagation direction. The communication system may also include the second transmitter, which may be positioned externally to the casing column and operable to receive the data.

assembly, system and antenna for indoor communication using surface waves.

trata-se de um conjunto que pode incluir uma coluna de revestimento com uma superfície externa. o conjunto pode incluir também uma antena para comunicar dados de modo sem fio gerando-se uma onda de superfície que se propaga ao longo de uma superfície de interface. a antena pode estar posicionada coaxialmente em torno da coluna de revestimento. a antena pode incluir um condutor com formato cilíndrico que é posicionável coaxialmente em torno de uma superfície externa de uma coluna de revestimento para gerar um componente de campo magnético da onda de superfície que é não transversal a uma direção de propagação da onda de superfície ao longo da superfície de interface. a antena pode incluir também um par de placas condutoras posicionado num ângulo em relação ao condutor com formato cilíndrico para gerar um componente de campo elétrico da onda de superfície. It is an assembly which may include a casing column with an outer surface. The assembly may also include an antenna for wirelessly communicating data generating a surface wave propagating along an interface surface. The antenna may be coaxially positioned around the casing column. The antenna may include a cylindrically shaped conductor that is coaxially positionable around an outer surface of a casing column to generate a surface wave magnetic field component that is non-transverse to a surface wave propagation direction along of the interface surface. The antenna may also include a pair of conductor plates positioned at an angle to the cylindrically shaped conductor to generate an electric field component of the surface wave.

MAGNETIC SURFACE WAVE EFFECT ON PROBE FLUID PROPERTIES IN A WELLBORE

Zonal representation for flow visualization

Methods and systems are presented in this disclosure for determining information (e.g., visual information) about locations of different fluids flowing along a casing in a wellbore. A plurality of radio frequency (RF) micro-electro-mechanical system (MEMS) tags is placed in a plurality of fluids flowing through an annulus region between a casing string in the wellbore and a reservoir formation. At a plurality of sensing nodes located along the casing string, information about the fluids is gathered by communicating with the RF MEMS tags placed in the fluids. The information about fluid locations along the casing gathered by the sensing nodes is communicated to a receiving device, and appropriate operation in relation to the wellbore is performed based on the communicated information.

Determining characteristics of a fluid in a wellbore

Timeline from slumber to collection of rfid tags in a well environment

Sensor assemblies are deployed in a borehole for a well, such as an oil well or other hydrocarbon recovery well. The sensor assemblies are coupled to a casing string (e.g., the exterior of the casing), and may detect RFID tags or other properties of material (e.g., fluids) in an annulus surrounding the casing string. Limited battery power for the sensor assemblies and for assemblies for communicating sensed data may be a concern, and the sensor assemblies and communication assemblies may therefore operate in different modes of varying power consumption. In certain modes, sensing operations are curtailed (or expanded) depending on particular requirements. In one case, sensor operation is expanded during active portions of a cementing operation, and curtailed prior to and thereafter. Different triggering events may cause the sensor assembly to operate in different modes at different sensing frequencies.

Algorithm for zonal fault detection in a well environment.

Se puede controlar un pozo de hidrocarburos (por ejemplo, pozo petrolífero) para determinar si existe una falla durante una operación como la inyección de un sellador (por ejemplo, cemento) en el pozo de sondeo. Las etiquetas RFID se pueden mezclar en un fluido de pozo (por ejemplo, lodo de perforación, cemento, etc.), se pueden colocar en un pozo de sondeo y luego se pueden rastrear dentro del pozo de sondeo mediante montajes de comunicación con sensores RFID. Se pueden obtener datos mediante el análisis de etiquetas RFID en una o más regiones desviadas de manera acimutal de un espacio anular que rodea una tubería de revestimiento del pozo de sondeo. Se evaluará la distribución de fluido en el espacio anular con respecto a las regiones desviadas de manera acimutal del espacio anular.

Remote actuation of downhole sensors

Structure for a plasma addressed liquid crystal display panel having a helium filling doped with hydrogen

An anode (24) in a channel (20) of a PALC display panel has an upper surface of a material that is electrically conductive and is non-oxidizing.

Structure for a plasma addressed liquid crystal display panel having a helium filling doped with hydrogen

An anode (24) in a channel (20) of a PALC display panel has an upper surface of a material that is electrically conductive and is non-oxidizing.

Dual-frequency tags to detect cement curing in wellbore applications

Repeater for a wellbore

A repeater system provided in a wellbore including a plurality of communication units spaced at intervals along a length of a wellbore, the communication units being communicatively coupled via a transmission medium. The communication units are configured to relay data from one communication unit to another communication unit selected from the plurality of communication units along the transmission medium, wherein at least one of the communication units is hopped over as data is relayed across the plurality of communication units along the length of the wellbore.

Electromagnetic emission source identification apparatus and associated method, computer device, and computer software program product

An electromagnetic emission source identification apparatus (100) comprising a sensor device (200), a data transmitter (400), and a computer (600). The sensor device (200) senses electromagnetic emission data from a source (700), which is transmitted to the computer (600) by the transmitter (400) before or after conversion to digital emission data. The computer (600) processes the digital emission data so as to determine an identification indicator, an operational characteristic indicator, and/or an accessory characteristic indicator corresponding to the source (700) and then compares to this,corresponding indicators of each of a plurality of known sources in a database and determines a best-match therebetween. Associated methods as well as an associated computer device and computer software program product are also provided.

Patent FR3041199A1

Les procédés et les systèmes présentés dans cette description permettent d'effectuer des télécommunications multifréquences pendant des opérations relatives à un puits de forage. La télécommunication de données liées à un état d'un puits de forage (par ex. les caractéristiques et/ou les emplacements d'au moins un fluide s'écoulant le long d'un tubage dans le puits de forage pendant une opération de cimentation) peut avoir lieu simultanément ou successivement en impliquant une pluralité de nœuds situés le long du tubage dans le puits de forage, chacun des nœuds étant conçu pour utiliser une fréquence différente de télécommunication. Ainsi, on peut obtenir un débit plus élevé d'informations et un niveau plus fiable de télécommunication pendant les opérations relatives au puits de forage. The methods and systems presented in this specification enable multi-frequency telecommunications during wellbore operations. The telecommunication of data related to a state of a wellbore (eg the characteristics and / or locations of at least one fluid flowing along a casing in the wellbore during a cementing operation ) can occur simultaneously or successively by involving a plurality of nodes located along the casing in the wellbore, each of the nodes being designed to use a different telecommunication frequency. Thus, a higher information rate and a more reliable level of telecommunication can be obtained during the wellbore operations.

Zonal representation for flow visualization

Methods and systems are presented in this disclosure for determining information (e.g., visual information) about locations of different fluids flowing along a casing in a wellbore. A plurality of radio frequency (RF) micro-electro-mechanical system (MEMS) tags is placed in a plurality of fluids flowing through an annulus region between a casing string in the wellbore and a reservoir formation. At a plurality of sensing nodes located along the casing string, information about the fluids is gathered by communicating with the RF MEMS tags placed in the fluids. The information about fluid locations along the casing gathered by the sensing nodes is communicated to a receiving device, and appropriate operation in relation to the wellbore is performed based on the communicated information.

Toroidal system and method for communicating in a downhole environment

A communication assembly is described that, when placed along a string casing in a wellbore, may be used to transmit data along a pipe string from the wellbore to, for example, the surface of the well. The assembly includes toroidal transmission coil wrapped around an insulator core to enhancing the signal and improving data transmission.

method for making measurements in a hole, communication set and system for use in a hole, and detection set.

é descrito um conjunto de comunicação que inclui pelo menos um conjunto de sensor composto por circuitos de interrogação e uma ou mais antenas. o circuito de interrogação compreende pelo menos um sensor de bobina de indução que inclui um indutor de bobina única para recepção de sinais dos sensores de dados mems. A communication set comprising at least one sensor assembly comprising interrogation circuits and one or more antennas is described. the interrogation circuit comprises at least one induction coil sensor including a single coil inductor for receiving signals from the mems data sensors.

Synchronizing downhole communications using timing signals

A system that is positionable in a wellbore can include a transceiver that is positionable external to a casing string. The transceiver can be remotely programmable while in the wellbore to set an internal clock using a timing signal wirelessly transmitted from a source and a position of the transceiver in the wellbore relative to the source. The transceiver can use the internal clock for controlling a timing of the transceiver for transmitting a wireless signal.

Geometric shaping of radio-frequency tags used in wellbore cementing operations

Radio frequency Micro-Electro-Mechanical System ("MEMS") tags are geometrically shaped using protective structures. The MEMS tags may be added to wellbore cement, and pumped downhole. In addition to protecting the MEMS tags from the harsh downhole environment, the protective structures produce a more rounded shape which, in turns, increases the flow efficiency of the MEMS tags. An interrogation tool may be deployed downhole to interrogate the MEMS tags, to thereby perform a variety of wellbore operations such as assessing the integrity of the cement seal.

Timeline from slumber to collection of RFID tags in a well environment

Synchronizing downhole communications using timing signals

A system (100) that is positionable in a wellbore (102) can include a transceiver (118a, 118b, 118c) that is positionble external to a casing string (106). The transceiver (118a, 118b, 118c) can be remotely programmable while in the wellbore (102) to set an internal clock using a timing signal wirelessly transmitted from a source and a position of the transceiver (118a, 118b, 118c) in the wellbore (102) relative to the source. The transceiver (118a, 118b, 118c) can use the internal clock for controlling a timing of the transceiver (118a, 118b, 118c) for transmitting a wireless signal.

Electromagnetic telemetry for sensor systems deployed in a borehole environment

Comunicacion inalambrica en el interior del pozo mediante el uso de ondas de superficie.

Un sistema de comunicación que puede colocarse en un pozo puede incluir un primer transceptor para el acoplamiento de forma externa con respecto a una sarta de revestimiento. El primer transceptor puede ser para la transmisión de datos de forma inalámbrica mediante la generación y modulación de una onda de superficie que se propaga a lo largo de una superficie de interfaz. La onda de superficie puede incluir una onda electromagnética que tiene un campo magnético o un campo eléctrico que se encuentra en un ángulo agudo con respecto a una dirección de propagación de la onda de superficie. El sistema de comunicación también puede incluir un segundo transceptor para el acoplamiento a la sarta de revestimiento y para recibir, de forma inalámbrica, la onda de superficie y detectar los datos.

Downhole communications using variable length data packets

Comunicaciones en el interior del pozo mediante el uso de bandas de frecuencia seleccionables.

Un sistema que puede posicionarse en un agujero en una formación subterránea puede incluir un primer transceptor que puede posicionarse de forma externa a una sarta de revestimiento en el agujero. El primer transceptor puede transmitir de forma inalámbrica los datos mediante una señal dentro de una banda de frecuencia que se selecciona en función de una propiedad de fluido de un fluido en el agujero y una propiedad de la formación subterránea. El sistema también puede incluir un segundo transceptor que puede posicionarse de forma externa a la sarta de revestimiento y operable para recibir la señal.

Sincronizacion de comunicaciones en el fondo del pozo usando señales de tiempo.

Un sistema que se puede colocar en un pozo puede incluir un transceptor que se puede colocar externo a una sarta de revestimiento. El transceptor se puede programar de forma remota mientras está en el pozo para establecer un reloj interno usando una señal de tiempo transmitida de forma inalámbrica desde una fuente y una posición del transceptor en el pozo con relación a la fuente. El transceptor puede usar el reloj interno para controlar un tiempo del transceptor para transmitir una señal inalámbrica.

Electromagnetic telemetry for sensor systems deployed in a borehole environment

プラズマ・アドレス液晶パネル用チャンネル・サブアッセンブリ及びその製造方法

(57)【要約】 【課題】 ＰＡＬＣ表示パネルの使用時間経過に伴って ドーパント・ガスを補充することにより、ＰＡＬＣ表示 パネルの寿命にわたって、その表示品質を維持する。 【解決手段】 チャンネル部材４の相互接続されたチャ ンネル２０の配列をカバー・シート６で覆い、密閉され た空間を形成する。この密閉された空間内にイオン化可 能なガス及び水素の混合気を封入する。また、この空間 と結合した位置に、約３３ｗｔ％のＺｒ、約３３ｗｔ％ のＦｅ及び約３３ｗｔ％のＶを含む合金３６を配置さ せ、この合金から水素を補充する。

Plasma addressed liquid crystal display panel with integrated source of hydrogen

Modulatable reflectors and methods for using same

A reflector having a mechanically deformable portion (12) of at least one reflective surface is disclosed. By deforming the portion of the reflective surface, discontinuity is introduced in that portion of the reflective surface. The discontinuity in the reflective surface scatters incident radiation signals (20) so as to cause attenuation in the reflective signal (22). By selectively deforming the portion of the reflective surface, the reflected signal can be modulated to encode data thereon. The mechanically deformable portion of the reflective surface preferably comprises plates integrally formed therein. In one embodiment, the reflector takes the form of a corner-cube reflector (10). The use of a reflector with a three dimensional pattern (122) on the reflective surface on the encoding data on a reflected signal, which functions much like a barcode pattern, is also disclosed. One application of the applicator is in the identification of friend or foes (IFF).