Logging device with down-hole transceiver for operation in extreme temperatures

• US 7,450,053 B2
• Filed: 09/13/2006
• Issued: 11/11/2008
• Est. Priority Date: 09/13/2006
• Status: Active Grant

• Current Assignee: Hexion Incorporated (Hexion Intermediate Holding 2, Inc.)
• Original Assignee: Hexion Specialty Chemicals, Inc. (Bakelite UK TopCo Ltd.)
• Inventors: McDaniel, Robert R., Funk, Ethan A., Sheriff, Michael L., Funk, Eric E., McCarthy, Scott M.
• Primary Examiner(s): Gregory; Bernarr E
• Application Number:
  US11/520,234
• Publication Number:
  US 20080062036A1
• Time in Patent Office: 790 Days
• Field of Search: 342/21, 342/22, 342/27, 342/28, 342 52- 59, 342/175, 342/195, 324323-375, 340/853.1, 340/854.6, 340/854.7, 340/870.01, 340/870.28, 340/870.29, 340/854.3
• US Class Current: 342/22
• CPC Class Codes: E21B 29/06 Cutting windows, e.g. directional window cutters for whipstock operations E21B29/005 and E21B29/08 take precedence
• CPC Class Codes: E21B 43/267 reinforcing fractures by propping
• CPC Class Codes: E21B 49/00 Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
• CPC Class Codes: G01S 13/88 Radar or analogous systems specially adapted for specific applications electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00
• CPC Class Codes: G01S 13/885 for ground probing prospecting or detecting using electromagnetic waves G01V3/12
• CPC Class Codes: G01V 3/30 operating with electromagnetic waves

Abstract

A logging radar system and method for measuring propped fractures and down-hole formation conditions in a subterranean formation including: a radar source; an optical source; an optical modulator for modulating an optical signal from the optical source according to a signal from the radar source; a photodiode for converting the modulated optical signal output from the optical modulator to the source radar signal; a transmitter and receiver unit; and a mixer. The transmitter and receiver unit receives the source radar signal from the photodiode, transmits the source radar signal into the formation and receives a reflected radar signal. The mixer mixes the reflected radar signal with the source radar signal to provide an output. This technology can be used to describe all fractures connected to the wellbore and differentiate between the dimensions of the two vertical wings of a propped fracture.

Claims

1. A logging radar system for measuring propped fractures and down-hole formation conditions in a subterranean formation by a logging device, comprising:

at least one radar source for generation of at least one source radar signal;

at least one optical source;

at least one optical modulator in communication with at least one said radar source and at least one said optical source for modulating at least one optical signal according to at least one said source radar signal having at least one predetermined frequency;

at least one photodiode for converting the modulated optical signal output from at least one said optical modulator to at least one said source radar signal;

at least one transmitter and receiver unit comprising;

(a) at least one antenna communicating with at least one said photodiode, for receiving at least one said source radar signal from at least one said photodiode and transmitting at least one said source radar signal into the subterranean formation and receiving a reflected radar signal; and

(b) a mixer, in communication with at least one said photodiode and at least one said antenna, for mixing the reflected radar signal with at least one said source radar signal to provide an output.

2. The system according to claim 1, wherein at least one said photodiode is adapted and configured for arrangement down-hole in a wellbore.

3. The system according to claim 1, wherein at least one said transmitter and receiver unit is adapted and configured for arrangement down-hole in a wellbore.

4. The system according to claim 1, wherein at least one said photodiode, the mixer and at least one said antenna are coupled by a hybrid coupler.

5. The system according to claim 4, further comprising a device for cutting openings in a wellbore casing in the subterranean formation.

6. The system according to claim 1, wherein the mixer comprises a diode mixer and the output of the diode mixer is an audio frequency output.

7. The system according to claim 6, wherein the audio frequency output of the diode mixer comprises a beat frequency based on a difference in RF frequency between the source radar signal and the reflected radar signal.

8. The system according to claim 7, further comprising an audio receiver for receiving the beat frequency of the diode mixer, a twisted pair of wires for transmitting the audio frequency output.

9. The system according to claim 6, wherein the transmitter and receiver unit lacks an amplifier to amplify the audio frequency output of the diode mixer.

10. The system according to claim 6, comprising at least one fiber optical cable capable of withstanding temperatures greater than 200°

C. for transmitting at least one modulated optical signal to at least one said transmitter and receiver unit.

11. The system according to claim 10, wherein at least one fiber optical cable comprises a polyimide coated fiber.

12. The system according to claim 11, wherein the audio frequency output of the diode mixer is adapted to be transmitted over a wire cable.

13. The system according to claim 1, wherein at least one said source radar signal is encoded, and the mixer comprises a correlator that cross-correlates the encoded source radar signal with the reflected radar signal.

14. The system according to claim 1, further comprising a gyroscope for determining logging device direction, positioning and for determining fracture azimuth.

15. The system according to claim 1, comprising more than one said photodiode and more than one said transmitter and receiver unit.

16. The system according to claim 1, wherein said at least one said photodiode comprises a first photodiode and a second photodiode, said transmitter and receiver unit comprises a first transceiver for transmitting a first frequency, and said system further comprises a second transceiver for transmitting a second frequency, the second transceiver in communication with the second photodiode,

wherein said first frequency and said second frequency are different,

wherein the first frequency is for determining at least a fracture length from the wellbore, and

wherein the second frequency is for assisting with orientating the antenna of the first transceiver at casing openings connected to the propped fracture and for assisting with orienting the second transceiver to detect a direction of the propped fracture.

17. The system according to claim 16, further comprising a gyroscope for orienting at least one of said first transceiver and said second transceiver down-hole.

18. The system according to claim 17, further comprising one of a vertical saw and a laser for cutting vertical slots in the wellbore casing.

19. The system according to claim 16, wherein the mixer comprises a single balanced diode mixer, and wherein the first frequency is in the range of 1 GHz ±

0.1 GHz and the second frequency is in the range of 10 GHz ±

1 GHz.

20. The system according to claim 16, comprising at least one fiber optical cable capable of withstanding temperatures greater than 200°

C. for transmitting at least one modulated optical signal to the first transceiver and the second transceiver.

21. The system according to claim 1, wherein at least one said optical modulator comprises a Mach Zehnder Modulator.

22. The system according to claim 1, wherein the transmitter and receiver unit is operable down-hole of a well at a temperature of about 200°

C. without any cooling apparatus.

23. The system according to claim 1 wherein the at least one transmitter and receiver unit comprises a transceiver adapted for arrangement down-hole in the wellbore, the transceiver comprising:

(a) an antenna communicating with the photodiode, for receiving the source radar signal from the photodiode and transmitting the source radar signal into the subterranean formation and receiving a reflected radar signal; and

(b) a mixer, in communication with the photodiode and the antenna, for mixing the reflected radar signal with the source radar signal to provide an output.

24. A logging radar system for measuring propped fractures and down-hole formation conditions in a subterranean formation by a logging device, comprising:

a first radar source for generation of a first source radar signal;

an optical source;

an optical modulator in communication with the first radar source and the optical source for modulating an optical signal according to the first source radar signal having a predetermined frequency;

a transmitter photodiode, for arrangement down-hole in a wellbore, for converting the modulated optical signal output from the optical modulator to the source radar signal;

a transmitter adapted for arrangement down-hole in the wellbore, the transmitter comprising;

a transmitter antenna communicating with the photodiode, for receiving the source radar signal from the photodiode and transmitting the source radar signal into the subterranean formation; and

a receiver photodiode for arrangement down-hole in the wellbore;

a receiver adapted for arrangement down-hole in the wellbore, the receiver comprising a receiver antenna for receiving a reflected radar signal, a mixer, in communication with the receiver photodiode and the receiver antenna, for mixing the reflected radar signal with a second source radar signal to provide an output based on a difference in the second source radar signal and the reflected radar signal;

wherein the receiver photodiode, mixer and receiver antenna are coupled,

wherein the transmitter antenna and the receiver antenna are the same antenna or different antennas, wherein the receiver photodiode and the transmitter photodiode are the same photodiode or different photodiodes, wherein the first source radar signal and the second source radar signal are the same source radar signal or different source radar signals.

25. An apparatus for arrangement down-hole in a wellbore of a subterranean formation, comprising:

(a) at least one photodiode for converting at least one modulated optical signal output from at least one optical modulator to at least one source radar signal;

(b) at least one antenna communicating with at least one said photodiode for receiving at least one said source radar signal for transmission into the subterranean formation and receiving a reflected radar signal; and

(c) a diode mixer in communication with at least one said photodiode and at least one said antenna for mixing the reflected radar signal with at least one said source radar signal to provide an audio frequency output.

26. The apparatus according to claim 25, wherein at least one said photodiode, the diode mixer and at least one said antenna are coupled by a hybrid coupler.

27. The apparatus according to claim 25, wherein the apparatus is capable of operating in temperatures exceeding 200°

C. without any cooling apparatus, and has no amplifier for amplifying the output of the diode mixer.

28. The apparatus according to claim 25, comprising a twisted pair cable for transmitting the audio frequency output from the diode mixer without amplification.