US3864569A
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Well logging processing method and apparatus
Assignee: Schlumberger Technology Corp
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Filing: 1973-04-13
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Granted: 1975-02-04
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Expires: 1993-04-13
Abstract
Abstract A specific embodiment of the invention identifies the chemical composition of an earth formation and compensates for mudcake during well logging. The formation is irradiated with photons that have energies less than about 1 mev. A low energy gamma radiation detector is positioned close to the gamma radiation source primarily to measure borehole parameters, while a second low energy gamma radiation detector, spaced more distantly from the gamma ray source, measures borehole characteristics and the mineral composition of the formation. The signals from the detectors are normalized and combined to produce an output that identifies formation lithology and effective mudcake thickness.
Inventors
- 👤 Jay Tittman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:40
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04; G01V5/08; G01V5/12; G01V5/125
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
150 words
A computer for identifying earth formation characteristics, comprising means for producing a first and a second signal corresponding to an energy spectrum of a plurality of photon intensities, said first signal corresponding to photon intensities in an energy spectrum below a predetermined energy level and the second signal corresponding to photon intensities in an energy spectrum greater than a predetermined energy level, means for normalizing said first and second signals, means for producing third and fourth signals that correspond to an energy spectrum of a plurality of photon intensities, said third signal corresponding to the photon intensities in an energy spectrum below a predetermined energy level and said fourth signal corresponding to photon intensities in an energy spectrum greater than a predetermined energy level, means for normalizing said third and fourth signals and means for combining said normalized signals to produce at least one signal that identifies earth formation characteristics.
Claim 2
Dependent Claim
150 words
A computer for identifying earth formation characteristics, comprising means for producing a first and a second signal corresponding to an energy spectrum of a plurality of photon intensities, said first signal corresponding to photon intensities in an energy spectrum below a predetermined energy level and the second signal corresponding to photon intensities in an energy spectrum greater than a predetermined energy level, means for normalizing said first and second signals, means for producing third and fourth signals that correspond to an energy spectrum of a plurality of photon intensities, said third signal corresponding to the photon intensities in an energy spectrum below a predetermined energy level and said fourth signal corresponding to photon intensities in an energy spectrum greater than a predetermined energy level, means for normalizing said third and fourth signals and means for combining said normalized signals to produce at least one signal that identifies earth formation characteristics.
Claim 3
Dependent Claim
56 words
A computer, according to claim 1, wherein said first and third signals represent soft gamma radiation and said second and fourth signals represent hard gamma radiation and wherein said first and second signals and third and fourth signals are normalized by taking the ratio of the soft gamma ray signal to the hard gamma ray signal.
Claim 4
Independent Claim
138 words
A method of processing well logging signals comprising producing first and second signals corresponding to an energy spectrum of a plurality of photon intensities, said first signal corresponding to photon intensities in an energy spectrum below a predetermined energy level and the second signal corresponding to photon intensities in an energy spectrum greater than a predetermined energy level, normalizing said first and second signals, producing third And fourth signals that correspond to an energy spectrum of a plurality of photon intensities, said third signal corresponding to photon intensities in an energy spectrum less than a predetermined energy level and the fourth signal corresponding to photon intensities in an energy spectrum greater than a predetermined energy level, normalizing said third and fourth signals and combining said normalized signals to produce at least one signal that identifies earth formation characteristics.
Claim 5
Independent Claim
138 words
A method of processing well logging signals comprising producing first and second signals corresponding to an energy spectrum of a plurality of photon intensities, said first signal corresponding to photon intensities in an energy spectrum below a predetermined energy level and the second signal corresponding to photon intensities in an energy spectrum greater than a predetermined energy level, normalizing said first and second signals, producing third And fourth signals that correspond to an energy spectrum of a plurality of photon intensities, said third signal corresponding to photon intensities in an energy spectrum less than a predetermined energy level and the fourth signal corresponding to photon intensities in an energy spectrum greater than a predetermined energy level, normalizing said third and fourth signals and combining said normalized signals to produce at least one signal that identifies earth formation characteristics.
Claim 6
Dependent Claim
45 words
The method of claim 3 wherein said first and second signals are normalized by taking the ratio of the first signal to the second signal and the third and fourth signals are normalized by taking the ratio of the third signal to the fourth signal.
Claim 7
Dependent Claim
27 words
The method of claim 4 wherein said first and third signals represent soft gamma radiation signals and said second and fourth signals represent hard gamma radiation signals.
Claim 8
Dependent Claim
137 words
Apparatus for identifying earth formation characteristics from at least one signal produced in response to radiation emitted into an earth formation from a source of gamma radiation, comprising: a. means for separating said at least one signal into second and third signals, said second signal corresponding to photon intensities in an energy spectrum that is an energy range below a predetermined energy level, said third signal corresponding to photon intensities in an energy spectrum that is in an energy range beginning at and extending above said predetermined energy level, said predetermined energy level being substantially less than the energy level of the radiation source; b. means for combining said second and third signals to produce a normalized signal; and c. means responsive to said normalized signal for producing an output signal indicative of an earth formation characteristic.
Claim 9
Dependent Claim
137 words
Apparatus for identifying earth formation characteristics from at least one signal produced in response to radiation emitted into an earth formation from a source of gamma radiation, comprising: a. means for separating said at least one signal into second and third signals, said second signal corresponding to photon intensities in an energy spectrum that is an energy range below a predetermined energy level, said third signal corresponding to photon intensities in an energy spectrum that is in an energy range beginning at and extending above said predetermined energy level, said predetermined energy level being substantially less than the energy level of the radiation source; b. means for combining said second and third signals to produce a normalized signal; and c. means responsive to said normalized signal for producing an output signal indicative of an earth formation characteristic.
Claim 10
Dependent Claim
38 words
The apparatus of claim 6 wherein said second and third signals are respectively soft and hard gamma radiation signals and said normalized signal is a ratio of the soft gamma radiation signal to the hard gamma radiation signal.
Claim 11
Dependent Claim
22 words
The apparatus of claim 7 wherein the source of radiation is cesium 137 and the predetermined energy level is about 120 KEV.
Claim 12
Independent Claim
134 words
A method for identifying earth formation characteristics from at least one signal produced in response to radiation emitted into an earth formation from a source of gamma radiation, comprising: a. separating said at least one signal into second and third signals, said second signal corresponding to photon intensities in an energy spectrum that is in an energy range below a predetermined energy level, said third signal corresponding to photon intensities in an energy spectrum that is in an energy range beginning at and extending above said predetermined energy level, said predetermined energy level being substantially less than the energy level of the radiation source; b. combining said second and third signals to produce a nomalized signal; and c. producing in response to said normalized signal an output signal indicative of an earth formation characteristic.
Claim 13
Independent Claim
134 words
A method for identifying earth formation characteristics from at least one signal produced in response to radiation emitted into an earth formation from a source of gamma radiation, comprising: a. separating said at least one signal into second and third signals, said second signal corresponding to photon intensities in an energy spectrum that is in an energy range below a predetermined energy level, said third signal corresponding to photon intensities in an energy spectrum that is in an energy range beginning at and extending above said predetermined energy level, said predetermined energy level being substantially less than the energy level of the radiation source; b. combining said second and third signals to produce a nomalized signal; and c. producing in response to said normalized signal an output signal indicative of an earth formation characteristic.
Claim 14
Independent Claim
126 words
A system for processing well logging measurements, comprising means for producing a first signal that corresponds to an energy spectrum of photon intensities derived from a first gamma radiation detector, means for producing a second signal that corresponds to an energy spectrum of photon intensities derived from a second gamma radiation detector, means for producing a third signal that corresponds to an energy spectrum of photon intensities derived from said second detector and which energy spectrum is different from the other second detector derived energy spectrum, means for combining representation of said second and third signals to produce at least one output signal, and means for utilizing representations of said at least one output signal and said first signal to determine at least one subsurface parameter.
Claim 15
Independent Claim
126 words
A system for processing well logging measurements, comprising means for producing a first signal that corresponds to an energy spectrum of photon intensities derived from a first gamma radiation detector, means for producing a second signal that corresponds to an energy spectrum of photon intensities derived from a second gamma radiation detector, means for producing a third signal that corresponds to an energy spectrum of photon intensities derived from said second detector and which energy spectrum is different from the other second detector derived energy spectrum, means for combining representation of said second and third signals to produce at least one output signal, and means for utilizing representations of said at least one output signal and said first signal to determine at least one subsurface parameter.
Claim 16
Dependent Claim
38 words
The system of claim 10 wherein said means for utilizing includes means for combining representations of said at least one output signal and said first signal to produce an output representation of said at least one subsurface parameter.
Claim 17
Dependent Claim
39 words
The system of claim 10 wherein said representations of second and third signals are combined in a manner to produce an output representation which is functionally related to the ratio of said second and third signals to one another.
Claim 18
Dependent Claim
24 words
The system of claim 10 wherein said at least one subsurface parameter is representative of the lithology of an earth formation adjacent said detectors.
Claim 19
Dependent Claim
29 words
The apparatus of claim 10 wherein said energy spectra for both detectors is substantially less than the initial energy of emitted radiation which causes said detectors to produce signals.
Claim 20
Independent Claim
169 words
A system for processing well logging measurements comprising means for producing a first signal that corresponds to an energy spectrum of photon intensities derived from a first gamma radiation detector, means for producing a second signal that corresponds to an energy spectrum of photon intensities derived from said first detector and which energy spectrum is different from the other spectrum derived from said first detector, means for combining said first and second signals to produce at least one first output signal, means for producing a third signal that corresponds to an energy spectrum of photon intensities derived from a second gamma radiation detector means for producing a fourth signal that corresponds to an energy spectrum of photon intensities derived from said second detector and which energy spectrum is different from other second detector derived energy spectrum, means for combining representations of third and fourth signals to produce at least one second output signal, and means for utilizing representations of said output signals to determine at least one subsurface paramenter.
Claim 21
Independent Claim
169 words
A system for processing well logging measurements comprising means for producing a first signal that corresponds to an energy spectrum of photon intensities derived from a first gamma radiation detector, means for producing a second signal that corresponds to an energy spectrum of photon intensities derived from said first detector and which energy spectrum is different from the other spectrum derived from said first detector, means for combining said first and second signals to produce at least one first output signal, means for producing a third signal that corresponds to an energy spectrum of photon intensities derived from a second gamma radiation detector means for producing a fourth signal that corresponds to an energy spectrum of photon intensities derived from said second detector and which energy spectrum is different from other second detector derived energy spectrum, means for combining representations of third and fourth signals to produce at least one second output signal, and means for utilizing representations of said output signals to determine at least one subsurface paramenter.
Claim 22
Independent Claim
115 words
A method of processing well logging measurements comprising producing a first signal that corresponds to an energy spectrum of photon intensities derived from a first gamma radiation detector, producing a second signal that corresponds to an energy spectrum of photon intensities derived from a second gamma radiation detector, producing a third signal that corresponds to an energy spectrum of photon intensities derived from said second detector and which energy spectrum is different from the other second detector derived energy spectrum, combining representations of second and third signals to produce at least one output signal, and utilizing representations of said at least one output signal and said first signal to determine at least one subsurface parameter.
Claim 23
Independent Claim
115 words
A method of processing well logging measurements comprising producing a first signal that corresponds to an energy spectrum of photon intensities derived from a first gamma radiation detector, producing a second signal that corresponds to an energy spectrum of photon intensities derived from a second gamma radiation detector, producing a third signal that corresponds to an energy spectrum of photon intensities derived from said second detector and which energy spectrum is different from the other second detector derived energy spectrum, combining representations of second and third signals to produce at least one output signal, and utilizing representations of said at least one output signal and said first signal to determine at least one subsurface parameter.
Claim 24
Dependent Claim
36 words
The system of claim 16 wherein said step of utilizing includes combining representations of said at least one output signal and said first signal to produce an output representation of said at least one subsurface parameter.
Claim 25
Dependent Claim
39 words
The system of claim 16 wherein said representations of second and third signals are combined in a manner to produce an output representation which is functionally related to the ratio of said second and third signals to one another.
Claim 26
Dependent Claim
24 words
The method of claim 16 wherein said at least one subsurface parameter is representative of the lithology of an earth formation adjacent said detectors.
Claim 27
Dependent Claim
29 words
The method of claim 16 wherein said energy spectra for both detectors is substantially less than the initial energy of emitted radiation which causes said detectors to produce signals.
Claim 28
Dependent Claim
24 words
The method of claim 18 wherein said at least one subsurface parameter is representative of the lithology of an earth formation adjacent said detector.
Claim 29
Independent Claim
157 words
A method of processing well logging measurements comprising producing a first signal that corresponds to an energy spectrum of photon intensities derived from a first gamma radiation detector, producing a second signal that corresponds to an energy spectrum of photon intensities derived from said first detector and which energy spectrum is different from the other spectrum derived from saiD first detector, combining said first and second signals to produce at least one first output signal, producing a third signal that corresponds to an energy spectrum of photon intensities derived from a second gamma radiation detector, producing a fourth signal that corresponds to an energy spectrum of photon intensities derived from said second detector and which energy spectrum is different from the other second detector derived energy spectrum, combining representations of said third and fourth signals to produce at least one second output signal and utilizing representations of said output signals to determine at least one subsurface parameter.
Claim 30
Independent Claim
157 words
A method of processing well logging measurements comprising producing a first signal that corresponds to an energy spectrum of photon intensities derived from a first gamma radiation detector, producing a second signal that corresponds to an energy spectrum of photon intensities derived from said first detector and which energy spectrum is different from the other spectrum derived from saiD first detector, combining said first and second signals to produce at least one first output signal, producing a third signal that corresponds to an energy spectrum of photon intensities derived from a second gamma radiation detector, producing a fourth signal that corresponds to an energy spectrum of photon intensities derived from said second detector and which energy spectrum is different from the other second detector derived energy spectrum, combining representations of said third and fourth signals to produce at least one second output signal and utilizing representations of said output signals to determine at least one subsurface parameter.
Claim 31
Dependent Claim
36 words
The method of claim 22 wherein said step of utilizing includes combining representations of said at least one output signal and said first signal to produce an output representation of said at least one subsurface parameter.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-03 | 1978-08-05 | 1979-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-03 | 1982-08-05 | 1983-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-03 | 1986-08-05 | 1987-02-04 | $7700.00 | Window Closed / Lapsed |