US3586858A
Expired / Lapsed
US
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Permeability measuring system
Assignee: Western Atlas International Inc
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Filing: 1968-01-17
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Granted: 1971-06-22
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Expires: 1988-01-17
Abstract
Abstract This system permits the measurement of permeability of subsurface formations in situ injecting a neutron absorber fluid and observing the progressive change in the thermal neutron absorption cross section.
Inventors
- 👤 Arthur H Youmans
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:34
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04; G01V5/08; G01V5/10; G01V5/101; G01V5/102
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
109 words
A method of measuring the character of a selected formation penetrated by a borehole, comprising: measuring the thermal neutron absorption cross section of said formation; injecting a liquid having a predetermined thermal neutron absorption cross section into said formation; measuring the thermal neutron absorption cross section of said formation; and determining a value for permeability in accordance with the equation: where K2 is a constant, P is the differential pressure between that in the borehole and that in the formation, Sigma is thermal neutron absorption cross section, and T2 and T1 are the times at which the measurements of Sigma are made, both being substantially before equilibrium is attained.
Claim 2
Dependent Claim
35 words
A method of measuring the character of a selected formation as set forth in claim 2 wherein said predetermined thermal neutron absorption cross section of said liquid is different from that measured for said formation.
Claim 3
Dependent Claim
78 words
A method of measuring the character of a selected formation as set forth in claim 2 wherein the value of the thermal neutron absorption cross section is determined in accordance with the equation: Sigma (C/ Delta T) ln (N1/N2) where N1 and N2 are the conts detected, respectively, during two separate measuring intervals, Delta T is the elapsed time between the beginning of the first interval and the beginning of the second interval, And C is a constant.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-21 | 1974-12-21 | 1975-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-21 | 1978-12-21 | 1979-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-21 | 1982-12-21 | 1983-06-22 | $7700.00 | Window Closed / Lapsed |