US3654467A
Expired / Lapsed
US
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Transplutonium neutron activation logging technique
Assignee: Schlumberger Technology Corp
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Filing: 1969-05-12
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Granted: 1972-04-04
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Expires: 1989-05-12
Abstract
Abstract A typical embodiment of the invention enables neutrons of low average energy that characteristically are emitted from californium 252 (Cf252) to react with, or fail to react with, nuclei within an earth formation, depending on the energy threshold for the reaction in question. The neutron activation induced by means of the Cf252 source is compared with the response induced in the formation through neutrons of higher average energies from other sources, The activation comparison permits the identification of elements and minerals in the formation to be determined accurately.
Inventors
- 👤 Jay Tittman
- 👤 William B Nelligan
- 👤 John S Wahl
- 👤 Harold Sherman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:07
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04; G01V5/08; G01V5/10; G01V5/101
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
14 words
A logging system according to claim 1 wherein said neutron source comprises californium 252.
Claim 2
Dependent Claim
128 words
An earth formation logging system comprising, a transplutonium neutron source for emitting neutrons for thermal absorption in sodium, detector means responsive to the neutrons in the earth formation that are emitted from said source, circuit means responsive to said detector means for producing a signal that identifies nuclear reactions between said sodium and neutrons emitted from said transplutonium source, another neutron source for emitting neutrons of an average energy that is different from the average energy characterizing said transplutonium neutron source, and a circuit for producing a signal that characterizes the earth formation response to neutrons emitted from said another neutron source for comparison with said transplutonium neutron signal in order to identify more clearly the nuclear reactions between said sodium and neutrons emitted from said transplutonium source.
Claim 3
Dependent Claim
27 words
A system according to claim 9 further comprising additional circuit means for energizing said another neutron source to produce pulses of neutrons that are spaced in time.
Claim 4
Dependent Claim
29 words
A system according to claim 4 wherein said comparison circuit further comprises means for identifying the earth formation chlorine concentration and contrasting said chlorine concentration with said sodium signal.
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) | 1975-04-04 | 1975-10-04 | 1976-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-04 | 1979-10-04 | 1980-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-04 | 1983-10-04 | 1984-04-04 | $7700.00 | Window Closed / Lapsed |