Neutron--neutron logging for both porosity and macroscopic absorption cross section

Patent · Tue May 03 04:00:00 EDT 1977

OSTI ID:7213035

Allen, L S

A borehole logging tool includes a fast neutron source and at least two thermal neutron detectors spaced apart from the source. A count rate meter is connected to each thermal neutron detector. A ratio detector provides an indication of the porosity of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters. A comparison unit provides a signal indicative of the macroscopic absorption cross section of the formation by comparing the indicated porosity with at least one of the count rate signals. 9 claims, 2 figures.

• Assignee: Mobil Oil Corp.
• Patent Number(s): US 4021666
• OSTI ID: 7213035
• Country of Publication: United States
• Language: English

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46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
47 OTHER INSTRUMENTATION
BARYONS
BOREHOLES
CAVITIES
COUNTING RATEMETERS
CROSS SECTIONS
ELECTRONIC EQUIPMENT
ELEMENTARY PARTICLES
EQUIPMENT
FAST NEUTRONS
FERMIONS
HADRONS
MEASURING INSTRUMENTS
NEUTRON DETECTORS
NEUTRON LOGGING
NEUTRON SOURCES
NEUTRON-NEUTRON LOGGING
NEUTRONS
NUCLEONS
PARTICLE SOURCES
POROSITY
RADIATION DETECTORS
RADIATION SOURCES
RADIOACTIVITY LOGGING
WELL LOGGING