US3869608A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nuclear well logging
Assignee: SCHERBATSKOY FAMILY TRUST
•
Filing: 1953-07-01
•
Granted: 1975-03-04
•
Expires: 1973-07-01
Abstract
Abstract This invention comprises apparatus for detecting the compositions of materials, and specifically for logging oil well bores. The apparatus comprises a neutron generator; a scintillation crystal responsive to gamma rays, slow neutrons and fast neutrons; and a photocell responsive to the scintillations of the crystal. Means is provided for amplifying, detecting, and recording the action of the photocell to provide recorded traces of the gamma rays, and slow and fast neutrons. Means is provided for calibrating the instrument from the ground surface.
Inventors
- 👤 Serge A Scherbatskoy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:34
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04; G01V5/08; G01V5/10; G01V5/104
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
250 words
A radioactivity well logging system for determining the oilwater interface in a fluid bearing formation traversed by a borehole, comprising a subsurface unit, means including a cable for lowering said unit into the borehole, a source of fast neutrons in said unit for bombarding with fast neutrons the formations traversed by the borehole as said unit is moved therewithin, fast neutron detector means in said unit for producing impulses corresponding to fast neutrons received from the formations the magnitude of which is related to the energy of the corresponding fast neutrons, a first pair of electrical selective networks for selecting only those impulses which fall within first and second narrow ranges of impulses height corresponding to predetermined related portions of the neutron cross section characteristic of the element carbon, a second pair of electrical selective networks for selecting only those impulses which fall within third and fourth narrow ranges of impulse heights, corresponding to predetermined related portions of the neutron cross section characteristic of the element oxygen, first ratio meter means for developing a first voltage proportional to the ratio of the outputs of said first pair of said selective electrical networks, second ratio meter means for developing a second voltage proportional to the ratio of the outputs of said second pair of said selective electrical networks, and means including third ratio meter means for producing an indication proportional to the ratio of said first and second voltages, whereby the oil-water interface in a fluid bearing formation may be detected.
Claim 2
Dependent Claim
250 words
A radioactivity well logging system for determining the oilwater interface in a fluid bearing formation traversed by a borehole, comprising a subsurface unit, means including a cable for lowering said unit into the borehole, a source of fast neutrons in said unit for bombarding with fast neutrons the formations traversed by the borehole as said unit is moved therewithin, fast neutron detector means in said unit for producing impulses corresponding to fast neutrons received from the formations the magnitude of which is related to the energy of the corresponding fast neutrons, a first pair of electrical selective networks for selecting only those impulses which fall within first and second narrow ranges of impulses height corresponding to predetermined related portions of the neutron cross section characteristic of the element carbon, a second pair of electrical selective networks for selecting only those impulses which fall within third and fourth narrow ranges of impulse heights, corresponding to predetermined related portions of the neutron cross section characteristic of the element oxygen, first ratio meter means for developing a first voltage proportional to the ratio of the outputs of said first pair of said selective electrical networks, second ratio meter means for developing a second voltage proportional to the ratio of the outputs of said second pair of said selective electrical networks, and means including third ratio meter means for producing an indication proportional to the ratio of said first and second voltages, whereby the oil-water interface in a fluid bearing formation may be detected.
Claim 3
Dependent Claim
117 words
In an apparatus for measuring frequency of arrival of incoming particles having characteristic energy, a detector responsive to said particles for producing a succession of impulses representing the frequency of arrival of said particles, the magnitude of said impulses representing said energy, a source of reference particles of known energy, shielding means normally preventing said reference particles from causing a response in said detector, means for varying said shielding means to permit said reference particles to cause a response in said detector, whereby said detector produces reference impulses in response to said reference particles, the magnitude of said reference impulses indicating the sensitivity of said detector, and means for controlling the magnitude of said first named impulses.
Claim 4
Dependent Claim
117 words
In an apparatus for measuring frequency of arrival of incoming particles having characteristic energy, a detector responsive to said particles for producing a succession of impulses representing the frequency of arrival of said particles, the magnitude of said impulses representing said energy, a source of reference particles of known energy, shielding means normally preventing said reference particles from causing a response in said detector, means for varying said shielding means to permit said reference particles to cause a response in said detector, whereby said detector produces reference impulses in response to said reference particles, the magnitude of said reference impulses indicating the sensitivity of said detector, and means for controlling the magnitude of said first named impulses.
Claim 5
Dependent Claim
131 words
In an apparatus for measuring frequency of arrival of incoming particles having characteristic energy, a gas-filled detector responsive to said particles for producing a succession of impulses representing the frequency of arrival of said particles, the magnitude of said impulses representing said energy, a source of reference particles of known energy positioned inside said detector, shielding means inside said detector normally shielding said source to prevent said detector from responding to said reference particles, means controllable externally of said detector for varying said shielding means to permit said reference particles to cause a response in said detector, whereby said detector produces reference impulses in response to said reference particles, the magnitude of said reference impulses indicating the sensitivity of said detector, and means for controlling the magnitude of said first impulses.
Claim 6
Dependent Claim
131 words
In an apparatus for measuring frequency of arrival of incoming particles having characteristic energy, a gas-filled detector responsive to said particles for producing a succession of impulses representing the frequency of arrival of said particles, the magnitude of said impulses representing said energy, a source of reference particles of known energy positioned inside said detector, shielding means inside said detector normally shielding said source to prevent said detector from responding to said reference particles, means controllable externally of said detector for varying said shielding means to permit said reference particles to cause a response in said detector, whereby said detector produces reference impulses in response to said reference particles, the magnitude of said reference impulses indicating the sensitivity of said detector, and means for controlling the magnitude of said first impulses.
Claim 7
Dependent Claim
147 words
In an apparatus for measuring frequency of arrival of incoming particles having characteristic energy, a detector responsive to said particles for producing a succession of impulses representing the frequency of arrival of said particles, the magnitude of said impulses representing said energy, a source of reference particles of known energy, means including a thin membrane positioned between said source and said detector for reducing the energy of reference particles emitted by said source in the direction of said detector, shielding means normally preventing reference particles traversing said membrane from causing a response in said detector, means for varying said shielding means to permit said detector to respond to reference particles traversing said membrane, whereby said detector prduces reference impulses in response to said reference particles, the magnitude of said reference impulses indicating the sensitivity of said detector, and means for controlling the magnitude of said first impulses.
Claim 8
Dependent Claim
147 words
In an apparatus for measuring frequency of arrival of incoming particles having characteristic energy, a detector responsive to said particles for producing a succession of impulses representing the frequency of arrival of said particles, the magnitude of said impulses representing said energy, a source of reference particles of known energy, means including a thin membrane positioned between said source and said detector for reducing the energy of reference particles emitted by said source in the direction of said detector, shielding means normally preventing reference particles traversing said membrane from causing a response in said detector, means for varying said shielding means to permit said detector to respond to reference particles traversing said membrane, whereby said detector prduces reference impulses in response to said reference particles, the magnitude of said reference impulses indicating the sensitivity of said detector, and means for controlling the magnitude of said first impulses.
Claim 9
Dependent Claim
151 words
In an apparatus for measuring frequency of arrival of incoming particles having characteristic energy, a detector responsive to said particles for producing a succession of impulses representing the frequency of arrival of said particles, the magnitude of said impulses representing said energy, a source of alpha particles of relatively high energy, means including a thin membrane positioned between said source and said detector for reducing the energy of alpha particles emitted by said source in the direction of said detector, shielding means normally preventing those alpha particles which traverse said membrane from causing a response in said detector, means for varying and shielding means to permit said detector to respond to alpha particles which traverse said membrane, whereby said detector produces reference impulses in response to said alpha particles, the magnitude of said reference impulses indicating the sensitivity of said detector, and means for controlling the magnitude of said first impulses.
Claim 10
Dependent Claim
151 words
In an apparatus for measuring frequency of arrival of incoming particles having characteristic energy, a detector responsive to said particles for producing a succession of impulses representing the frequency of arrival of said particles, the magnitude of said impulses representing said energy, a source of alpha particles of relatively high energy, means including a thin membrane positioned between said source and said detector for reducing the energy of alpha particles emitted by said source in the direction of said detector, shielding means normally preventing those alpha particles which traverse said membrane from causing a response in said detector, means for varying and shielding means to permit said detector to respond to alpha particles which traverse said membrane, whereby said detector produces reference impulses in response to said alpha particles, the magnitude of said reference impulses indicating the sensitivity of said detector, and means for controlling the magnitude of said first impulses.
Claim 11
Dependent Claim
166 words
In a radioactivity well logging system, a subsurface unit, means incLuding a cable for lowering said unit into a borehole, a radiation detector in said unit for producing logging impulses corresponding to radiations incoming to said unit, the magnitude of said logging impulses representing the energy of said incoming radiations, a soruce of reference particles of known energy in said unit, shielding means in said unit normally preventing said detector from responding to reference particles from said source, means controllable over said cable for varying said shielding means to permit said reference particles to cause a response in said detector, whereby said detector produces reference impulses in response to said reference particles, the magnitude of said reference impulses indicating the sensitivity of said detector, means for transmitting over said cable to the earth''s surface, means for recording the frequency of occurrence of said logging impulses, and means for determining the magnitude of said reference impulses thereby to provide an indication of the sensitivity of said detector.
Claim 12
Dependent Claim
166 words
In a radioactivity well logging system, a subsurface unit, means incLuding a cable for lowering said unit into a borehole, a radiation detector in said unit for producing logging impulses corresponding to radiations incoming to said unit, the magnitude of said logging impulses representing the energy of said incoming radiations, a soruce of reference particles of known energy in said unit, shielding means in said unit normally preventing said detector from responding to reference particles from said source, means controllable over said cable for varying said shielding means to permit said reference particles to cause a response in said detector, whereby said detector produces reference impulses in response to said reference particles, the magnitude of said reference impulses indicating the sensitivity of said detector, means for transmitting over said cable to the earth''s surface, means for recording the frequency of occurrence of said logging impulses, and means for determining the magnitude of said reference impulses thereby to provide an indication of the sensitivity of said detector.
Claim 13
Dependent Claim
209 words
In a radioactivity well logging system, a subsurface unit, means including a cable for lowering said unit into a borehole, a gas-filled radiation detector in said unit for producing logging impulses corresponding to radiations incoming to said unit, the magnitude of said logging impulses representing the energy of said incoming radiations, a source of alpha particles of relatively high energy in said unit, means including a thin membrane positioned between said source and said detector for reducing the energy of alpha particles emitted by said source in the direction of said detector, shielding means in said unit normally preventing those alpha particles which traverse said membrane from causing a response in said detector, means controllable over said cable for varying said shielding means to permit said detector to respond to alpha particles which traverse said membrane, whereby said detector produces reference impulses in response to said alpha particles, the magnitude of said reference impulses indicating the sensitivity of said detector, means for transmitting said logging impulses and said reference impulses over said cable to the earth''s surface, means for recording the frequency of occurrence of said logging impulses, and means for determining the magnitude of said reference impulses, thereby to provide an indication of the sensitivity of said detector.
Claim 14
Dependent Claim
209 words
In a radioactivity well logging system, a subsurface unit, means including a cable for lowering said unit into a borehole, a gas-filled radiation detector in said unit for producing logging impulses corresponding to radiations incoming to said unit, the magnitude of said logging impulses representing the energy of said incoming radiations, a source of alpha particles of relatively high energy in said unit, means including a thin membrane positioned between said source and said detector for reducing the energy of alpha particles emitted by said source in the direction of said detector, shielding means in said unit normally preventing those alpha particles which traverse said membrane from causing a response in said detector, means controllable over said cable for varying said shielding means to permit said detector to respond to alpha particles which traverse said membrane, whereby said detector produces reference impulses in response to said alpha particles, the magnitude of said reference impulses indicating the sensitivity of said detector, means for transmitting said logging impulses and said reference impulses over said cable to the earth''s surface, means for recording the frequency of occurrence of said logging impulses, and means for determining the magnitude of said reference impulses, thereby to provide an indication of the sensitivity of said detector.
Claim 15
Dependent Claim
230 words
Apparatus for analyzing the properties of an unknown substance, comprising a means for generating a stream of neutrons substantially uncontaminated by gamma rays, said means being adapted and positioned to irradiate with neutrons a specimen of the substance to be analyzed, whereby neutrons and gamma rays are emitted by said substance as a result of interaction with said stream, a radiation detector comprising a scintillating phosphor, said detector also comprising in association with said phosphor a material operative to emit, upon undergoing interactions with neutrons, heavy charged particles having rest masses at least as great as that of a proton, said detector being positioned and disposed to receive and intercept neutrons and gamma rays emitted by said specimen in response to said stream of neutrons and to produce trains of electric impulses respectively representing interactions of gamma rays with said phosphor and interactions of heavy charged particles with said phosphor, the magnitudes of the pulses in said respective trains being substantially different, a magnitude-sensitive electrical selective network fed with said impulses from said detector, said network being operative to select and transmit only impulses of magnitudes within the range of magnitudes characteristic of impulses representing interactions of said phosphor with heavy charged particles, and means fed by the output of said selective network for measuring and indicating the frequency of occurrence of the impulses selectively transmitted by said selective network.
Claim 16
Dependent Claim
230 words
Apparatus for analyzing the properties of an unknown substance, comprising a means for generating a stream of neutrons substantially uncontaminated by gamma rays, said means being adapted and positioned to irradiate with neutrons a specimen of the substance to be analyzed, whereby neutrons and gamma rays are emitted by said substance as a result of interaction with said stream, a radiation detector comprising a scintillating phosphor, said detector also comprising in association with said phosphor a material operative to emit, upon undergoing interactions with neutrons, heavy charged particles having rest masses at least as great as that of a proton, said detector being positioned and disposed to receive and intercept neutrons and gamma rays emitted by said specimen in response to said stream of neutrons and to produce trains of electric impulses respectively representing interactions of gamma rays with said phosphor and interactions of heavy charged particles with said phosphor, the magnitudes of the pulses in said respective trains being substantially different, a magnitude-sensitive electrical selective network fed with said impulses from said detector, said network being operative to select and transmit only impulses of magnitudes within the range of magnitudes characteristic of impulses representing interactions of said phosphor with heavy charged particles, and means fed by the output of said selective network for measuring and indicating the frequency of occurrence of the impulses selectively transmitted by said selective network.
Claim 17
Dependent Claim
149 words
Apparatus for measuring a selected componeNt of a complex radiation comprising a radiation detector having means responsive to said complex radiation for releasing two types of charged particles differing with respect to rest mass, the rest mass of one of such types being at least as great as that of a proton, said detector being adapted to produce electric output impulses representing interactions of said charged particles within said detector, the impulses corresponding to said heavy charged particles being substantially different in magnitude from those corresponding to said other type of charged particles, a magnitude-sensitive selective network fed by the output impulses from said detector and operative to select and transmit only output impulses having magnitudes within the range characteristic of said impulses corresponding to heavy charged particles, and means fed by said selectieve network for measuring and indicating the frequency of occurrence of the impulses selectively transmitted thereby.
Claim 18
Dependent Claim
149 words
Apparatus for measuring a selected componeNt of a complex radiation comprising a radiation detector having means responsive to said complex radiation for releasing two types of charged particles differing with respect to rest mass, the rest mass of one of such types being at least as great as that of a proton, said detector being adapted to produce electric output impulses representing interactions of said charged particles within said detector, the impulses corresponding to said heavy charged particles being substantially different in magnitude from those corresponding to said other type of charged particles, a magnitude-sensitive selective network fed by the output impulses from said detector and operative to select and transmit only output impulses having magnitudes within the range characteristic of said impulses corresponding to heavy charged particles, and means fed by said selectieve network for measuring and indicating the frequency of occurrence of the impulses selectively transmitted thereby.
Claim 19
Dependent Claim
132 words
Apparatus for measuring the thermal-neutron component of a complex radiation field comprising a radiation detector operative to produce electric output impulses responsively to interactions within said detector involving electrons, protons, and alpha particles, the impulses corresponding to each of said classes of particles being substantially different in magnitude from those corresponding to said other classes, said detector comprising a material characterized by emission of alpha particles responsively to interactions of such material with thermal neutrons, a magnitude-sensitive selective network fed by the output impulses from said detector and operative to select and transmit only such output impulses as have magnitudes lying within the range characteristic of impulses corresponding to alpha particles, and means fed by said selective network for measuring and indicating the frequency of occurrence of the impulses selectively transmitted thereby.
Claim 20
Dependent Claim
132 words
Apparatus for measuring the thermal-neutron component of a complex radiation field comprising a radiation detector operative to produce electric output impulses responsively to interactions within said detector involving electrons, protons, and alpha particles, the impulses corresponding to each of said classes of particles being substantially different in magnitude from those corresponding to said other classes, said detector comprising a material characterized by emission of alpha particles responsively to interactions of such material with thermal neutrons, a magnitude-sensitive selective network fed by the output impulses from said detector and operative to select and transmit only such output impulses as have magnitudes lying within the range characteristic of impulses corresponding to alpha particles, and means fed by said selective network for measuring and indicating the frequency of occurrence of the impulses selectively transmitted thereby.
Claim 21
Dependent Claim
107 words
Apparatus for measuring incident radiation, comprising a radiation detector having a solid radiation-reactive element, operative to produce electric output impulses responsively to release therewithin of charged particles, said detector comprising means for interaction with said incident radiation operative to release within said detector charged particles of different rest masses, whereby the electric output impulses of said detector are characterized by different ranges of magnitude corresponding to the respective rest masses of the charged particles released within said detector, and a magnitude-selective network fed by the output impulses of said detector for measuring and indicating the frequency of occurrence of the impulses having magnitudes within a predetermined range.
Claim 22
Dependent Claim
107 words
Apparatus for measuring incident radiation, comprising a radiation detector having a solid radiation-reactive element, operative to produce electric output impulses responsively to release therewithin of charged particles, said detector comprising means for interaction with said incident radiation operative to release within said detector charged particles of different rest masses, whereby the electric output impulses of said detector are characterized by different ranges of magnitude corresponding to the respective rest masses of the charged particles released within said detector, and a magnitude-selective network fed by the output impulses of said detector for measuring and indicating the frequency of occurrence of the impulses having magnitudes within a predetermined range.
Claim 23
Dependent Claim
86 words
Apparatus for analyzing the properties of an unknown substance, comprising a discharge tube having a target and means for bombarding the same with deuterons, said tube being operative to generate a stream of neutrons substantially uncontaminated by gamma rays, a radiation detector comprising means for generating electric output impulses of magnitudes dependent upon the character and energy level of intercepted radiation, and magnitude-responsive impulse-selecting means fed by said detector and operative selectively to transmit only such of said impulses as have magnitudes within a predetermined range.
Claim 24
Dependent Claim
86 words
Apparatus for analyzing the properties of an unknown substance, comprising a discharge tube having a target and means for bombarding the same with deuterons, said tube being operative to generate a stream of neutrons substantially uncontaminated by gamma rays, a radiation detector comprising means for generating electric output impulses of magnitudes dependent upon the character and energy level of intercepted radiation, and magnitude-responsive impulse-selecting means fed by said detector and operative selectively to transmit only such of said impulses as have magnitudes within a predetermined range.
Claim 25
Dependent Claim
140 words
Apparatus for analyzing the properties of an unknown substance, comprising a discharge tube having a target and means for bombarding the same with deuterons, said tube being operative to generate a stream of neutrons substantially uncontaminated by gamma rays, a radiation detector characterized by sensitivity to gamma rays and substantial insensitivity to neutrons, said discharge tube an detector being so disposed and positioned that said stream of neutrons can irradiate a specimen of the unknown substance and said detector can receive and intercept gamma rays emitted by said specimen, said radiation detector comprising means for generating electric output impulses of varyiNg magnitudes representing the various energy levels of detected gamma rays, and magnitude-responsive impulse-selecting means fed by said detector and operative selectively to transmit only such of said output impulses from said detector as have magnitudes within a predetermined range.
Claim 26
Dependent Claim
140 words
Apparatus for analyzing the properties of an unknown substance, comprising a discharge tube having a target and means for bombarding the same with deuterons, said tube being operative to generate a stream of neutrons substantially uncontaminated by gamma rays, a radiation detector characterized by sensitivity to gamma rays and substantial insensitivity to neutrons, said discharge tube an detector being so disposed and positioned that said stream of neutrons can irradiate a specimen of the unknown substance and said detector can receive and intercept gamma rays emitted by said specimen, said radiation detector comprising means for generating electric output impulses of varyiNg magnitudes representing the various energy levels of detected gamma rays, and magnitude-responsive impulse-selecting means fed by said detector and operative selectively to transmit only such of said output impulses from said detector as have magnitudes within a predetermined range.
Claim 27
Dependent Claim
120 words
Apparatus for analyzing the properties of an unknown substance, comprising a discharge tube having a target and means for bombarding the same with deuterons, said tube being operative to generate a stream of neutrons substantially uncontaminated by gamma rays, a radiation detector responsive both to gamma rays and neutrons and characterized by emission of electric output impulses produced responsively to intercepted radiation, the range of magnitudes of impulses produced by detected neutrons being substantially different from the range of magnitudes of impulses produced by detected gamma rays, and magnitude-responsive impulse-selecting means fed by said detector and operative separately to select and measure the frequency of occurrence of impulses having magnitudes within predetermined limits embraced wholly within one of said ranges.
Claim 28
Dependent Claim
120 words
Apparatus for analyzing the properties of an unknown substance, comprising a discharge tube having a target and means for bombarding the same with deuterons, said tube being operative to generate a stream of neutrons substantially uncontaminated by gamma rays, a radiation detector responsive both to gamma rays and neutrons and characterized by emission of electric output impulses produced responsively to intercepted radiation, the range of magnitudes of impulses produced by detected neutrons being substantially different from the range of magnitudes of impulses produced by detected gamma rays, and magnitude-responsive impulse-selecting means fed by said detector and operative separately to select and measure the frequency of occurrence of impulses having magnitudes within predetermined limits embraced wholly within one of said ranges.
Claim 29
Dependent Claim
38 words
The apparatus defined in claim 14 wherein said impulse-selecting means is provided also with means for selecting and measuring the frequency of occurrence of impulses having magnitudes within another set of limits within the other of said ranges.
Claim 30
Dependent Claim
80 words
Apparatus for determining radiation intensity comprising a crystal for emitting light flashes proportional to the frequency and energy of the radiation impinged thereupon, a photo cell responsive to said light flashes for emitting electrical pulses proportional thereto, means for amplifying said pulses, a gate circuit including biasing means for passing pulses above a given energy level and for blocking pulses below said level, and a rate meter variably responsive to the frequency of the pulses transmitted by the gate circuit.
Claim 31
Dependent Claim
80 words
Apparatus for determining radiation intensity comprising a crystal for emitting light flashes proportional to the frequency and energy of the radiation impinged thereupon, a photo cell responsive to said light flashes for emitting electrical pulses proportional thereto, means for amplifying said pulses, a gate circuit including biasing means for passing pulses above a given energy level and for blocking pulses below said level, and a rate meter variably responsive to the frequency of the pulses transmitted by the gate circuit.
Claim 32
Dependent Claim
38 words
Apparatus for determining radiation intensity as defined in claim 16 wherein a plurality of gate circuits is provided simultaneously operable and responsive respectively to pulses of different energy levels whereby to measure radiation of selectively different intensity levels.
Claim 33
Dependent Claim
23 words
Apparatus for determining radiation intensity as defined in claim 17 wherein a plurality of rate meters is provided, one for each gate circuit.
Claim 34
Dependent Claim
29 words
Apparatus for determining radiation intensity as defined in claim 16 wherein means is provided responsive to the position of the crystal for producing a record from the rate meter.
Claim 35
Dependent Claim
32 words
Apparatus for determining radiation intensity as defined in claim 18 wherein means is provided responsive to the position of the crystal for producing a plurality of records simultaneously from said rate meters.
Claim 36
Dependent Claim
28 words
Apparatus for determining radiation intensity as defined in claim 16 wherein means is provided for checking the action of the crystal and photo cell against a known standard.
Claim 37
Dependent Claim
24 words
Apparatus for determining radiation intensity as defined in claim 16 wherein temperature adjustment means is provided for controlling the action of the gate circuit.
Claim 38
Dependent Claim
132 words
Well logging apparatus for determining radiation intensity comprising a casing adapted to be lowered into a well bore hole, cable mechanism for controlling the position of the casing, a neutron source carried by the casing, a crystal carried by the casing for emitting light flashes proportional to the frequency and energy of radiation impinged thereupon, a photo cell responsive to said light flashes for emitting electrical pulses proportional thereto, means for amplifying said pulses, a gate circuit including biasing means for passing pulses above a given energy level and for blocking pulses below said level, a rate meter variably responsive to the frequency of the pulses transmitted by the gate circuit, and a recorder controlled by the rate meter and responsive to the position of the casing within the well bore hole.
Claim 39
Dependent Claim
132 words
Well logging apparatus for determining radiation intensity comprising a casing adapted to be lowered into a well bore hole, cable mechanism for controlling the position of the casing, a neutron source carried by the casing, a crystal carried by the casing for emitting light flashes proportional to the frequency and energy of radiation impinged thereupon, a photo cell responsive to said light flashes for emitting electrical pulses proportional thereto, means for amplifying said pulses, a gate circuit including biasing means for passing pulses above a given energy level and for blocking pulses below said level, a rate meter variably responsive to the frequency of the pulses transmitted by the gate circuit, and a recorder controlled by the rate meter and responsive to the position of the casing within the well bore hole.
References Cited (Backward Citations)
US2712081A
Cited
US2275748A
Cited
US2508772A
Cited
US2469460A
Cited
US2469463A
Cited
US2493346A
Cited
US2550107A
Cited
US2686266A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-03 | 1978-09-02 | 1979-03-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-03 | 1982-09-02 | 1983-03-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-03 | 1986-09-02 | 1987-03-04 | $7700.00 | Window Closed / Lapsed |