CA2683442A1 - System and method for receiving and decoding electromagnetic transmissions within a well - Google Patents

System and method for receiving and decoding electromagnetic transmissions within a well Download PDF

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Publication number
CA2683442A1
CA2683442A1 CA002683442A CA2683442A CA2683442A1 CA 2683442 A1 CA2683442 A1 CA 2683442A1 CA 002683442 A CA002683442 A CA 002683442A CA 2683442 A CA2683442 A CA 2683442A CA 2683442 A1 CA2683442 A1 CA 2683442A1
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CA
Canada
Prior art keywords
frequency
energy pulse
downhole
transducer
reflected
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CA002683442A
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French (fr)
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CA2683442C (en
Inventor
Clark M. Thompson
Don M. Coates
David W. Beck
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Chevron USA Inc
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Individual
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Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of CA2683442A1 publication Critical patent/CA2683442A1/en
Application granted granted Critical
Publication of CA2683442C publication Critical patent/CA2683442C/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01VGEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V11/00Prospecting or detecting by methods combining techniques covered by two or more of main groups G01V1/00 - G01V9/00
    • G01V11/002Details, e.g. power supply systems for logging instruments, transmitting or recording data, specially adapted for well logging, also if the prospecting method is irrelevant
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21BEARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B47/00Survey of boreholes or wells
    • E21B47/12Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
    • E21B47/13Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling by electromagnetic energy, e.g. radio frequency

Abstract

Exemplary systems and methods are directed to transmission of electromagnetic (EM) pulses in a downhole environment, which is located below a surface of a landform. A sequence of EM energy pulses is generated from a signal generator located at the surface of the landform. The energy pulses are reflected at a ring frequency by one or more downhole transducers. The reflected energy pulse is received at a receiver, which is located at the surface, during a predetermined time interval. The receiver detects the received energy pulses through a time domain or frequency domain technique. The detected ring frequency is correlated to a parameter or condition of the downhole environment.

Claims (31)

What we claim is:
1. A method for interrogating a downhole environment below a surface of a landform, the method comprising the steps of:

directing at least one electromagnetic energy pulse into a downhole environment such that the electromagnetic energy pulse interacts with at least one downhole transducer such that at least some of the electromagnetic energy contained within the pulse is reflected at a ring frequency determined by the at least one downhole transducer;

receiving the reflected energy pulse at a receiver located at the surface of the landform during a predetermined time interval;

processing the received energy pulse to extract the ring frequency using a processing method selected from the group consisting of time domain tracking, frequency domain tracking, and combinations thereof; and correlating the ring frequency to a parameter of the transducer, wherein said parameter further correlates to a condition in the downhole environment.
2. The method of claim 1, wherein the processing is carried out using time domain tracking, and wherein the predetermined time interval is synchronized based on a depth-determined delay of the reflected energy pulse.
3. The method of claim 2, further comprising recording the ring frequency of the reflected energy pulse.
4. The method of claim 2, wherein the receiving step comprises controlling a gating of the receiver based on a delay preset.
5. The method of claim 2, wherein the receiving step comprises excluding low power signals that are equal or nearly equal to the ring frequency.
6. The method of claim 2, wherein the reflected energy pulses are generated at a frequency within a range of 10 MHz to 100KHz.
7. The method of claim 1, wherein the processing step is carried out using frequency domain tracking, and wherein the receiving step involves locking onto the ring frequency of the reflected energy pulse.
8. The method of claim 7, wherein the reflected energy pulses are generated at a frequency within a range of 10 MHz to 100KHz.
9 The method of claim 7, wherein the receiving step comprises controlling a gating of the receiver based on a depth determined delay of the reflected energy pulse.
The method of claim 7, wherein the locking step comprises comparing the ring frequency of the reflected energy pulse with a desired frequency.
11. The method of claim 10, wherein the ring frequency is locked when a result of the correlating is within a tolerance range.
12. The method of claim 7, wherein the receiver maintains the locked ring frequency when outside of the predetermined time interval.
13. The method of claim 7, wherein the receiving step comprises synchronizing the predetermined time interval with a depth determined delay of the reflected energy pulse.
14. The method of claim 7, wherein the correlating comprises addressing a look-up table based on a value of the locked ring frequency.
15. The method of claim 1, wherein the at least one downhole transducer comprises at least one inductive component and at least one capacitive component.
16. The method of claim 15, wherein the ring frequency of the at least one transducer is modulated by environmentally-induced changes to the capacitive component of said transducer.
17. The method of claim 1, wherein the step of processing the received energy pulse comprises a sub-step of digitizing information contained within the received energy pulse using algorithms that can enhance signal-to-noise.
18. The method of claim 1, further comprising a step of relaying information contained within the received energy pulse, as a signal, to a remote surface receiver.
19. A system for interrogating a downhole environment, which is located below a surface of a landform, based on at least one energy pulse that is reflected at a modulation frequency from at least one downhole transducer to the surface of the landform, the system comprising:

a means for receiving the modulated energy pulse at the surface during a predetermined time interval;

a means for processing the received energy pulse to extract the modulation frequency; and a means for correlating the modulation frequency of the energy pulse to a parameter of the transducer or a characteristic of the downhole environment.
20. The method of claim 19, wherein the at least one downhole transducer comprises at least one inductive and capacitive resonant structure.
21. The method of claim 20, wherein the at least one inductive structure isolates production tubing from casing in the downhole environment.
22. The system of claim 19, further comprising a means for controlling a gating of the receiving means based on a depth determined delay of the reflected energy pulse.
23. The system of claim 22, wherein the receiving means comprises a means for locking onto the modulation frequency of the energy pulse when the modulation frequency is within a threshold.
24. The system of claim 22, wherein the processing means is configured to exclude low power signals that are equal or nearly equal to the modulation frequency.
25. The system of claim 24, comprising a means for comparing the modulation frequency with a desired modulation frequency.
26. The system of claim 23, wherein the means for locking locks on the modulation frequency when a result produced by the comparing means is within a tolerance range.
27. The system of claim 19, said system comprising two or more downhole transducers having different resonant ring frequencies.
28. The system of claim 19, further comprising a means for actuating a device downhole, wherein said actuation is effected by an electromagnetic energy pulse that rings a transducer coupled to said device.
29. The system of claim 19, further comprising a directional wave coupler to minimize spurious signal reflections.
30. An apparatus for interrogating a downhole environment located below a surface of a landform, the apparatus being included in a system that transmits energy pulses to at least one downhole transducer which modulates the energy pulses and returns the modulated energy pulses to a location at the surface of the landform, the apparatus comprising:

a means for receiving the modulated energy pulses at the surface;
a means for sampling the modulated energy pulses;

a means for detecting a modulating frequency of the sampled energy pulses; and a means for correlating the modulating frequency to conditions of the downhole environment.
31. An apparatus for interrogating a downhole environment located below a surface of a landform, the apparatus being included in a system that transmits energy pulses to at least one downhole transducer which modulates the energy pulses and returns the modulated energy pulses to a location at the surface of the landform, the apparatus comprising:

a means for receiving the modulated energy pulses at the surface;

a means for locking onto a modulating frequency of the energy pulses when the modulating frequency is within a tolerance range; and a means for correlating the modulating frequency to conditions of the downhole environment.
CA2683442A 2007-04-13 2008-04-11 System and method for receiving and decoding electromagnetic transmissions within a well Expired - Fee Related CA2683442C (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US11/785,040 US8106791B2 (en) 2007-04-13 2007-04-13 System and method for receiving and decoding electromagnetic transmissions within a well
US11/785,040 2007-04-13
PCT/US2008/004730 WO2008127665A1 (en) 2007-04-13 2008-04-11 System and method for receiving and decoding electromagnetic transmissions within a well

Publications (2)

Publication Number Publication Date
CA2683442A1 true CA2683442A1 (en) 2008-10-23
CA2683442C CA2683442C (en) 2015-11-24

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CA2683442A Expired - Fee Related CA2683442C (en) 2007-04-13 2008-04-11 System and method for receiving and decoding electromagnetic transmissions within a well

Country Status (8)

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US (1) US8106791B2 (en)
EP (1) EP2137552A4 (en)
CN (1) CN101680958B (en)
AU (1) AU2008239642B2 (en)
BR (1) BRPI0810187B1 (en)
CA (1) CA2683442C (en)
EA (1) EA022795B1 (en)
WO (1) WO2008127665A1 (en)

Families Citing this family (38)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101529276B (en) 2006-09-08 2013-03-20 雪佛龙美国公司 A telemetry apparatus and method for monitoring a borehole
US7863907B2 (en) * 2007-02-06 2011-01-04 Chevron U.S.A. Inc. Temperature and pressure transducer
US7810993B2 (en) * 2007-02-06 2010-10-12 Chevron U.S.A. Inc. Temperature sensor having a rotational response to the environment
US7841234B2 (en) * 2007-07-30 2010-11-30 Chevron U.S.A. Inc. System and method for sensing pressure using an inductive element
US7636052B2 (en) 2007-12-21 2009-12-22 Chevron U.S.A. Inc. Apparatus and method for monitoring acoustic energy in a borehole
US9547104B2 (en) * 2007-09-04 2017-01-17 Chevron U.S.A. Inc. Downhole sensor interrogation employing coaxial cable
EP2350697B1 (en) * 2008-05-23 2021-06-30 Baker Hughes Ventures & Growth LLC Reliable downhole data transmission system
BRPI0918681B1 (en) * 2009-01-02 2019-06-25 Martin Scientific Llc SYSTEM OF TRANSMISSION OF SIGNAL OR ENERGY IN WELL HOLES
WO2011008123A2 (en) * 2009-07-17 2011-01-20 Baker Hughes Incorporated Radial waves in a borehole and stoneley waves for measuring formation permeability and electroacoustic constant
US8353677B2 (en) * 2009-10-05 2013-01-15 Chevron U.S.A. Inc. System and method for sensing a liquid level
US8575936B2 (en) 2009-11-30 2013-11-05 Chevron U.S.A. Inc. Packer fluid and system and method for remote sensing
US10488286B2 (en) * 2009-11-30 2019-11-26 Chevron U.S.A. Inc. System and method for measurement incorporating a crystal oscillator
BR112013011709B1 (en) * 2010-11-12 2020-10-06 Chevron U.S.A. Inc REMOTE SENSOR SYSTEM AND METHOD
US9103198B2 (en) * 2010-11-12 2015-08-11 Chevron U.S.A. Inc. System and method for remote sensing
GB2492947B (en) * 2011-06-27 2018-05-09 Expro North Sea Ltd Downhole signalling systems and methods
BR112014009959B1 (en) * 2011-10-25 2020-11-03 Jdi International Leasing Limited downhole signal transmission system and data communication method
US9515499B2 (en) 2011-11-03 2016-12-06 Fastcap Systems Corporation Production logging instrument
US9097101B2 (en) * 2012-03-29 2015-08-04 Chevron U.S.A Inc. System and method for measurement incorporating a crystal resonator
US9201156B2 (en) * 2012-03-29 2015-12-01 Chevron U.S.A. Inc. System and method for measurement incorporating a crystal resonator
US8857522B2 (en) 2012-11-29 2014-10-14 Chevron U.S.A., Inc. Electrically-powered surface-controlled subsurface safety valves
WO2014084889A1 (en) 2012-11-29 2014-06-05 Chevron U.S.A. Inc. Transmitting power within a wellbore
WO2014109754A1 (en) * 2013-01-11 2014-07-17 Halliburton Energy Services, Inc. Time-lapse time-domain reflectometry for tubing and formation monitoring
US9267334B2 (en) 2014-05-22 2016-02-23 Chevron U.S.A. Inc. Isolator sub
AU2014411408B2 (en) 2014-11-12 2018-05-10 Halliburton Energy Services, Inc. Well detection using induced magnetic fields
BR122020020284B1 (en) 2015-05-19 2023-03-28 Baker Hughes, A Ge Company, Llc METHOD FOR COLLECTING PROFILE DATA DURING MANEUVERING A DOWNWELL COMMUNICATION SYSTEM
WO2017007591A1 (en) 2015-07-06 2017-01-12 Martin Scientific, Llc Dipole antennas for wired-pipe systems
GB2540565B (en) * 2015-07-21 2019-04-24 Skf Ab Sensor assembly for bearing with wireless temperature sensor
WO2017014773A1 (en) * 2015-07-22 2017-01-26 Halliburton Energy Services, Inc. Electromagnetic monitoring with formation-matched resonant induction sensors
US10072494B2 (en) * 2015-11-24 2018-09-11 Chevron U.S.A. Inc. Remote sensing using transducer
US10705240B2 (en) 2017-05-11 2020-07-07 Saudi Arabian Oil Company Capacitive electromagnetic formation surveillance using passive source
AU2017420683A1 (en) * 2017-06-27 2019-11-21 Halliburton Energy Services, Inc. Methods and systems with estimated synchronization between modular downhole logging system modules
US10669817B2 (en) 2017-07-21 2020-06-02 The Charles Stark Draper Laboratory, Inc. Downhole sensor system using resonant source
US11136985B2 (en) 2018-08-31 2021-10-05 Baker Hughes, A Ge Company, Llc High frequency AC noise suppression within transformers
US11035972B2 (en) 2019-05-13 2021-06-15 Saudi Arabian Oil Company Systems and methods for electromagnetic waterfront surveillance in a vicinity of an oil well
US11346177B2 (en) 2019-12-04 2022-05-31 Saudi Arabian Oil Company Repairable seal assemblies for oil and gas applications
GB2606221A (en) * 2021-04-30 2022-11-02 Expro North Sea Ltd Well bore fluid sensor, system, and method
CN114856550B (en) * 2022-05-11 2023-04-04 西南石油大学 Device and method for accurately positioning petroleum casing pipe based on geomagnetic anomaly marker
CN116299724B (en) * 2023-05-22 2023-08-08 山东科技大学 Full-section overlying strata structure and separation layer frequency modulation periodic pulse type electromagnetic device and method

Family Cites Families (53)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3320579A (en) * 1966-04-11 1967-05-16 Frank R Abbott Compliant variable reluctance electroacoustic transducer
US3562741A (en) * 1967-04-05 1971-02-09 Burroughs Corp Electromagnetic pulse generating system
US4218507A (en) * 1975-01-13 1980-08-19 Graham Magnetics, Inc. Coated particles and process of preparing same
US4023136A (en) * 1975-06-09 1977-05-10 Sperry Rand Corporation Borehole telemetry system
US4160970A (en) * 1977-11-25 1979-07-10 Sperry Rand Corporation Electromagnetic wave telemetry system for transmitting downhole parameters to locations thereabove
US4308499A (en) * 1978-05-26 1981-12-29 Kali Und Salz A.G. Method utilizing electromagnetic wave pulses for determining the locations of boundary surfaces of underground mineral deposits
FR2520951A1 (en) * 1982-02-04 1983-08-05 Commissariat Energie Atomique ELECTROMAGNETIC PULSE GENERATOR OF HIGH VOLTAGE
CH673357A5 (en) * 1987-03-02 1990-02-28 Bbc Brown Boveri & Cie
US4839644A (en) * 1987-06-10 1989-06-13 Schlumberger Technology Corp. System and method for communicating signals in a cased borehole having tubing
NO163578C (en) 1987-10-23 1990-06-20 Saga Petroleum PROCEDURE AND DEVICE FOR TRANSFER OF TARGET DATA FROM A OIL BROWN TO THE SURFACE.
US5150067A (en) * 1990-04-16 1992-09-22 Mcmillan Michael R Electromagnetic pulse generator using an electron beam produced with an electron multiplier
DE4100365A1 (en) * 1991-01-04 1992-07-09 Mannesmann Ag STARTING LINE FOR CONTINUOUS CASTING PLANTS
DE69222207T2 (en) * 1991-03-13 1998-03-05 Westinghouse Electric Corp Method of determining the amount of deformation in a material in response to a compressive force
US5355714A (en) 1992-02-26 1994-10-18 Nippondenso Co., Ltd. Pressure sensor using a pressure responsive magnetic film to vary inductance of a coil
GB9212685D0 (en) * 1992-06-15 1992-07-29 Flight Refueling Ltd Data transfer
AU685132B2 (en) * 1993-06-04 1998-01-15 Gas Research Institute, Inc. Method and apparatus for communicating signals from encased borehole
US5467083A (en) * 1993-08-26 1995-11-14 Electric Power Research Institute Wireless downhole electromagnetic data transmission system and method
US5451873A (en) * 1993-10-05 1995-09-19 Schlumberger Technology Corporation Method and apparatus for determining the in situ larmor frequency of a wellbore NMR tool to compensate for accumulation of magnetic material on the magnet housing of the tool
US5686779A (en) * 1995-03-01 1997-11-11 The United States Of America As Represented By The Secretary Of The Army High sensitivity temperature sensor and sensor array
JPH10502767A (en) * 1995-04-28 1998-03-10 フィリップス エレクトロニクス ネムローゼ フェンノートシャップ Battery recharger
US5942991A (en) * 1995-06-06 1999-08-24 Diversified Technologies, Inc. Resonant sensor system and method
USH1744H (en) * 1995-09-21 1998-08-04 Clayton; Stanley R. Wireless remote sensing thermometer
US5852262A (en) * 1995-09-28 1998-12-22 Magnetic Pulse, Inc. Acoustic formation logging tool with improved transmitter
US6025725A (en) * 1996-12-05 2000-02-15 Massachusetts Institute Of Technology Electrically active resonant structures for wireless monitoring and control
US5821129A (en) * 1997-02-12 1998-10-13 Grimes; Craig A. Magnetochemical sensor and method for remote interrogation
US6234257B1 (en) * 1997-06-02 2001-05-22 Schlumberger Technology Corporation Deployable sensor apparatus and method
US6026913A (en) * 1997-09-30 2000-02-22 Halliburton Energy Services, Inc. Acoustic method of connecting boreholes for multi-lateral completion
US6393921B1 (en) * 1999-05-13 2002-05-28 University Of Kentucky Research Foundation Magnetoelastic sensing apparatus and method for remote pressure query of an environment
GB2386691B (en) 1999-06-22 2003-12-24 Axon Instr Ltd Ratio tool
US6633236B2 (en) * 2000-01-24 2003-10-14 Shell Oil Company Permanent downhole, wireless, two-way telemetry backbone using redundant repeaters
US7114561B2 (en) * 2000-01-24 2006-10-03 Shell Oil Company Wireless communication using well casing
US6670880B1 (en) * 2000-07-19 2003-12-30 Novatek Engineering, Inc. Downhole data transmission system
US6434372B1 (en) * 2001-01-12 2002-08-13 The Regents Of The University Of California Long-range, full-duplex, modulated-reflector cell phone for voice/data transmission
JP4164290B2 (en) 2002-05-20 2008-10-15 古野電気株式会社 Ultrasonic transceiver and scanning sonar
GB2396170B (en) * 2002-12-14 2007-06-06 Schlumberger Holdings System and method for wellbore communication
US7158049B2 (en) * 2003-03-24 2007-01-02 Schlumberger Technology Corporation Wireless communication circuit
GB2399921B (en) * 2003-03-26 2005-12-28 Schlumberger Holdings Borehole telemetry system
US7397388B2 (en) * 2003-03-26 2008-07-08 Schlumberger Technology Corporation Borehold telemetry system
US7234519B2 (en) * 2003-04-08 2007-06-26 Halliburton Energy Services, Inc. Flexible piezoelectric for downhole sensing, actuation and health monitoring
FR2854689B1 (en) * 2003-05-07 2005-09-02 Commissariat Energie Atomique DEVICE, SYSTEM AND METHOD FOR MEASURING MECHANICAL AND / OR THERMAL UNIAXIAL DEFORMATIONS USING A BRAGG NETWORK OPTICAL FIBER
US7537416B2 (en) * 2003-05-30 2009-05-26 Chevron Usa Inc Riser support system for use with an offshore platform
US7168487B2 (en) * 2003-06-02 2007-01-30 Schlumberger Technology Corporation Methods, apparatus, and systems for obtaining formation information utilizing sensors attached to a casing in a wellbore
WO2005050257A2 (en) * 2003-11-18 2005-06-02 Halliburton Energy Services, Inc. High temperature imaging device
US7256707B2 (en) 2004-06-18 2007-08-14 Los Alamos National Security, Llc RF transmission line and drill/pipe string switching technology for down-hole telemetry
US7180826B2 (en) * 2004-10-01 2007-02-20 Teledrill Inc. Measurement while drilling bi-directional pulser operating in a near laminar annular flow channel
US7548068B2 (en) * 2004-11-30 2009-06-16 Intelliserv International Holding, Ltd. System for testing properties of a network
GB2421449B (en) * 2004-12-21 2009-06-03 Daniel Stefanini Fluid treatment method and apparatus
US7256727B2 (en) * 2005-01-07 2007-08-14 Time Domain Corporation System and method for radiating RF waveforms using discontinues associated with a utility transmission line
US7454978B2 (en) 2005-11-16 2008-11-25 Delphi Technologies, Inc. Versatile strain sensor employing magnetostrictive electrical conductors
CN101529276B (en) * 2006-09-08 2013-03-20 雪佛龙美国公司 A telemetry apparatus and method for monitoring a borehole
US7583085B2 (en) * 2007-04-27 2009-09-01 Hall David R Downhole sensor assembly
US7530737B2 (en) * 2007-05-18 2009-05-12 Chevron U.S.A. Inc. System and method for measuring temperature using electromagnetic transmissions within a well
US7841234B2 (en) * 2007-07-30 2010-11-30 Chevron U.S.A. Inc. System and method for sensing pressure using an inductive element

Also Published As

Publication number Publication date
EP2137552A1 (en) 2009-12-30
US20080253230A1 (en) 2008-10-16
CN101680958B (en) 2013-05-01
WO2008127665A1 (en) 2008-10-23
BRPI0810187B1 (en) 2019-01-15
AU2008239642B2 (en) 2013-05-02
US8106791B2 (en) 2012-01-31
CA2683442C (en) 2015-11-24
BRPI0810187A2 (en) 2014-12-30
EA022795B1 (en) 2016-03-31
EA200970945A1 (en) 2010-04-30
EP2137552A4 (en) 2015-12-16
CN101680958A (en) 2010-03-24
AU2008239642A1 (en) 2008-10-23

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