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US4385235A
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Method and apparatus for measuring the thermal neutron absorption rate in earth formations
Assignee: Western Atlas International Inc
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Filing: 1980-11-17
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Granted: 1983-05-24
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Expires: 2000-11-17
Abstract
Abstract Circuitry is provided for establishing the points in time at which radiation is detected following neutron bursts in pulsed neutron logging. Means are provided to generate a signal indicative of the average time measurement of a predetermined number of detected pulses within a detection gate interval. A first counter circuit establishes a time position for each detected pulse within the detection interval. The time measurement signal is loaded into a down counter which transfers the individual time to a third accumulator circuit where the times signals for a predetermined number of detected pulses are compiled. The total time signal is averaged by dividing the accumulated value by the predetermined number of processed pulses. The resultant value is used to establish the macroscopic thermal neutron capture cross-section of the formation.
Inventors
- 👤 Mark W. Hastings
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:53
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04; G01V5/08; G01V5/10; G01V5/107; G01V5/108
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
135 words
Apparatus for determining the macroscopic thermal neutron capture cross-section of earth substances, comprising: means for irradiating said substances with time-spaced bursts of neutrons; means for detecting radiations occasioned in said irradiated substances by said bursts of neutrons during a preselected time interval following each burst of neutrons; means for generating electrical pulses indicative of said detected radiation; circuit means for determining the time relationship of each of said electrical pulses with respect to the start of said preselected time interval; circuit means for accumulating the time relationships of a predetermined number of said electrical pulses and generating a signal representative of the average time relationship of said predetermined number of electrical pulses; and circuit means for computing the macroscopic thermal neutron capture cross-section from said average time relationship of said predetermined number of electrical pulses.
Claim 2
Dependent Claim
135 words
Apparatus for determining the macroscopic thermal neutron capture cross-section of earth substances, comprising: means for irradiating said substances with time-spaced bursts of neutrons; means for detecting radiations occasioned in said irradiated substances by said bursts of neutrons during a preselected time interval following each burst of neutrons; means for generating electrical pulses indicative of said detected radiation; circuit means for determining the time relationship of each of said electrical pulses with respect to the start of said preselected time interval; circuit means for accumulating the time relationships of a predetermined number of said electrical pulses and generating a signal representative of the average time relationship of said predetermined number of electrical pulses; and circuit means for computing the macroscopic thermal neutron capture cross-section from said average time relationship of said predetermined number of electrical pulses.
Claim 3
Dependent Claim
23 words
The apparatus for determining the macroscopic thermal neutron capture cross-section of claim 1, wherein said preselected time interval is 600 microseconds in duration.
Claim 4
Dependent Claim
26 words
The apparatus for determining the macroscopic thermal neutron capture cross-section of claim 2, wherein said preselected time interval begins 400 microseconds following each burst of neutrons.
Claim 5
Dependent Claim
22 words
The apparatus for determining the macroscopic thermal neutron capture cross-section of claim 3, wherein said bursts of neutrons occurs every 1100 microseconds.
Claim 6
Dependent Claim
70 words
The apparatus for determining the macroscopic thermal neutron capture cross-section of claim 1, wherein said circuit means for determining the time relationship of each of said electrical pulses comprises: first counter means for counting from the start of said time interval until the arrival of each of said electrical pulses; and second counter means for counting from the arrival of each of said electrical pulses to a zero time value.
Claim 7
Dependent Claim
24 words
The apparatus for determining the macroscopic thermal neutron capture cross-section of claim 1, wherein said predetermined number of electrical pulses is equal to thirty-two.
Claim 8
Independent Claim
67 words
A method of well logging, comprising: pulsedly irradiating the formations surrounding a well with repetitive discrete bursts of high energy neutrons; detecting radiation occurring in said well resulting from each bursts of neutrons; generating time-separated electrical pulses indicative of said detected radiation; generating a plurality of electrical signals, each of said signals being representative of the average time of a predetermined number of said time-separated electrical pulses.
Claim 9
Independent Claim
67 words
A method of well logging, comprising: pulsedly irradiating the formations surrounding a well with repetitive discrete bursts of high energy neutrons; detecting radiation occurring in said well resulting from each bursts of neutrons; generating time-separated electrical pulses indicative of said detected radiation; generating a plurality of electrical signals, each of said signals being representative of the average time of a predetermined number of said time-separated electrical pulses.
Claim 10
Dependent Claim
105 words
Apparatus for determining the average time relationship of a predetermined number of radiation pulses within a radiation detection interval, comprising: first counter means for generating first signals functionally related to the arrival of each of said radiation pulses within said detection interval; second counter means for generating second signals functionally related to said first signals, said second signals being generated at an increased repetition rate from said first signals; third counter means for accumulating a predetermined number of said second signals and generating an output signal, said output signal being functionally related to the average time relationship of a predetermined number of said radiation pulses.
Claim 11
Dependent Claim
105 words
Apparatus for determining the average time relationship of a predetermined number of radiation pulses within a radiation detection interval, comprising: first counter means for generating first signals functionally related to the arrival of each of said radiation pulses within said detection interval; second counter means for generating second signals functionally related to said first signals, said second signals being generated at an increased repetition rate from said first signals; third counter means for accumulating a predetermined number of said second signals and generating an output signal, said output signal being functionally related to the average time relationship of a predetermined number of said radiation pulses.
Claim 12
Dependent Claim
24 words
The apparatus of claim 8, further comprising means for converting said average time signal to the macroscopic neutron capture cross-section of an earth substance.
Claim 13
Dependent Claim
24 words
The apparatus of claim 9, further comprising fourth counter means for resetting said third counter after said predetermined number of electrical pulses are detected.
Claim 14
Dependent Claim
16 words
The apparatus of claim 10, wherein said predetermined number of electrical pulses is equal to thirty-two.
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) | 1986-05-23 | 1986-11-22 | 1987-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-23 | 1990-11-22 | 1991-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-23 | 1994-11-22 | 1995-05-24 | $7700.00 | Window Closed / Lapsed |