Patent US3558888A successfully refreshed from Google Patents.
US3558888A
Expired / Lapsed
US
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Neutron well logging method and apparatus
Assignee: Western Atlas International Inc
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Filing: 1967-05-12
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Granted: 1971-01-26
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Expires: 1987-05-12
Abstract
Abstract Radioactivity method and apparatus for measuring the oil in invaded zone of an earth formation, wherein the thermal neutron capture cross section of the mud filtrate is altered to correspond to that of the formation water, and wherein the amount of oil remaining the invaded zone is measured as a function of the macroscopic thermal neutron capture cross section of the formation.
Inventors
- 👤 Arthur H Youmans
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:10
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04; G01V5/08; G01V5/10; G01V5/101; G01V5/102; G01V5/107; G01V5/108
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
191 words
A method of determining the amount of oil in a predetermined volumetric unit of a subsurface earth formation containing a liquid and traversed by a borehole, said method comprising: deriving the porosity of said earth formation, deriving the thermal neutron capture cross sections of oil, of the matrix of said formation and of the water in said formation, deriving the macroscopic thermal neutron capture cross section of said formation, and deriving an indication of the volume of oil in said volumetric unit of said formation according to the relationship: wherein Sigma formation is the macroscopic thermal neutron capture cross section of said formation, Sigma matrix is the thermal neutron capture cross section of said matrix, Sigma water is the thermal neutron capture cross section of said water, Sigma oil is the thermal neutron capture cross section of oil, phi is the porosity of said formation, Sw is the fractional portion of the total liquid in said unit of said formation which is water, wherein So is the fractional portion of the total liquid in said unit of said formation which is oil, and wherein So plus Sw is equal to unity.
Claim 2
Independent Claim
191 words
A method of determining the amount of oil in a predetermined volumetric unit of a subsurface earth formation containing a liquid and traversed by a borehole, said method comprising: deriving the porosity of said earth formation, deriving the thermal neutron capture cross sections of oil, of the matrix of said formation and of the water in said formation, deriving the macroscopic thermal neutron capture cross section of said formation, and deriving an indication of the volume of oil in said volumetric unit of said formation according to the relationship: wherein Sigma formation is the macroscopic thermal neutron capture cross section of said formation, Sigma matrix is the thermal neutron capture cross section of said matrix, Sigma water is the thermal neutron capture cross section of said water, Sigma oil is the thermal neutron capture cross section of oil, phi is the porosity of said formation, Sw is the fractional portion of the total liquid in said unit of said formation which is water, wherein So is the fractional portion of the total liquid in said unit of said formation which is oil, and wherein So plus Sw is equal to unity.
Claim 3
Dependent Claim
73 words
The method as described in claim 1, wherein the macroscopic thermal neutron capture cross section of said formation is derived by: irradiating said formation with a burst of fast neutrons, detecting during at least two discrete time intervals radiations occasioned in said formation by said fast neutrons, and deriving a function of the ratio of said radiations detected during one of said intervals to the radiations detected during the other of said intervals.
Claim 4
Dependent Claim
14 words
The method as described in claim 2, wherein said detected radiations are thermal neutrons.
Claim 5
Dependent Claim
14 words
The method as described in claim 2, wherein said detected radiations are gamma rays.
Claim 6
Independent Claim
91 words
A method of investigating the character of a subsurface earth formation traversed by a borehole, said method comprising: injecting into said earth formation a fluid having a preselected thermal neutron capture cross section, thereafter irradiating said fluid and said formation with a discrete burst of fast neutrons, detecting during at least two discrete successive time intervals radiations occasioned in said formation by said fast neutrons, and deriving a function of the ratio of said radiations detected during one of said intervals to the radiations detected during the other of said intervals.
Claim 7
Independent Claim
91 words
A method of investigating the character of a subsurface earth formation traversed by a borehole, said method comprising: injecting into said earth formation a fluid having a preselected thermal neutron capture cross section, thereafter irradiating said fluid and said formation with a discrete burst of fast neutrons, detecting during at least two discrete successive time intervals radiations occasioned in said formation by said fast neutrons, and deriving a function of the ratio of said radiations detected during one of said intervals to the radiations detected during the other of said intervals.
Claim 8
Dependent Claim
33 words
The method described in claim 5, wherein said injected fluid is injected so as to partially displace any natural fluids in said formation from the region of said formation immediately proximate said borehole.
Claim 9
Dependent Claim
33 words
The method described in claim 6, wherein said borehole contains a metal pipe, and wherein said steps of irradiating said formation and detecting said radiations are performed at a location within said pipe.
Claim 10
Dependent Claim
24 words
The method described in claim 6, wherein said injected fluid contains a material selected from the group consisting of boric acid and lithium citrate.
Claim 11
Dependent Claim
24 words
The method described in claim 8, wherein said selected material is enriched by an element selected from the group consisting of boron-10 and lithium-6.
Claim 12
Independent Claim
121 words
A method of making a quantitative determination of the oil in a subsurface earth formation traversed by a borehole and Containing oil and formation water, said method comprising the steps of: injecting a fluid into said formation to displace at least a portion of said oil and formation water from a first zone in said formation surrounding said borehole into a second zone surrounding said first zone, thereafter irradiating said formation with a discrete burst of fast neutrons, detecting during at least two successive discrete time intervals radiations occasioned in said formation by said neutrons, and counting the radiations detected during each of said intervals, and deriving the macroscopic thermal neutron capture cross section of said formation in said first zone.
Claim 13
Independent Claim
121 words
A method of making a quantitative determination of the oil in a subsurface earth formation traversed by a borehole and Containing oil and formation water, said method comprising the steps of: injecting a fluid into said formation to displace at least a portion of said oil and formation water from a first zone in said formation surrounding said borehole into a second zone surrounding said first zone, thereafter irradiating said formation with a discrete burst of fast neutrons, detecting during at least two successive discrete time intervals radiations occasioned in said formation by said neutrons, and counting the radiations detected during each of said intervals, and deriving the macroscopic thermal neutron capture cross section of said formation in said first zone.
Claim 14
Dependent Claim
30 words
The method described in claim 10, wherein said injected fluid has a thermal neutron capture cross section substantially equal to the thermal neutron capture cross section of said formation water.
Claim 15
Dependent Claim
28 words
The method as described in claim 11, wherein said injected fluid contains a preselected amount of material selected from the group consisting of boric acid and lithium citrate.
Claim 16
Dependent Claim
24 words
The method as described in claim 12, wherein said material is enriched by an element selected from the group consisting of boron-10 and lithium-6.
Claim 17
Dependent Claim
18 words
The method as described in claim 13, wherein said injected fluid is substantially composed of drilling mud filtrate.
Claim 18
Independent Claim
133 words
A method of making a quantitative determination of the movable oil in a subsurface earth formation, said method comprising the steps of: injecting into a portion of said formation so as to at least partially displace the natural fluids therein a preselected fluid having a thermal neutron capture cross section substantially the same as that of any formation water in said formation, making a first measurement of the amount of oil remaining in said portion of said formation invaded by said preselected fluid, permitting the natural fluids in said formation to return to said portion invaded by said preselected fluid, making a second measurement of the amount of oil in said portion of said formation after said natural fluids are permitted to return to said portion, and comparing said first and second measurements.
Claim 19
Independent Claim
133 words
A method of making a quantitative determination of the movable oil in a subsurface earth formation, said method comprising the steps of: injecting into a portion of said formation so as to at least partially displace the natural fluids therein a preselected fluid having a thermal neutron capture cross section substantially the same as that of any formation water in said formation, making a first measurement of the amount of oil remaining in said portion of said formation invaded by said preselected fluid, permitting the natural fluids in said formation to return to said portion invaded by said preselected fluid, making a second measurement of the amount of oil in said portion of said formation after said natural fluids are permitted to return to said portion, and comparing said first and second measurements.
Claim 20
Dependent Claim
200 words
The method as described in claim 15, wherein the step of making said first measurement includes the steps of: deriving the porosity of said earth formation, deriving the thermal neutron capture cross sections of oil, of the matrix of said formation, and of the water in said formation, deriving the macroscopic thermal neutron capture cross section of said section of said formation, and deriving an indication of the volume of oil in a preselected volumetric unit of said section of said formation according to the relationship: wherein Sigma formation formation is the macroscopic thermal neutron capture cross section of said formation, Sigma matrix is the thermal neutron capture cross section of said matrix, Sigma water water is the thermal neutron capture cross section of said formation water and said injected fluid, Sigma oil oil is the thermal neutron capture cross section of oil, phi is the porosity of said formation, Sw is the fractional portion of the total fluid in said section of said formation which is formation water and injected fluid, wherein So is the fractional portion of the total fluid in said section of said formation which is oil, and wherein So plus Sw is equal to unity.
Claim 21
Dependent Claim
79 words
The method described in claim 16, wherein the step of deriving the macroscopic thermal neutron capture cross section of said section of said formation includes the steps of: irradiating said formation with a burst of fast neutrons, detecting during at least two discrete time intervals occasioned in said formation by said fast neutrons, and deriving a function of the ratio of said radiations detected during one of said intervals to the radiations detected during the other of said inteRvals.
Claim 22
Dependent Claim
24 words
The method described in claim 17, wherein said injected fluid contains a material selected from the group consisting of boric acid and lithium citrate.
Claim 23
Dependent Claim
24 words
The method described in claim 18, wherein said selected material is enriched with an element selected from the group consisting of boron-10 and lithium-6.
Claim 24
Dependent Claim
13 words
The method described in claim 19, wherein said detected radiations are thermal neutrons.
Claim 25
Dependent Claim
13 words
The method described in claim 19, wherein said detected radiations are gamma rays.
Claim 26
Independent Claim
256 words
A method of making a quantitative determination of the movable oil in a subsurface earth formation, said method comprising the steps of: drilling a borehole into said formation with a drill bit suspended from a string of drill pipe while injecting into the annulus of said borehole and into a portion of said formation drilling mud filtrate having a thermal neutron capture cross section substantially the same as that of any formation water in said formation, thereafter disposing a pulsable source of fast neutrons in said drill pipe adjacent said formation and irradiating said formation with a first pulse of fast neutrons, detecting during at least two discrete time intervals radiations occasioned in said formations by said first pulse of fast neutrons, deriving a function of the ratio of said radiations occasioned by said first pulse of fast neutrons and which are detected during one of said intervals to the radiations detected during the other of said intervals, thereafter removing said drill pipe and inserting a well casing in said borehole, thereafter disposing a pulsable source of fast neutrons in said casing adjacent said formation and irradiating said formation with a second pulse of fast neutrons, detecting during at least two discrete time intervals radiations occasioned in said formations by said second pulse of fast neutrons, deriving a function of the ratio of said radiations occasioned by said second pulse of fast neutrons and which are detected during one of said intervals to the radiations detected during the other of said intervals, and comparing said derivations.
Claim 27
Independent Claim
256 words
A method of making a quantitative determination of the movable oil in a subsurface earth formation, said method comprising the steps of: drilling a borehole into said formation with a drill bit suspended from a string of drill pipe while injecting into the annulus of said borehole and into a portion of said formation drilling mud filtrate having a thermal neutron capture cross section substantially the same as that of any formation water in said formation, thereafter disposing a pulsable source of fast neutrons in said drill pipe adjacent said formation and irradiating said formation with a first pulse of fast neutrons, detecting during at least two discrete time intervals radiations occasioned in said formations by said first pulse of fast neutrons, deriving a function of the ratio of said radiations occasioned by said first pulse of fast neutrons and which are detected during one of said intervals to the radiations detected during the other of said intervals, thereafter removing said drill pipe and inserting a well casing in said borehole, thereafter disposing a pulsable source of fast neutrons in said casing adjacent said formation and irradiating said formation with a second pulse of fast neutrons, detecting during at least two discrete time intervals radiations occasioned in said formations by said second pulse of fast neutrons, deriving a function of the ratio of said radiations occasioned by said second pulse of fast neutrons and which are detected during one of said intervals to the radiations detected during the other of said intervals, and comparing said derivations.
Claim 28
Dependent Claim
78 words
The method described in claim 22, wherein said drilling mud filtrate injected into the annulus of said borehole containing said drill pipe at least partially displaces the natural fluids in said portion of said formation, and wherein said displaced fluids are permitted to at least partially displace said mud filtrate from said portion of said formation after said well casing is inserted into said borehole and before said formation is irradiated with said second pulse of fast neutrons.
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) | 1974-01-25 | 1974-07-27 | 1975-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-25 | 1978-07-27 | 1979-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-25 | 1982-07-27 | 1983-01-26 | $7700.00 | Window Closed / Lapsed |