US4439676A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Natural gamma ray logging with borehole effect compensation
Assignee: Texaco Inc
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Filing: 1981-06-05
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Granted: 1984-03-27
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Expires: 2001-06-05
Abstract
Abstract A natural gamma ray logging system utilizes gamma ray spectroscopy to measure thorium, uranium and potassium content of earth formations adjacent a well borehole. An additional measurement is also taken from which compensation for borehole effects on the measurements of interest is achieved.
Inventors
- 👤 Harry D. Smith, Jr.
- 👤 Dan M. Arnold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:28
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04; G01V5/06
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
169 words
A method of natural gamma ray logging of subsurface formations adjacent a well borehole with a detector in a sonde, while compensating for the effects of borehole conditions on the logging, comprising the steps of: (a) measuring natural gamma radiation from the formation in a first energy window containing the 2.61 MeV thorium energy peak; (b) measuring natural gamma radiation from the formation in a second energy window containing the 1.76 MeV uranium energy peak; (c) measuring natural gamma radiation from the formation in a third energy window containing the 1.46 MeV potassium energy peak; (d) measuring natural gamma radiation in the formation in a fourth energy window differing at least in part from the other three energy windows; and (e) obtaining from the gamma radiation measured in the four energy windows and stripping constants from calibration formations a compensating function indicative of the effects of borehole conditions on the gamma radiation measured; (f) adjusting the measured natural gamma radiation for different borehole conditions based on the compensating function.
Claim 2
Independent Claim
169 words
A method of natural gamma ray logging of subsurface formations adjacent a well borehole with a detector in a sonde, while compensating for the effects of borehole conditions on the logging, comprising the steps of: (a) measuring natural gamma radiation from the formation in a first energy window containing the 2.61 MeV thorium energy peak; (b) measuring natural gamma radiation from the formation in a second energy window containing the 1.76 MeV uranium energy peak; (c) measuring natural gamma radiation from the formation in a third energy window containing the 1.46 MeV potassium energy peak; (d) measuring natural gamma radiation in the formation in a fourth energy window differing at least in part from the other three energy windows; and (e) obtaining from the gamma radiation measured in the four energy windows and stripping constants from calibration formations a compensating function indicative of the effects of borehole conditions on the gamma radiation measured; (f) adjusting the measured natural gamma radiation for different borehole conditions based on the compensating function.
Claim 3
Dependent Claim
22 words
The method of claim 1, further including the step of: displaying the compensating function as a function of depth in the borehole.
Claim 4
Dependent Claim
60 words
The method of claim 1, further including the step of: (a) obtaining a measure of elemental concentration of thorium based on natural gamma radiation measured in the energy windows; (b) obtaining a correction factor for borehole effects on the elemental concentration measure of thorium in the formation; (c) compensating the elemental concentration measure of thorium according to the correction factor.
Claim 5
Dependent Claim
26 words
The method of claim 3, further including the step of: displaying the compensated elemental concentration measure of thorium as a function of depth in the borehole.
Claim 6
Dependent Claim
61 words
The method of claim 1, further including the step of: (a) obtaining a measure of elemental concentration of uranium based on natural gamma radiation measured in the energy windows; (b) obtaining a correction factor for borehole effects on the elemental concentration measure of uranium in the formation; and (c) compensating the elemental concentration measure of uranium according to the correction factor.
Claim 7
Dependent Claim
26 words
The method of claim 5, further including the step of: displaying the compensated elemental concentration measure of uranium as a function of depth in the borehole.
Claim 8
Dependent Claim
62 words
The method of claim 1, further including the step of: (a) obtaining a measure of elemental concentration of potassium based on a natural gamma radiation measured in the energy windows; (b) obtaining a correction factor for borehole effects on the elemental concentration measure of potassium in the formation; and (c) compensating the elemental concentration measure of potassium according to the correction factor.
Claim 9
Dependent Claim
26 words
The method of claim 7, further including the step of: displaying the compensated elemental concentration measure of potassium as a function of depth in the borehole.
Claim 10
Independent Claim
176 words
A method of natural gamma ray logging of subsurface formations adjacent a well borehole with a detector in a sonde, while compensating for the effects of borehole conditions on the logging, comprising the steps of: (a) measuring natural gamma radiation from the formation in a first energy window containing the 2.61 MeV thorium energy peak; (b) measuring natural gamma radiation from the formation in a second energy window containing the 1.76 MeV uranium energy peak; (c) measuring natural gamma radiation from the formation in a third energy window containing the 1.46 MeV potassium energy peak; (d) measuring natural gamma radiation in the formation in a fourth energy window differing at least in part from the other three energy windows; and (e) obtaining a measure of elemental concentration of thorium based on natural gamma radiation measured in the energy windows and stripping constants from calibration formations; (f) obtaining a correction factor for borehole effects on the elemental concentration measure of thorium in the formation; (g) compensating the elemental concentration measure of thorium according to the correction factor.
Claim 11
Independent Claim
176 words
A method of natural gamma ray logging of subsurface formations adjacent a well borehole with a detector in a sonde, while compensating for the effects of borehole conditions on the logging, comprising the steps of: (a) measuring natural gamma radiation from the formation in a first energy window containing the 2.61 MeV thorium energy peak; (b) measuring natural gamma radiation from the formation in a second energy window containing the 1.76 MeV uranium energy peak; (c) measuring natural gamma radiation from the formation in a third energy window containing the 1.46 MeV potassium energy peak; (d) measuring natural gamma radiation in the formation in a fourth energy window differing at least in part from the other three energy windows; and (e) obtaining a measure of elemental concentration of thorium based on natural gamma radiation measured in the energy windows and stripping constants from calibration formations; (f) obtaining a correction factor for borehole effects on the elemental concentration measure of thorium in the formation; (g) compensating the elemental concentration measure of thorium according to the correction factor.
Claim 12
Dependent Claim
26 words
The method of claim 9, further including the step of: displaying the compensated elemental concentration measure of thorium as a function of depth in the borehole.
Claim 13
Independent Claim
171 words
A method of natural gamma ray logging of subsurface formations adjacent a well borehole with a detector in a sonde, while compensating for the effects of borehole conditions on the logging, comprising the steps of: (a) measuring natural gamma radiation from the formation in a first energy window containing the 2.61 MeV thorium energy peak; (b) measuring natural gamma radiation from the formation in a second energy window containing the 1.76 MeV uranium energy peak; (c) measuring natural gamma radiation from the formation in a third energy window containing the 1.46 MeV potassium energy peak; (d) measuring natural gamma radiation in the formation in a fourth energy window differing at least in part from the other three energy windows; and (e) obtaining a measure of elemental concentration of uranium based on natural gamma radiation measured in the energy windows; (f) obtaining a correction factor for borehole effects on the elemental concentration measure of uranium in the formation; and (g) compensating the elemental concentration measure of uranium according to the correction factor.
Claim 14
Independent Claim
171 words
A method of natural gamma ray logging of subsurface formations adjacent a well borehole with a detector in a sonde, while compensating for the effects of borehole conditions on the logging, comprising the steps of: (a) measuring natural gamma radiation from the formation in a first energy window containing the 2.61 MeV thorium energy peak; (b) measuring natural gamma radiation from the formation in a second energy window containing the 1.76 MeV uranium energy peak; (c) measuring natural gamma radiation from the formation in a third energy window containing the 1.46 MeV potassium energy peak; (d) measuring natural gamma radiation in the formation in a fourth energy window differing at least in part from the other three energy windows; and (e) obtaining a measure of elemental concentration of uranium based on natural gamma radiation measured in the energy windows; (f) obtaining a correction factor for borehole effects on the elemental concentration measure of uranium in the formation; and (g) compensating the elemental concentration measure of uranium according to the correction factor.
Claim 15
Dependent Claim
26 words
The method of claim 11, further including the step of: displaying the compensated elemental concentration measure of uranium as a function of depth in the borehole.
Claim 16
Independent Claim
172 words
A method of natural gamma ray logging of subsurface formations adjacent a well borehole with a detector in a sonde, while compensating for the effects of borehole conditions on the logging, comprising the steps of: (a) measuring natural gamma radiation from the formation in a first energy window containing the 2.61 MeV thorium energy peak; (b) measuring natural gamma radiation from the formation in a second energy window containing the 1.76 MeV uranium energy peak; (c) measuring natural gamma radiation from the formation in a third energy window containing the 1.46 MeV potassium energy peak; (d) measuring natural gamma radiation in the formation in a fourth energy window differing at least in part from the other three energy windows; and (e) obtaining a measure of elemental concentration or potassium based on a natural gamma radiation measured in the energy windows; (f) obtaining a correction factor for borehole effects on the elemental concentration measure of potassium in the formation; and (g) compensating the elemental concentration measure of potassium according to the correction factor.
Claim 17
Independent Claim
172 words
A method of natural gamma ray logging of subsurface formations adjacent a well borehole with a detector in a sonde, while compensating for the effects of borehole conditions on the logging, comprising the steps of: (a) measuring natural gamma radiation from the formation in a first energy window containing the 2.61 MeV thorium energy peak; (b) measuring natural gamma radiation from the formation in a second energy window containing the 1.76 MeV uranium energy peak; (c) measuring natural gamma radiation from the formation in a third energy window containing the 1.46 MeV potassium energy peak; (d) measuring natural gamma radiation in the formation in a fourth energy window differing at least in part from the other three energy windows; and (e) obtaining a measure of elemental concentration or potassium based on a natural gamma radiation measured in the energy windows; (f) obtaining a correction factor for borehole effects on the elemental concentration measure of potassium in the formation; and (g) compensating the elemental concentration measure of potassium according to the correction factor.
Claim 18
Dependent Claim
26 words
The method of claim 13, further including the step of: displaying the compensated elemental concentration measure of potassium as a function of depth in the borehole.
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) | 1987-03-27 | 1987-09-26 | 1988-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-27 | 1991-09-26 | 1992-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-27 | 1995-09-26 | 1996-03-27 | $7700.00 | Window Closed / Lapsed |