Patent US5086224A successfully refreshed from Google Patents.
US5086224A
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Analysis of nuclear data for determining characteristics of earth formations traversed by a borehole
Assignee: Schlumberger Technology Corp
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Filing: 1990-11-13
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Granted: 1992-02-04
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Expires: 2010-11-13
Abstract
Abstract A method for the determination of petrophysical characteristics of earth formation surrounding a borehole, comprising detecting gamma rays or neutrons representative of the formations and forming therefrom a set of detected data "U" which is then expressed as a function of the unknown characteristics "Y", and of a set of response data "S", representative of the conditions under which the detecting step is performed; and wherein "Y" is expressed as r=R Y, where "r" represents prior information independent from the detected data and obtained from other sources, and "R" indicates a set of relationships between at least part of the unknown characteristics. The detected data and response data are e.g. in the form of spectra, and the method may further include irradiating the formation with neutrons or gama rays.
Inventors
- 👤 Bradley A. Roscoe
- 👤 Michael L. Evans
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:12
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04; G01V5/08; G01V5/10; G01V5/104; G01V5/101; G01V5/107
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
103 words
A method for the determination of petrophysical characteristics of earth formation surrounding a borehole, comprising: detecting nuclear particles representative of said formations and forming therefrom a set of detected data; expressing said set of detected data "U" as a function of said unknown characteristics "Y", and of a set of response data "S", representative of the conditions under which said detecting step is performed; and expressing said unknown characteristics "Y" as r=Y R, where "r" represents prior information independent from said detected data and obtained from other sources, and "R" indicates a set of relationships between at least part of said unknown characteristics.
Claim 2
Independent Claim
103 words
A method for the determination of petrophysical characteristics of earth formation surrounding a borehole, comprising: detecting nuclear particles representative of said formations and forming therefrom a set of detected data; expressing said set of detected data "U" as a function of said unknown characteristics "Y", and of a set of response data "S", representative of the conditions under which said detecting step is performed; and expressing said unknown characteristics "Y" as r=Y R, where "r" represents prior information independent from said detected data and obtained from other sources, and "R" indicates a set of relationships between at least part of said unknown characteristics.
Claim 3
Dependent Claim
19 words
The method according to claim 1 wherein said detected data and response data are in the form of spectra.
Claim 4
Dependent Claim
37 words
The method according to claim 1 further including the step of irradiating said formation with nuclear particles, such as neutrons, gamma rays or X-rays, by means of a source disposed in a sonde lowered in said borehole.
Claim 5
Dependent Claim
31 words
The method according to claim 1 wherein said prior information comprises the borehole size, borehole fluid salinity, mudcake physical properties, formation lithology, porosity, casing parameters, mud characteristics or any combination thereof.
Claim 6
Dependent Claim
27 words
The method according to claim 1 wherein said prior information comprises measurements related to at least one of said unknown characteristics and independent from said detected data.
Claim 7
Independent Claim
128 words
A method for decomposing a gamma ray spectrum representative of earth formation surrounding a borehole, in order to determine the respective gamma ray contribution of each constituents postulated to constitute said formation, comprising: detecting and counting the gamma rays issued and representative from said formation; forming an energy spectrum of said detected gamma rays; establishing a composite spectrum made up of individual standard spectra of said postulated constituents and comprising elemental yields, each elemental yield being representative of the proportion of a given constituent; expressing the elemental yields as a function of prior information independent from said detected spectrum, and of a prior information response matrix made of individual elemental responses of said prior information; and determining the best fit between said detected spectrum and said composite spectrum.
Claim 8
Independent Claim
128 words
A method for decomposing a gamma ray spectrum representative of earth formation surrounding a borehole, in order to determine the respective gamma ray contribution of each constituents postulated to constitute said formation, comprising: detecting and counting the gamma rays issued and representative from said formation; forming an energy spectrum of said detected gamma rays; establishing a composite spectrum made up of individual standard spectra of said postulated constituents and comprising elemental yields, each elemental yield being representative of the proportion of a given constituent; expressing the elemental yields as a function of prior information independent from said detected spectrum, and of a prior information response matrix made of individual elemental responses of said prior information; and determining the best fit between said detected spectrum and said composite spectrum.
Claim 9
Dependent Claim
31 words
The method according to claim 6 wherein said prior information comprises the borehole size, borehole fluid salinity, mudcake physical properties, formation lithology, porosity, mud and/or casing characteristics, or any combination thereof.
Claim 10
Dependent Claim
13 words
The method according to claim 1 wherein said detected particles are gamma rays.
Claim 11
Independent Claim
108 words
An apparatus for the determination of petrophysical characteristics of earth formation surrounding a borehole, comprising: means for detecting nuclear particles representative of said formations and forming therefrom a set of detected data; means for expressing said set of detected data "U" as a function of said unknown characteristics "Y", and of a set of response data "S", representative of the conditions under which said detecting means operates; and means for expressing said unknown characteristics "Y" as r=Y R, where "r" represents prior information independent from said detected data and obtained from other sources, and "R" indicates a set of relationships between at least part of said unknown characteristics.
Claim 12
Independent Claim
108 words
An apparatus for the determination of petrophysical characteristics of earth formation surrounding a borehole, comprising: means for detecting nuclear particles representative of said formations and forming therefrom a set of detected data; means for expressing said set of detected data "U" as a function of said unknown characteristics "Y", and of a set of response data "S", representative of the conditions under which said detecting means operates; and means for expressing said unknown characteristics "Y" as r=Y R, where "r" represents prior information independent from said detected data and obtained from other sources, and "R" indicates a set of relationships between at least part of said unknown characteristics.
Claim 13
Dependent Claim
35 words
The apparatus according to claim 9 further comprising means for irradiating said formation with nuclear particles, such as neutrons or gamma rays, by means of a source disposed in a sonde lowered in said borehole.
Claim 14
Dependent Claim
12 words
The apparatus according to claim 10 wherein said irradiating particles are neutrons.
Claim 15
Independent Claim
136 words
An apparatus for decomposing a gamma ray spectrum representative of earth formation surrounding a borehole, in order to determine the respective gamma ray contribution of each constituents postulated to constitute said formation, comprising: means for detecting and counting the gamma rays issued from said formation; means for forming an energy spectrum of said detected gamma rays; means for establishing a composite spectrum made up of individual standard spectra of said postulated constituents and comprising elemental yields, each elemental yield being representative of the proportion of a given constituent; means for expressing the elemental yields as a function of prior information, independent from said detected spectrum, and of a prior information response matrix made of individual elemental responses of said prior information; and means for determining the best fit between said detected spectrum and said composite spectrum.
Claim 16
Independent Claim
136 words
An apparatus for decomposing a gamma ray spectrum representative of earth formation surrounding a borehole, in order to determine the respective gamma ray contribution of each constituents postulated to constitute said formation, comprising: means for detecting and counting the gamma rays issued from said formation; means for forming an energy spectrum of said detected gamma rays; means for establishing a composite spectrum made up of individual standard spectra of said postulated constituents and comprising elemental yields, each elemental yield being representative of the proportion of a given constituent; means for expressing the elemental yields as a function of prior information, independent from said detected spectrum, and of a prior information response matrix made of individual elemental responses of said prior information; and means for determining the best fit between said detected spectrum and said composite spectrum.
Claim 17
Dependent Claim
32 words
The apparatus according to claim 9 wherein said prior information comprises the borehole size, borehole fluid salinity, mudcake physical properties, formation lithology, porosity, or mud and/or casing parameters or any combination thereof.
Claim 18
Dependent Claim
28 words
The apparatus according to claim 12 wherein said prior information comprises the borehole size, borehole fluid salinity, mudcake physical properties, formation lithology, or porosity, or any combination thereof.
Claim 19
Dependent Claim
13 words
The apparatus according to claim 9 wherein said detected particles are gamma rays.
Claim 20
Dependent Claim
11 words
The apparatus according to claim 9 further comprising a neutron source.
Claim 21
Dependent Claim
11 words
The apparatus according to claim 12 further comprising a neutron source.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1995-02-03 | 1995-08-05 | 1996-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-02-03 | 1999-08-05 | 2000-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-02-03 | 2003-08-05 | 2004-02-04 | $7700.00 | Window Closed / Lapsed |