US4717825A
Expired / Lapsed
US
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Method and apparatus for anomalous radioactive deposition compensation in spectral gamma ray well logging
Assignee: Halliburton Co
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Filing: 1986-07-23
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Granted: 1988-01-05
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Expires: 2006-07-23
Abstract
Abstract A method and apparatus (108) are disclosed for spectral gamma ray logging of a well borehole (106) to determine elemental concentrations of radioactive materials in subsurface earth formations (100) and in the borehole region. Anomalous radioactive deposition in the borehole region is identified and the effect thereof compensated for in the elemental concentration determinations.
Inventors
- 👤 Harry D. Smith, Jr.
- 👤 Larry L. Gadeken
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:59
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04; G01V5/06; G01T; G01T1/00; G01T1/36; G01T1/40
Claims Analysis
Total Claims: 62
Claim 1
Independent Claim
151 words
A method for compensating for anomalous radioactive deposition in the region of a borehole in determining subsurface earth formation natural radioactivity elemental concentrations, comprising: measuring a first reference spectrum of a first radioactive material simulating deposition of said first material in the borehole region; measuring second and third reference spectra simulating deposition of second and third radioactive materials in the said formation, respectively; deriving a set of elemental determination sensitivity matrix elements based on each of said first, second, and third reference spectra; measuring from within said borehole a downhole natural gamma ray energy spectrum of gamma rays originating in and traversing said borehole and formation; determining a condition of anomalous deposition of said first material in said borehole region; and calculating compensated elemental concentrations of said first, second, and third materials from said downhole gamma ray spectrum,a nd said sensitivity matrix element sets for said first, second, and third materials.
Claim 2
Independent Claim
151 words
A method for compensating for anomalous radioactive deposition in the region of a borehole in determining subsurface earth formation natural radioactivity elemental concentrations, comprising: measuring a first reference spectrum of a first radioactive material simulating deposition of said first material in the borehole region; measuring second and third reference spectra simulating deposition of second and third radioactive materials in the said formation, respectively; deriving a set of elemental determination sensitivity matrix elements based on each of said first, second, and third reference spectra; measuring from within said borehole a downhole natural gamma ray energy spectrum of gamma rays originating in and traversing said borehole and formation; determining a condition of anomalous deposition of said first material in said borehole region; and calculating compensated elemental concentrations of said first, second, and third materials from said downhole gamma ray spectrum,a nd said sensitivity matrix element sets for said first, second, and third materials.
Claim 3
Dependent Claim
18 words
The method of claim 1 wherein said first material is a radioisotope of uranium and its daughter products.
Claim 4
Dependent Claim
21 words
The method of claim 2 wherein said second and third materials are radioisotopes of potassium, and thorium and its daughter products.
Claim 5
Dependent Claim
36 words
The method of claim 1 wherein the borehole region in which the measurement is made contains a casing and first material is deposited on the inner casing surface, the outer casing surface, or some combination thereof.
Claim 6
Dependent Claim
28 words
The method of claim 1 wherein said borehole contains a casing surrounded by an annulus of cement and said first radioactive material is deposited within the borehole region.
Claim 7
Dependent Claim
15 words
The method of claim 5 where said first material is uranium or its daughter products.
Claim 8
Dependent Claim
19 words
The method of claim 6 wherein said second and third materials are potassium, and thorium or its daughter products.
Claim 9
Dependent Claim
44 words
The method of claim 1 wherein said determining of elemental concentrations is from said formation spectrum and said sensitivity matrix element sets for said first, said second, and said third spectra, and wherein said second and third matrix elements are corrected for borehole effects.
Claim 10
Dependent Claim
11 words
The method of claim 1 wherein said first material is potassium.
Claim 11
Dependent Claim
21 words
The method of claim 9 wherein said second and third materials are radioisotopes of uranium and thorium and their daughter products.
Claim 12
Dependent Claim
27 words
The method of claim 1 wherein said determining of anomalous deposition step is based on a comparison of a current and hisorical total natural gamma ray logs.
Claim 13
Dependent Claim
38 words
The method of claim 1 wherein said determining step utilizes the magnitude of the residual fitting error between the downhole spectrum and concentrations based on matrix elements derived for all three elements being uniformly distributed in the formation.
Claim 14
Dependent Claim
16 words
The method of claim 1 wherein said determining step uses a priori knowledge of anomalous deposition.
Claim 15
Dependent Claim
19 words
The method of claim 1 wherein said measurements are made and recorded continuously as a function of borehole depth.
Claim 16
Dependent Claim
25 words
The method of claim 1 wherein said anomalous deposition in said determination step utilizes a measurement of relative photoelectric attenuation of said observed downhole spectrum.
Claim 17
Dependent Claim
22 words
The method of claim 15 wherein variations in the photoelectrically sensitive casing ratio measurement R c are used to determine anomalous deposition.
Claim 18
Dependent Claim
18 words
The method of claim 16 wherein said first material is a radioisotope of uranium and its daughter products.
Claim 19
Dependent Claim
21 words
The method of claim 17 wherein said second and third materials are radioisotopes of potassium, and thorium and its daughter products.
Claim 20
Dependent Claim
36 words
The method of claim 16 wherein the borehole region in which the measurement is made contains a casing and first material is deposited on the inner casing surface, the outer casing surface, or some combination thereof.
Claim 21
Dependent Claim
29 words
The method of claim 16 wherein said borehole contains a casing is surrounded by an annulus of cement and said first radioactive material is deposited within the borehole region.
Claim 22
Dependent Claim
15 words
The method of claim 20 where said first material is uranium or its daughter products.
Claim 23
Dependent Claim
19 words
The method of claim 21 where said second and third materials the potassium, and thorium or its daughter products.
Claim 24
Dependent Claim
44 words
The method of claim 16 wherein said determining of elemental concentrations is from said formation spectrum and said sensitivity matrix element sets for said first, said second, and said third spectra, and wherein said second and third matrix elements are corrected for borehole effects.
Claim 25
Dependent Claim
11 words
The method of claim 16 wherein said first material is potassium.
Claim 26
Dependent Claim
21 words
The method of claim 24 wherein said second and third materials are radioisotopes of uranium and thorium and their daughter products.
Claim 27
Dependent Claim
27 words
The methods of claim 16 wherein said determining of anomalous deposition step is based on a comparison of a current and historical total natural gamma ray logs.
Claim 28
Dependent Claim
38 words
The method of claim 16 wherein said determining step utilizes the magnitude of the residual fitting error between the downhole spectrum and concentrations based on matrix elements derived for all three elements being uniformly distributed in the formation.
Claim 29
Dependent Claim
16 words
The method of claim 16 wherein said determining step uses a priori knowledge of anamolous deposition.
Claim 30
Dependent Claim
22 words
The method of claim 16 wherein variations in the photoelectrically sensitive casing ratio measurement R c are used to determine anomalous deposition.
Claim 31
Dependent Claim
22 words
The method of claim 15 wherein variations in photoelectrically-sensitive quantities are used to determine the proportion of anomalous deposition inside the casing.
Claim 32
Dependent Claim
25 words
The method of claim 30 which uses the residual fitting error in an iterative fashion to determine the proportions of anomalous deposition outside the casing.
Claim 33
Dependent Claim
18 words
The method of claim 31 wherein said first material is a radioisotope of uranium and its daughter products.
Claim 34
Dependent Claim
21 words
The method of claim 32 wherein said second and third materials are radioisotopes of potassium, and thorium and its daughter products.
Claim 35
Dependent Claim
36 words
The method of claim 31 wherein the borehole region in which the measurement is made contains a casing and first material is deposited on the inner casing surface, the outer casing surface, or some combination thereof.
Claim 36
Dependent Claim
28 words
The method of claim 31 wherein said borehole contains a casing surrounded by an annulus of cement and said first radioactive material is deposited within the borehole region.
Claim 37
Dependent Claim
15 words
The method of claim 35 where said first material is uranium or its daughter products.
Claim 38
Dependent Claim
19 words
The method of claim 36 where said second and third materials are potassium, and thorium or its daughter products.
Claim 39
Dependent Claim
44 words
The method of claim 31 wherein said determining of elemental concentrations is from said formation spectrum and said sensitivity matrix element sets for said first, said second, and said third spectra, and wherein said second and third matrix elements are corrected for borehole effects.
Claim 40
Dependent Claim
11 words
The method of claim 31 wherein said first material is potassium.
Claim 41
Dependent Claim
21 words
The method of claim 39 wherein said second and third materials are radioisotopes of uranium and thorium and their daughter products.
Claim 42
Dependent Claim
27 words
The method of claim 31 wherein said determining of anomalous deposition step is based on a comparison of a current and historical total natural gamma ray logs.
Claim 43
Dependent Claim
38 words
The method of claim 31 wherein said determining step utilizes the magnitude of the residual fitting error between the downhole spectrum and concentrations based on matrix elements derived for all three elements being uniformly distributed in the formation.
Claim 44
Dependent Claim
16 words
The method of claim 31 wherein said determining step uses a prior knowledge of anomalous deposition.
Claim 45
Dependent Claim
22 words
The method of claim 31 wherein variations in the photoelectrically sensitive casing ratio measurement R c are used to determine anomalous deposition.
Claim 46
Independent Claim
156 words
A method for compensating for anomalous radioactive deposition in the region of a borehole in determining subsurface earth formation natural radioactivity elemental concentrations, comprising: measuring a first reference spectrum of a first radioactive material simulating deposiition of said first material in the borehole region; measuring second, third and fourth reference spectra simulating deposition of second, third and fourth radioactive materials in the said formation, respectively; deriving a set of elemental determination sensitivity matrix elements based on each of said first, second, third and fourth reference spectra; measuring from within said borehole a downhole natural gamma ray energy spectrum of gamma rays originating in and traversing said borehole and formation; determining a condition of anomalous deposition of said first material in said borehole region; and calculating compensated elemental concentrations of said first, second, third and fourth materials from said downhole gamma ray spectrum, and said sensitivity matrix element sets for said first, second, third and fourth materials.
Claim 47
Independent Claim
156 words
A method for compensating for anomalous radioactive deposition in the region of a borehole in determining subsurface earth formation natural radioactivity elemental concentrations, comprising: measuring a first reference spectrum of a first radioactive material simulating deposiition of said first material in the borehole region; measuring second, third and fourth reference spectra simulating deposition of second, third and fourth radioactive materials in the said formation, respectively; deriving a set of elemental determination sensitivity matrix elements based on each of said first, second, third and fourth reference spectra; measuring from within said borehole a downhole natural gamma ray energy spectrum of gamma rays originating in and traversing said borehole and formation; determining a condition of anomalous deposition of said first material in said borehole region; and calculating compensated elemental concentrations of said first, second, third and fourth materials from said downhole gamma ray spectrum, and said sensitivity matrix element sets for said first, second, third and fourth materials.
Claim 48
Dependent Claim
19 words
The method of claim 45 wherein said first and third materials are radioisotopes of uranium and its daughter products.
Claim 49
Dependent Claim
21 words
The method of claim 46 wherein said second and fourth materials are radioisotopes of potassium, and thorium and its daughter products.
Claim 50
Dependent Claim
36 words
The method of claim 45 wherein the borehole region in which the measurement is made contains a casing and first material is deposited on the inner casing surface, the outer casing surface, or some combination thereof.
Claim 51
Dependent Claim
28 words
The method of claim 45 wherein said borehole contains a casing surrounded by an annulus of cement and said first radioactive material is deposited within the borehole region.
Claim 52
Dependent Claim
17 words
The method of claim 49 where said first and third materials are uranium or its daughter products.
Claim 53
Dependent Claim
19 words
The method of claim 50 where said second and fourth materials are potassium, and thorium or its daughter products.
Claim 54
Dependent Claim
47 words
The method of claim 45 wherein said determining of elemental concentrations is from said formation spectrum and said sensitivity matrix element sets for said first, said second, said third and said fourth spectra, and wherein said second third and fourth matrix elements are corrected for borehole effects.
Claim 55
Dependent Claim
11 words
The method of claim 45 wherein said first material is potassium.
Claim 56
Dependent Claim
25 words
The method of claim 53 wherein said second, third and fourth materials are radioisotopes of potassium and of uranium and thorium and their daugther products.
Claim 57
Dependent Claim
27 words
The method of claim 45 wherein said determining of anomalous deposition step is based on a comparison of a current and historical total natural gamma ray logs.
Claim 58
Dependent Claim
38 words
The method of claim 45 wherein said determining step utilizes the magnitude of the residual fittin error between the downhole spectrum and concentrations based on matrix elements derived for all three elements being uniformly distributed in the formation.
Claim 59
Dependent Claim
16 words
The method of claim 45 wherein said determining step uses a priori knowledge of anomalous deposition.
Claim 60
Dependent Claim
19 words
The method of claim 45 wherein said measurements are made and recorded continuously as a function of borehole depth.
Claim 61
Dependent Claim
25 words
The method of claim 45 wherein said anomalous deposition in said determination step utilizes a measurement of relative photoelectric attenuation of said observed downhole spectrum.
Claim 62
Dependent Claim
22 words
The method of claim 59 wherein variations in the photoelectrically sensitive casing ratio mmasurement R c are used to determine anomalous deposition.
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) | 1991-01-04 | 1991-07-06 | 1992-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-04 | 1995-07-06 | 1996-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-04 | 1999-07-06 | 2000-01-05 | $7700.00 | Window Closed / Lapsed |