US4378498A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Simulation of subsurface formations for the testing and calibration of radioactive well logging tools
Assignee: Mobil Oil AS
•
Filing: 1980-10-07
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Granted: 1983-03-29
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Expires: 2000-10-07
Abstract
Abstract A radioactive medium simulates a desired subsurface formation condition for the testing and calibration of radioactive well logging tools. The medium simulates a state of radioactive equilibrium in which the decay products of the parent isotope decay at a desired rate to that at which they are produced within the medium.
Inventors
- 👤 Wyatt W. Givens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:06
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
101 words
A method of testing a uranium assay logging tool, comprising the steps of; (a) providing a refined uranium bearing medium of suitable thickness to simulate the condition of the uranium content of a subsurface formation, (b) adding radium to said medium to achieve a desired state of apparent radioactive equilibrium between said refined uranium and its decay products lead and bismuth which emit the abundance of gamma-rays associated with a natural uranium ore, (c) exposing said logging tool to the radioactive radiation of the medium, and (d) measuring the response of said logging tool to said radioactive radiation from said medium.
Claim 2
Independent Claim
101 words
A method of testing a uranium assay logging tool, comprising the steps of; (a) providing a refined uranium bearing medium of suitable thickness to simulate the condition of the uranium content of a subsurface formation, (b) adding radium to said medium to achieve a desired state of apparent radioactive equilibrium between said refined uranium and its decay products lead and bismuth which emit the abundance of gamma-rays associated with a natural uranium ore, (c) exposing said logging tool to the radioactive radiation of the medium, and (d) measuring the response of said logging tool to said radioactive radiation from said medium.
Claim 3
Dependent Claim
53 words
The method of claim 1 wherein the amount of radium added to said uranium bearing medium provides a state of apparent equilibrium in which said decay products of the parent uranium content of said medium are decaying at substantially the same rate of that at which they are being produced by said medium.
Claim 4
Dependent Claim
50 words
The method of claim 1 wherein the amount of radium added to said uranium bearing medium provides a state of apparent equilibrium in which said decay products of the parent uranium content of said medium are decaying at a rate in excess of that at which they are being produced.
Claim 5
Dependent Claim
49 words
The method of claim 1 wherein the amount of radium added to said uranium bearing medium provides a state of apparent equilibrium in which said decay products of the parent uranium content of said medium are decaying at a rate less than that at which they are being produced.
Claim 6
Dependent Claim
39 words
The method of claim 1 wherein the amount of radium added to said uranium bearing medium is sufficient to permit the neutron and gamma ray measurements of said logging tool to be representative of substantially the same ore grade.
Claim 7
Independent Claim
82 words
A method of testing a borehole logging tool adapted to respond to the uranium content of the subsurface formations surrounding a borehole, comprising the steps of: (a) exposing said borehole logging tool to a uranium bearing medium of suitable thickness to simulate a subsurface condition surrounding a borehole in which a uranium parent and its decay products, lead and bismuth, are in a desired state of apparent radioactive equilibrium, and (b) measuring the response of said borehole logging tool to said medium.
Claim 8
Independent Claim
82 words
A method of testing a borehole logging tool adapted to respond to the uranium content of the subsurface formations surrounding a borehole, comprising the steps of: (a) exposing said borehole logging tool to a uranium bearing medium of suitable thickness to simulate a subsurface condition surrounding a borehole in which a uranium parent and its decay products, lead and bismuth, are in a desired state of apparent radioactive equilibrium, and (b) measuring the response of said borehole logging tool to said medium.
Claim 9
Dependent Claim
12 words
The method of claim 6 wherein said radioactive parent is refined uranium.
Claim 10
Dependent Claim
14 words
The method of claim 7 wherein radium is added to said uranium bearing medium.
Claim 11
Dependent Claim
15 words
The method of claim 8 wherein the weight ratio of uranium to radium is unity.
Claim 12
Dependent Claim
17 words
The method of claim 8 wherein the weight ratio of uranium to radium is less than unity.
Claim 13
Dependent Claim
17 words
The method of claim 8 wherein the weight ratio of uranium to radium is greater than unity.
Claim 14
Independent Claim
84 words
A method of simulating the radioactivity condition of a subsurface formation surrounding a borehole, comprising the steps of: (a) adding refined uranium to a medium of suitable thickness to simulate the condition of a subsurface formation, and (b) adding radium to said medium to achieve a desired state of apparent radioactive equilibrium in which the end decay products of the parent uranium content of said medium are decaying at a desired rate relative to that at which they are being produced within said medium.
Claim 15
Independent Claim
84 words
A method of simulating the radioactivity condition of a subsurface formation surrounding a borehole, comprising the steps of: (a) adding refined uranium to a medium of suitable thickness to simulate the condition of a subsurface formation, and (b) adding radium to said medium to achieve a desired state of apparent radioactive equilibrium in which the end decay products of the parent uranium content of said medium are decaying at a desired rate relative to that at which they are being produced within said medium.
Claim 16
Dependent Claim
12 words
The method of claim 12 wherein said uranium is a soluble compound.
Claim 17
Dependent Claim
12 words
The method of claim 12 wherein said uranium is a uranyl nitrate.
Claim 18
Dependent Claim
14 words
The method of claim 12 wherein said uranium contains natural abundance of uranium-238 isotopes.
Claim 19
Dependent Claim
14 words
The method of claim 12 wherein said uranium contains natural abundance of uranium-235 isotopes.
Claim 20
Dependent Claim
12 words
The method of claim 12 wherein said radium is a soluble compound.
Claim 21
Dependent Claim
12 words
The method of claim 12 wherein said radium is a radium bromide.
Claim 22
Dependent Claim
11 words
The method of claim 12 wherein said radium contains radium-226 isotopes.
Claim 23
Dependent Claim
14 words
The method of claim 12 wherein said end decay products are bismuth and lead.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-28 | 1986-09-27 | 1987-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-28 | 1990-09-27 | 1991-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-28 | 1994-09-27 | 1995-03-29 | $7700.00 | Window Closed / Lapsed |