US4780679A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for determining low frequency conductivity of subsurface formations
Assignee: Schlumberger Technology Corp
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Filing: 1987-02-02
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Granted: 1988-10-25
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Expires: 2007-02-02
Abstract
Abstract Well logging techniques are set forth for obtaining improved measurements of formation dielectric permittivity, conductivity, and water-filled porosity. The effects of dielectric and conductivity frequency dispersion are considered and utilized. In a disclosed embodiment, an estimated low frequency conductivity of a formation surrounding a borehole is determined using the following steps: deriving a measured value of formation high frequency conductivity from a logging device which traversed the borehole; determining a formation conductivity dispersion ratio as a function of the measured conductivity; and determining an estimated low frequency conductivity from the measured value of high frequency conductivity and the dispersion ratio.
Inventors
- 👤 William E. Kenyon
- 👤 Paul L. Baker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:50
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/18; G01V3/26; G01V3/28; G01V3/38
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
68 words
A method for determining an estimated low frequency conductivity of a formation surrounding a borehole, comprising the steps of: deriving a measured value of formation high frequency conductivity from a logging device which traversed the borehole; determining a formation conductivity dispersion ratio as a function of the measured conductivity; and determining an estimated low frequency conductivity from said measured value of high frequency conductivity and said dispersion ratio.
Claim 2
Independent Claim
68 words
A method for determining an estimated low frequency conductivity of a formation surrounding a borehole, comprising the steps of: deriving a measured value of formation high frequency conductivity from a logging device which traversed the borehole; determining a formation conductivity dispersion ratio as a function of the measured conductivity; and determining an estimated low frequency conductivity from said measured value of high frequency conductivity and said dispersion ratio.
Claim 3
Dependent Claim
38 words
The method as defined by claim 1, wherein said step of determining an estimated low frequency conductivity from said measured value of high frequency conductivity and said dispersion ratio comprises dividing said measured value by said dispersion ratio.
Claim 4
Dependent Claim
47 words
The method as defined by claim 1, further comprising the step of storing a predetermined conductivity dispersion ratio function for the formation, as a function of conductivity, and wherein said formation conductivity dispersion ratio is determined from said predetermined conductivity dispersion ratio function and said measured conductivity.
Claim 5
Dependent Claim
47 words
The method as defined by claim 2, further comprising the step of storing a predetermined conductivity dispersion ratio function for the formation, as a function of conductivity, and wherein said formation conductivity dispersion ratio is determined from said predetermined conductivity dispersion ratio function and said measured conductivity.
Claim 6
Dependent Claim
25 words
The method as defined by claim 1, wherein said predetermined conductivity dispersion ratio function for the formation is a function of frequency divided by conductivity.
Claim 7
Dependent Claim
25 words
The method as defined by claim 2, wherein said predetermined conductivity dispersion ratio function for the formation is a function of frequency divided by conductivity.
Claim 8
Dependent Claim
25 words
The method as defined by claim 3, wherein said predetermined conductivity dispersion ratio function for the formation is a function of frequency divided by conductivity.
Claim 9
Dependent Claim
29 words
The method as defined by claim 2, wherein said measured value of formation high frequency conductivity and the determined estimated low frequency conductivity are for the formation invaded zone.
Claim 10
Dependent Claim
29 words
The method as defined by claim 4, wherein said measured value of formation high frequency conductivity and the determined estimated low frequency conductivity are for the formation invaded zone.
Claim 11
Dependent Claim
46 words
The method as defined by claim 1, further comprising the steps of deriving a measured value of low frequency conductivity from a logging device which traversed the borehole; and comparing said measured value of low frequency conductivity to said determined estimated value of low frequency conductivity.
Claim 12
Dependent Claim
46 words
The method as defined by claim 9, further comprising the steps of deriving a measured value of low frequency conductivity from a logging device which traversed the borehole; and comparing said measured value of low frequency conductivity to said determined estimated value of low frequency conductivity.
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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) | 1991-10-25 | 1992-04-25 | 1992-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-25 | 1996-04-25 | 1996-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-25 | 2000-04-25 | 2000-10-25 | $7700.00 | Window Closed / Lapsed |