US3747702A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cement evaluation logging utilizing reflection coefficients
Assignee: Schlumberger Technology Corp
•
Filing: 1970-05-25
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Granted: 1973-07-24
•
Expires: 1990-05-25
Abstract
Abstract In accordance with principles of the present invention, methods and apparatus are provided for evaluating the cement effectiveness in cased boreholes. Acoustic energy is used to excite the borehole-casing-annulus-formation system and the radial transfer of energy into the formation is determined by examining the reflection coefficients of the system in a plurality of relatively wide frequency bands over the spectrum of the acoustic energy used to excite the system. The spectrum analysis is carried out by passing electrical signals representative of the reflected acoustic energy through a plurality of relatively wide bandpass filters whose center frequencies are selected according to the size of the casing being logged. A relatively low magnitude of the reflection coefficient in a majority of these filters is indicative of a good cement condition.
Inventors
- 👤 R Beil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:45
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/40; G01V1/44; E; E21; E21B; E21B47/00; E21B47/005
Claims Analysis
Total Claims: 59
Claim 1
Independent Claim
108 words
A method for determining the cement effectiveness in a cased and cemented well bore comprising the steps of: transmitting acoustic energy from the well bore into the casing and formations; receiving a reflected portion of the transmitted acoustic energy and generating electrical signals representative thereof; applying each of said representative electrical signals to at least three relatively wide bandpass frequency filters each having different center frequencies spaced over a frequency spectrum of the received acoustic energy for obtaining filtered output signals; and selecting at least two of the filtered output signals having the lowest magnitudes from said plurality of bandpass filters for a determation of the cement effectiveness.
Claim 2
Independent Claim
108 words
A method for determining the cement effectiveness in a cased and cemented well bore comprising the steps of: transmitting acoustic energy from the well bore into the casing and formations; receiving a reflected portion of the transmitted acoustic energy and generating electrical signals representative thereof; applying each of said representative electrical signals to at least three relatively wide bandpass frequency filters each having different center frequencies spaced over a frequency spectrum of the received acoustic energy for obtaining filtered output signals; and selecting at least two of the filtered output signals having the lowest magnitudes from said plurality of bandpass filters for a determation of the cement effectiveness.
Claim 3
Dependent Claim
68 words
The method of claim 1 and further including the steps of: generating a signal representative of the average value of said selected filtered output signals having the lowest magnitudes; and recording as a function of borehole depth said signal representatative of the average value of said selected filtered output signals, the recording so produced being indicative of cement effectiveness as a function of depth in the well bore.
Claim 4
Independent Claim
109 words
A method of processing electrical signals representative of radially reflected acoustic energy received in a cased borehole to evaluate cement effectiveness comprising the steps of: applying said representative electrical signals to at least three relatively wide bandpass frequency filters having different center frequencies spaced over a frequency spectrum of the received acoustic energy; integrating the output signals of said filters to generate signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passbands; and generating signals representative of the average of at least two of the reflection coefficient signals having the lowest magnitudes said average signal being indicative of the cement effectiveness.
Claim 5
Independent Claim
109 words
A method of processing electrical signals representative of radially reflected acoustic energy received in a cased borehole to evaluate cement effectiveness comprising the steps of: applying said representative electrical signals to at least three relatively wide bandpass frequency filters having different center frequencies spaced over a frequency spectrum of the received acoustic energy; integrating the output signals of said filters to generate signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passbands; and generating signals representative of the average of at least two of the reflection coefficient signals having the lowest magnitudes said average signal being indicative of the cement effectiveness.
Claim 6
Dependent Claim
21 words
The method of claim 3 and further including the step of recording said average signal as a function of borehole depth.
Claim 7
Dependent Claim
35 words
The method of claim 3 and further including the step of recording at least two of the signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passbands.
Claim 8
Independent Claim
172 words
A method of logging a cased well borehole to determine the effectiveness of cement disposed in the annulus between the casing and the formations comprising the steps of: moving an acoustic logging tool having at least one acoustic transmitter and at least one acoustic receiver through the borehole; transmitting a component of acoustic energy radially outwardly from said transmitter into the casing and formations; receiving a reflected portion of said transmitted acoustic energy and generating electrical signals representative thereof; passing each of said representative signals through at least three relatively wide bandpass frequency filters having different center frequencies spaced over the frequency spectrum of the received acoustic energy to obtain a filtered output signal; integrating the filtered output signals of each of said filters to generate signals representative of the magnitude of the acoustic reflection coefficient in the frequency regions of the filter passbands; and generating a signal representative of the average of at least two of the lowest magnitude reflection coefficient signals, said average signal being indicative of the cement effectiveness.
Claim 9
Independent Claim
172 words
A method of logging a cased well borehole to determine the effectiveness of cement disposed in the annulus between the casing and the formations comprising the steps of: moving an acoustic logging tool having at least one acoustic transmitter and at least one acoustic receiver through the borehole; transmitting a component of acoustic energy radially outwardly from said transmitter into the casing and formations; receiving a reflected portion of said transmitted acoustic energy and generating electrical signals representative thereof; passing each of said representative signals through at least three relatively wide bandpass frequency filters having different center frequencies spaced over the frequency spectrum of the received acoustic energy to obtain a filtered output signal; integrating the filtered output signals of each of said filters to generate signals representative of the magnitude of the acoustic reflection coefficient in the frequency regions of the filter passbands; and generating a signal representative of the average of at least two of the lowest magnitude reflection coefficient signals, said average signal being indicative of the cement effectiveness.
Claim 10
Dependent Claim
41 words
The method of claim 6 wherein the steps of transmitting and receiving acoustic energy in the borehole are performed repetitively as said logging tool moves through the borehole and the remaining signal processing steps are performed repetitively with such transmitter firing.
Claim 11
Dependent Claim
32 words
The method of claim 6 and further including the step of recording as a function of borehole depth said signal representative of the average of the two lowest magnitude reflection coefficient signals.
Claim 12
Dependent Claim
39 words
The method of claim 8 and further including the step of recording as a function of borehole depth said signals representative of the magnitude of the acoustic reflection coefficients in the frequency region of each of the filter passbands.
Claim 13
Dependent Claim
39 words
The method of claim 6 and further including the step of recording as a function of borehole depth said signals representative of the magnitude of the acoustic reflection coefficients in the frequency region of each of the filter passbands.
Claim 14
Dependent Claim
51 words
The method of claim 6 wherein the step of passing said representative signals through said relatively wide bandpass frequency filters having different center frequencies is performed by passing said signals through three such filters having different bandwidths and different center frequencies spaced over the frequency spectrum of the received acoustic energy.
Claim 15
Dependent Claim
41 words
The method of claim 11 and further including the step of recording as a function of borehole depth said signal representative of the average of the two lowest magnitude reflection coefficient signals, said average signal being indicative of the cement effectiveness.
Claim 16
Dependent Claim
39 words
The method of claim 12 and further including the step of recording as a function of borehole depth said three signals representative of the magnitude of the acoustic reflection coefficient in the frequency regions of the three filter passbands.
Claim 17
Dependent Claim
103 words
Apparatus for determining the cement effectiveness in a cased well bore comprising: transducer means for transmitting a component of acoustic energy radially outward from the well bore into the casing and formations and for receiving a reflected portion of the transmitted acoustic energy and generating electrical signals representative thereof; at least three relatively wide bandpass frequency filters coupled to said transducer means, said filters and having different center frequencies spaced over a frequency spectrum of the received acoustic energy; and means coupled to said filters for processing said signals to obtain at least the two lowest magnitude output signals of said bandpass filters.
Claim 18
Dependent Claim
103 words
Apparatus for determining the cement effectiveness in a cased well bore comprising: transducer means for transmitting a component of acoustic energy radially outward from the well bore into the casing and formations and for receiving a reflected portion of the transmitted acoustic energy and generating electrical signals representative thereof; at least three relatively wide bandpass frequency filters coupled to said transducer means, said filters and having different center frequencies spaced over a frequency spectrum of the received acoustic energy; and means coupled to said filters for processing said signals to obtain at least the two lowest magnitude output signals of said bandpass filters.
Claim 19
Dependent Claim
69 words
The apparatus of claim 14 and further including: means coupled to said processing means for generating a signal representative of the average value of said lowest magnitude signals; and means for recording as a function of borehole depth said signals representative of the average value of said lowest magnitude signals, whereby the recording so produced is indicative of cement effectiveness as a function of depth in the well bore.
Claim 20
Dependent Claim
102 words
Apparatus for processing electrical signals representative of radially reflected acoustic energy received in a cased borehole to evaluate cementing effectiveness comprising: at least three relatively wide bandpass frequency filters having different center frequencies spaced over a frequency spectrum of the received acoustic energy for receiving such representative electrical signals; means for integrating the output signals of said filters to generate signals representative of the magnitude of thE acoustic reflection coefficient in the frequency region of the filter passbands; and means for generating an electrical signal representative of the average of at least two of the reflection coefficient signals having the lowest magnitudes.
Claim 21
Dependent Claim
102 words
Apparatus for processing electrical signals representative of radially reflected acoustic energy received in a cased borehole to evaluate cementing effectiveness comprising: at least three relatively wide bandpass frequency filters having different center frequencies spaced over a frequency spectrum of the received acoustic energy for receiving such representative electrical signals; means for integrating the output signals of said filters to generate signals representative of the magnitude of thE acoustic reflection coefficient in the frequency region of the filter passbands; and means for generating an electrical signal representative of the average of at least two of the reflection coefficient signals having the lowest magnitudes.
Claim 22
Dependent Claim
27 words
The apparatus of claim 16 and further including: recording means coupled to said average generating means for recording said average signal as a function of borehole depth.
Claim 23
Dependent Claim
34 words
The apparatus of claim 16 and further including means for recording at least two of the signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passbands.
Claim 24
Dependent Claim
186 words
Apparatus for logging a cased well borehole to determine the effectiveness of cement disposed in the annulus between the casing and the formations comprising: an acoustic logging tool having at least one acoustic transmitter and at least one acoustic receiver; means for moving said acoustic logging tool through different depths in the borehole; means for repetit-ively firing said acoustic transmitter to transmit acoustic energy radially outwardly from said logging tool into the casing and formations; means for repetitively activating said acoustic receiver in response to said transmitter firing to receive a reflected portion of the transmitted acoustic energy and generate electrical signals representative thereof; at least three relatively wide bandpass frequency filters having different center frequencies spaced over a frequency spectrum of the received acoustic energy; means for passing said representative signals through said bandpass frequency filters; means for integrating the output signals of each of said frequency filters to generate signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passbands; and means for generating a signal representative of the majority of the lowest magnitude reflection coefficient signals.
Claim 25
Dependent Claim
186 words
Apparatus for logging a cased well borehole to determine the effectiveness of cement disposed in the annulus between the casing and the formations comprising: an acoustic logging tool having at least one acoustic transmitter and at least one acoustic receiver; means for moving said acoustic logging tool through different depths in the borehole; means for repetit-ively firing said acoustic transmitter to transmit acoustic energy radially outwardly from said logging tool into the casing and formations; means for repetitively activating said acoustic receiver in response to said transmitter firing to receive a reflected portion of the transmitted acoustic energy and generate electrical signals representative thereof; at least three relatively wide bandpass frequency filters having different center frequencies spaced over a frequency spectrum of the received acoustic energy; means for passing said representative signals through said bandpass frequency filters; means for integrating the output signals of each of said frequency filters to generate signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passbands; and means for generating a signal representative of the majority of the lowest magnitude reflection coefficient signals.
Claim 26
Dependent Claim
31 words
The apparatus of claim 19 and further including: means for generating a signal representative of the average of the two of said reflection coefficient signals having most nearly the same magnitude.
Claim 27
Dependent Claim
38 words
The apparatus of claim 19 and further including: means for recording as a function of borehole depth said signals representative of the magnitude of the acoustic reflection coefficients in the frequency region of each of the filter passbands.
Claim 28
Dependent Claim
49 words
The apparatus of claim 19 and further including: means for simultaneously recording as a function of borehole depth both said signals representative of the reflection coefficients in the frequency region of the filter passbands and said signal representative of the average of the two lowest such reflection coefficient signals.
Claim 29
Dependent Claim
33 words
The apparatus of claim 19 wherein said frequency filters comprise three relatively wide bandpass frequency filters having different bandwidths and different center frequencies spaced over a frequency spectrum of the received acoustic energy.
Claim 30
Independent Claim
215 words
A method of acoustically logging a cased well borehole to determine the effectiveness of cement disposed in the annulus between the casing and the formations, comprising the steps of: moving an acoustic logging tool having at least one acoustic transmitter and at least one acoustic receiver longitudinally spaced from said transmitter through the borehole; repetitively transmitting acoustic energy from said transmitter into the casing and surrounding formations; repetitively receiving in response to the acoustic transmission a reflected portion of said transmitted acoustic energy and generating electrical signals representative thereof; passing said representative signals through three relatively wide bandpass frequency filters having different center frequencies spaced over the frequency spectrum of the received acoustic energy; integrating the output signals of each of said filters to generate signals representative of the magnitude of tHe acoustic reflection coefficient in the frequency region of the filter passbands; generating a signal representative of the average of the two lowest magnitude reflection coefficient signals, said average signal being indicative of the cementing effectiveness in the borehole; simultaneously with the above steps measuring the acoustic travel time of the transmitted acoustic signal between said longitudinally spaced transmitter and receiver and generating a signal representative thereof; and recording as a function of borehole depth said acoustic travel time signal and said average signal.
Claim 31
Independent Claim
215 words
A method of acoustically logging a cased well borehole to determine the effectiveness of cement disposed in the annulus between the casing and the formations, comprising the steps of: moving an acoustic logging tool having at least one acoustic transmitter and at least one acoustic receiver longitudinally spaced from said transmitter through the borehole; repetitively transmitting acoustic energy from said transmitter into the casing and surrounding formations; repetitively receiving in response to the acoustic transmission a reflected portion of said transmitted acoustic energy and generating electrical signals representative thereof; passing said representative signals through three relatively wide bandpass frequency filters having different center frequencies spaced over the frequency spectrum of the received acoustic energy; integrating the output signals of each of said filters to generate signals representative of the magnitude of tHe acoustic reflection coefficient in the frequency region of the filter passbands; generating a signal representative of the average of the two lowest magnitude reflection coefficient signals, said average signal being indicative of the cementing effectiveness in the borehole; simultaneously with the above steps measuring the acoustic travel time of the transmitted acoustic signal between said longitudinally spaced transmitter and receiver and generating a signal representative thereof; and recording as a function of borehole depth said acoustic travel time signal and said average signal.
Claim 32
Dependent Claim
18 words
The method of claim 24 and further including the step of simultaneously recording said acoustic reflection coefficient signals.
Claim 33
Independent Claim
277 words
A method of acoustically logging a cased well borehole to determine the effectiveness of cement disposed in the annulus between the casing and the formations, comprisign the steps of; moving an acoustic logging tool having at least one acoustic transmitter and at least one acoustic receiver longitudinally spaced from said transmitter through the borehole; repetitively transmitting acoustic energy from said transmitter into the casing and surrounding formations; repetitively receiving in response to the acoustic transmission a reflected portion of said transmitted acoustic energy and generating electrical signals representative thereof; passing said representative signals through three relatively wide bandpass frequency filters having different center frequencies spaced over the frequency spectrum of the received acoustic energy; integrating the output signals of each of said filters to generate signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passband; generating a signal representative of the average of the two lowest magnitude reflection coefficient signals, said average signal being indicative of the cementing effectiveness in the borehole; simultaneously with the above steps measuring the acoustic travel time of the transmitted acoustic signal between said longitudinally spaced transmitter and receiver and generating a signal representative thereof; recording as a function of borehole depth said acoustic travel time signal and said average signal; simultaneously with the above steps measuring the amplitude of the early arriving acoustic signal and generating a signal representative thereof, said signal being indicative of the contact of the cement disposed in the annulus with the exterior surface of the well casing; and recording as a function of borehole depth said cement contact signal, said acoustic travel time signal and said average signal.
Claim 34
Independent Claim
277 words
A method of acoustically logging a cased well borehole to determine the effectiveness of cement disposed in the annulus between the casing and the formations, comprisign the steps of; moving an acoustic logging tool having at least one acoustic transmitter and at least one acoustic receiver longitudinally spaced from said transmitter through the borehole; repetitively transmitting acoustic energy from said transmitter into the casing and surrounding formations; repetitively receiving in response to the acoustic transmission a reflected portion of said transmitted acoustic energy and generating electrical signals representative thereof; passing said representative signals through three relatively wide bandpass frequency filters having different center frequencies spaced over the frequency spectrum of the received acoustic energy; integrating the output signals of each of said filters to generate signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passband; generating a signal representative of the average of the two lowest magnitude reflection coefficient signals, said average signal being indicative of the cementing effectiveness in the borehole; simultaneously with the above steps measuring the acoustic travel time of the transmitted acoustic signal between said longitudinally spaced transmitter and receiver and generating a signal representative thereof; recording as a function of borehole depth said acoustic travel time signal and said average signal; simultaneously with the above steps measuring the amplitude of the early arriving acoustic signal and generating a signal representative thereof, said signal being indicative of the contact of the cement disposed in the annulus with the exterior surface of the well casing; and recording as a function of borehole depth said cement contact signal, said acoustic travel time signal and said average signal.
Claim 35
Independent Claim
98 words
A method for determining the cement effectiveness in a cased and cemented well bore comprising the steps of: transmitting acoustic energy from the well bore into the casing and formations; receiving a reflected portion of the transmitted acoustic energy and generating signals representative thereof; applying said representative signals to at least three relatively wide bandpass frequency filters each having different center frequencies spaced over a frequency spectrum of acoustic energy for obtaining filtered output signals; and selecting at least two of the filtered output signals having most nearly the same magnitudes for a determination of the cement effectiveness.
Claim 36
Independent Claim
98 words
A method for determining the cement effectiveness in a cased and cemented well bore comprising the steps of: transmitting acoustic energy from the well bore into the casing and formations; receiving a reflected portion of the transmitted acoustic energy and generating signals representative thereof; applying said representative signals to at least three relatively wide bandpass frequency filters each having different center frequencies spaced over a frequency spectrum of acoustic energy for obtaining filtered output signals; and selecting at least two of the filtered output signals having most nearly the same magnitudes for a determination of the cement effectiveness.
Claim 37
Dependent Claim
46 words
The method of claim 27 and further including the steps of: generating a signal representative of the average value of the selected filtered output signals; and recording as a function of borehole depth said signal representative of the average value of said selected filtered output signals.
Claim 38
Independent Claim
108 words
A method of processing electrical signals representative of radially reflected acoustic energy received in a cased borehole to evaluate cement effectiveness comprising the steps of: applying said representative signals to at least three relatively wide bandpass fRequency filters having different center frequencies spaced over a frequency spectrum of acoustic energy; integrating the output signals of said filters to generate signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passbands; and generating signals representative of the average of at least two of the reflection coefficient signals having most nearly the same magnitudes, said average signal being indicative of the cement effectiveness.
Claim 39
Independent Claim
108 words
A method of processing electrical signals representative of radially reflected acoustic energy received in a cased borehole to evaluate cement effectiveness comprising the steps of: applying said representative signals to at least three relatively wide bandpass fRequency filters having different center frequencies spaced over a frequency spectrum of acoustic energy; integrating the output signals of said filters to generate signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passbands; and generating signals representative of the average of at least two of the reflection coefficient signals having most nearly the same magnitudes, said average signal being indicative of the cement effectiveness.
Claim 40
Dependent Claim
21 words
The method of claim 29 and further including the step of recording said average signal as a function of borehole depth.
Claim 41
Dependent Claim
35 words
The method of claim 29 and further including the step of recording at least two of the signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passbands.
Claim 42
Independent Claim
148 words
A method of logging a cased well borehole to determine the effectiveness of cement disposed in the annulus between the casing and the formations comprising the steps of: moving an acoustic logging tool having at least one acoustic trasnmitter and at least one acoustic receiver through the borehole; transmitting a component of acoustic energy radially outwardly from said transmitter into the casing and formations; receiving a reflected portion of said transmitted acoustic energy and generating electrical signals representative thereof; passing said representative signals through at least three relatively wide bandpass frequency filters having different center frequencies spaced over the acoustic frequency spectrum to obtain filtered output signals; integrating said filtered output signals to generate signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passbands; and generating a signal representative of the average of at least two selected reflection coefficient signals.
Claim 43
Independent Claim
148 words
A method of logging a cased well borehole to determine the effectiveness of cement disposed in the annulus between the casing and the formations comprising the steps of: moving an acoustic logging tool having at least one acoustic trasnmitter and at least one acoustic receiver through the borehole; transmitting a component of acoustic energy radially outwardly from said transmitter into the casing and formations; receiving a reflected portion of said transmitted acoustic energy and generating electrical signals representative thereof; passing said representative signals through at least three relatively wide bandpass frequency filters having different center frequencies spaced over the acoustic frequency spectrum to obtain filtered output signals; integrating said filtered output signals to generate signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passbands; and generating a signal representative of the average of at least two selected reflection coefficient signals.
Claim 44
Dependent Claim
43 words
The method of claim 32 wherein the step of generating a signal representative of the average of at least two selected reflection coefficient signals comprises generating such a signal representative of the two reflection coefficient signals whose magnitude are most nearly the same.
Claim 45
Dependent Claim
22 words
The method of claim 33 and further including the step of recording said average representative signal as a function of borehole depth.
Claim 46
Dependent Claim
23 words
The method of claim 34 and further including the step of recording said acoustic reflection coefficient signals as a function of borehole depth.
Claim 47
Dependent Claim
101 words
Apparatus for processing electrical signals representative of radially reflected acoustic energy received in a cased borehole to evaluate cement effectiveness comprising: at least three relatively wide bandpass frequency filters having different center frequencies spaced over the acoustic frequency spectrum; means for applying said repre-sentative signals to said filters; means responsive to the outputs of said filters for generating signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passbands; and means for generating a signal representative of the average of at least two of the reflection coefficients signals having most nearly the same magnitudes.
Claim 48
Dependent Claim
101 words
Apparatus for processing electrical signals representative of radially reflected acoustic energy received in a cased borehole to evaluate cement effectiveness comprising: at least three relatively wide bandpass frequency filters having different center frequencies spaced over the acoustic frequency spectrum; means for applying said repre-sentative signals to said filters; means responsive to the outputs of said filters for generating signals representative of the magnitude of the acoustic reflection coefficient in the frequency region of the filter passbands; and means for generating a signal representative of the average of at least two of the reflection coefficients signals having most nearly the same magnitudes.
Claim 49
Dependent Claim
27 words
The apparatus of claim 36 and further including: recording means coupled to said average generating means for recording said average signal as a function of borehole depth.
Claim 50
Independent Claim
126 words
A method of logging a cased well borehole to determine the effectiveness of cement disposed in the annulus between the casing and the formations comprising the steps of: transmitting a component of acoustic energy radially outwardly from the borehole into the casing and surrounding formations; receiving a reflected portion of said transmitted energy and generating electrical signals representative thereof; separating the signal representative of the received energy into its acoustic frequency spectrum components; selecting at least three of said frequenCy spectrum components over at least three different, relatively wide, bandwidths and generating signals functionally related to the acoustic reflection coefficient in the portion of the acoustic spectrum of said selected components; and generating a cement effectiveness signal which is functionally related to said reflection coefficient signals.
Claim 51
Independent Claim
126 words
A method of logging a cased well borehole to determine the effectiveness of cement disposed in the annulus between the casing and the formations comprising the steps of: transmitting a component of acoustic energy radially outwardly from the borehole into the casing and surrounding formations; receiving a reflected portion of said transmitted energy and generating electrical signals representative thereof; separating the signal representative of the received energy into its acoustic frequency spectrum components; selecting at least three of said frequenCy spectrum components over at least three different, relatively wide, bandwidths and generating signals functionally related to the acoustic reflection coefficient in the portion of the acoustic spectrum of said selected components; and generating a cement effectiveness signal which is functionally related to said reflection coefficient signals.
Claim 52
Dependent Claim
39 words
The method of claim 38 wherein the step of generating a cement effectiveness signal is performed by determining the two reflection coefficient signals having the smallest magnitudes and generating a signal representative of the average of these two signals.
Claim 53
Dependent Claim
41 words
The method of claim 38 wherein the step of generating a cement effectiveness signal is performed by determining the two reflection coefficient signals having most nearly the same magnitude and generating a signal representative of the average of these two signals.
Claim 54
Dependent Claim
38 words
The method of claim 38 wherein the step of generating a cement effectiveness signal includes selecting the two reflection coefficient signals having the smallest magnitudes and generating from such selected signals said signal representative of the cement effectiveness.
Claim 55
Dependent Claim
40 words
The method of claim 38 wherein the step of generating a cement effectiveness signal includes selecting the two reflection coefficient signals having most nearly the same magnitude and generating from such selected signals said signal representative of the cement effectiveness.
Claim 56
Independent Claim
112 words
A method of process1ng data representative of radially reflected acoustic energy received in a cased well borehole to determine the effectiveness of cement disposed in the annulus between a casing and surrounding formations comprising the steps of: separating said data representative of the received energy into its acoustic frequency spectrum components; selecting a plurality of said frequency spectrum components over a plurality of different, relatively wide, bandwidths; generating from said selected plurality frequency spectrum components data functionally related to the acoustic reflection coefficient in the portion of the acoustic spectrum of each of said selected spectrum components; and generating a cement effectiveness output which is functionally related to said reflection coefficient data.
Claim 57
Independent Claim
112 words
A method of process1ng data representative of radially reflected acoustic energy received in a cased well borehole to determine the effectiveness of cement disposed in the annulus between a casing and surrounding formations comprising the steps of: separating said data representative of the received energy into its acoustic frequency spectrum components; selecting a plurality of said frequency spectrum components over a plurality of different, relatively wide, bandwidths; generating from said selected plurality frequency spectrum components data functionally related to the acoustic reflection coefficient in the portion of the acoustic spectrum of each of said selected spectrum components; and generating a cement effectiveness output which is functionally related to said reflection coefficient data.
Claim 58
Dependent Claim
45 words
The method of claim 43 wherein the step of generating a cement effectiveness output includes selecting the reflection coefficient data from at least two of said frequency spectra having the smallest magnitudes and generating from such selected data said output representative of the cement effectiveness.
Claim 59
Dependent Claim
46 words
The method of claim 43 wherein the step of generating a cement effectiveness output includes selecting the two reflection coefficient data from at least two of said frequency spectra having the smallest magnitudes and generating from such selected data said output representative of the cement effectiveness.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-23 | 1977-01-22 | 1977-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-23 | 1981-01-22 | 1981-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-23 | 1985-01-22 | 1985-07-24 | $7700.00 | Window Closed / Lapsed |