Method for using logging device with down-hole transceiver for operation in extreme temperatures

• US 7,598,898 B1
• Filed: 09/13/2006
• Issued: 10/06/2009
• 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): Tarcza; Thomas H
• Assistant Examiner(s): GALT, CASSI J
• Application Number:
  US11/520,229
• Time in Patent Office: 1,119 Days
• Field of Search: 342/22, 342/54, 342/175, 342/195
• US Class Current: 342/22
• CPC Class Codes: G01S 13/885 for ground probing prospecting or detecting using electromagnetic waves G01V3/12
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• 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 method for radar logging down-hole in a wellbore of a subterranean formation without any down-hole cooling devices, the method comprising the steps of:

providing at least one radar source having at least one predetermined frequency;

providing at least one optical source having a predetermined wavelength;

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

providing at least one said modulated optical signal to a transmitter and receiver unit, wherein the transmitter and receiver unit comprises;

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

(b) at least one antenna in communication with at least one said photodiode; and

(c) a mixer in communication with at least one said photodiode and at least one said antenna; and

at least one said antenna receiving at least one said radio frequency source radar signal from at least one said photodiode, at least one said antenna transmitting at least one said radio frequency source radar signal into the formation, and at least one said antenna receiving a reflected radar signal; and

the mixer mixing the reflected radar signal with at least one said radio frequency source radar signal to provide an output, then utilizing the output to identify fracture geometry.

2. The method according to claim 1, wherein at least one said photodiode, the mixer and at least one said antenna are coupled by a hybrid coupler, wherein a twisted pair cable receives the output from the transmitter and receiver unit.

3. The method according to claim 1, wherein said at least one radar source is arranged above ground.

4. The method according to claim 1, wherein at least one said radar source, at least one said optical source and at least one said optical modulator are arranged below ground.

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

6. The method according to claim 1, wherein the mixer comprises a diode mixer that outputs an audio frequency.

7. The method according to claim 1, further comprising injecting a first portion of proppant through the wellbore into the subterranean formation and subsequently injecting a second portion into the subterranean formation such that the first portion of proppant travels to ends of fractures of the subterranean formation distal to the wellbore, wherein the first portion of proppant contains particles which are nonlinear and create new frequencies from the source radar signal and the second portion of proppant has an absence of said particles.

8. The method according to claim 1, further comprising injecting a first portion of proppant through the wellbore into the subterranean formation and subsequently injecting a second portion into the subterranean formation such that the first portion of proppant travels to ends of fractures of the subterranean formation distal to the wellbore, wherein the first portion of proppant contains particles which reflect or absorb the source radar signal and the second portion of proppant has an absence of said particles.

9. A method for logging in a wellbore of a subterranean formation, without any down-hole cooling devices, comprising the steps of:

(I) locating perforations in a wellbore casing and determining perforations where fractures have originated by;

(a) lowering a logging device comprising a gyroscope and a transmitter and a receiver unit for transmitting at least one first signal in the range of about 7 to 12 GHz into a well at a predetermined depth, wherein a series of perforated intervals are arranged in the wellbore casing;

(b) anchoring the logging device in place;

(c) scanning the wellbore casing for perforations with the at least one first signal;

(d) transmitting data from a reflected signal of the at least one first signal used to scan for perforations;

(e) determining which perforations are connected to a fracture of at least predetermined minimal length based on the data transmitted in step (d); and

(f) cutting a 10-15 cm narrow slot to dissect a perforation identified as connecting to the fracture, and

(II) determining aspects of fracture geometry by;

(a) generating a microwave radar signal;

(b) coupling the microwave radar signal to an IM laser to form a modulated laser signal and transmitting the modulated laser signal down-hole,

(c) utilizing a down-hole transceiver comprising a photodiode to convert the modulated laser signal to a radio frequency signal;

(d) splitting the radio frequency signal by sending a first Rf portion to an antenna and a second Rf portion to a diode mixer;

(e) transmitting an output from the antenna, through the perforations and into the fracture, and receiving back a reflected wave;

(f) mixing the reflected wave with the second Rf portion and generating an audio frequency signal having a beat frequency;

(g) transmitting the audio frequency signal, without amplification, to a receiver; and

(h) determining the fracture geometry aspects from the beat frequency.

10. The method according to claim 9, wherein step (I) further comprises the steps of:

(g) propagating at least one second signal in the range of about 0.5 to 2 GHz through the slot cut in step (f) and out into the connecting fracture; and

(h) transmitting back to the surface for analysis data concerning the returning signal waves of the at least one second signal.

11. The method according to claim 10, wherein the at least one first signal is approximately 10 GHz and the at least one second signal is approximately 1 GHz.

12. The method according to claim 10, wherein step (I) further comprises:

repeating steps (g) and (h) for each slot cut into the casing to develop a configuration of the size of the fracture.

13. The method according to claim 9, wherein the cutting in step (I)(f) is performed with a saw or laser that is integral with the logging device.

14. A method for logging in a wellbore of a subterranean formation, without any down-hole cooling devices, comprising the steps of:

(I) determining portions of a wellbore casing in contact with fractures of the subterranean formation by;

(a) transmitting a signal of a predetermined frequency into the subterranean formation through at least a portion of the casing adjacent to a fracture in the subterranean formation, the portion of casing being substantially transparent to the predetermined frequency;

(b) receiving a reflected signal reflected back from the subterranean formation through the portion of casing; and

(c) locating a position of the fracture based on a reflected signal, and

(II) determining aspects of fracture geometry by;

(a) generating a microwave radar signal;

(b) coupling the microwave radar signal to an IM laser to form a modulated laser signal and transmitting the modulated laser signal down-hole;

(c) utilizing a down-hole transceiver comprising a photodiode to convert the modulated laser signal to a radio frequency signal;

(d) splitting the radio frequency signal by sending a first Rf portion to an antenna and a second Rf portion to a diode mixer;

(e) transmitting an output from the antenna, through the perforations and into the fracture, and receiving back a reflected wave;

(f) mixing the reflected wave with the second Rf portion and generating an audio frequency signal having a beat frequency;

(g) transmitting the audio frequency signal, without amplification, to a receiver; and

(h) determining the fracture geometry aspects from the beat frequency.

15. The method according to claim 14, wherein step (I) further comprises:

(d) arranging composite pup-joints in the casing, the composite pup-joints being substantially transparent to the signal of the predetermined frequency and the reflected signal.

16. The method according to claim 15, wherein at least some of the composite pup-joints are above and below the position of the fracture determined in step (I)(c):

and wherein step (I) further comprises;

(e) transmitting the signal of the predetermined frequency through the composite pup-joints above and below the position of the fracture determined in step (c) to determine whether a top and a bottom of the fracture have been located, so as to provide a determination of the height of the fracture.

17. The method according to claim 14, wherein the portion of the casing, adjacent to the fracture in the subterranean formation and substantially transparent to the predetermined frequency, comprises composite material.

18. The method according to claim 17, wherein the composite material comprises fiberglass and epoxy resin.

19. The method according to claim 14, wherein the predetermined frequency is in the range of about 0.5 to 12 GHz.

20. A method for logging a wellbore to determine aspects of fracture geometry, in the absence of down-hole cooling devices, comprising the steps of:

(a) generating a microwave radar signal;

(b) coupling the microwave radar signal to an IM laser to form a modulated laser signal and transmitting the modulated laser signal down-hole;

(c) utilizing a down-hole transceiver comprising a photodiode to convert the modulated laser signal to a radio frequency signal;

(d) splitting the radio frequency signal by sending a first Rf portion to an antenna and a second Rf portion to a diode mixer;

(e) transmitting an output from the antenna into a fracture and receiving back a reflected wave;

(f) mixing the reflected wave with the second Rf portion and generating an audio frequency signal having a beat frequency;

(g) transmitting the audio frequency signal, without amplification, to a receiver; and

(h) determining the fracture geometry aspects from the beat frequency.