US 7,598,898 B1Granted

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

AssigneeHexion Specialty Chemicals, Inc.

InventorsEric E. Funk, Ethan A. Funk, Michael L. Sheriff, Scott M. McCarthy, Robert R. McDaniel

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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.

Claims20

Dependent claims

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.

9 more elements

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.

15 more elements

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.

12 more elements

Dependencies are inferred from the claim text.