Dual spaced epithermal neutron detector porosity logging with AcBe source

Patent · Tue Sep 16 04:00:00 EDT 1975

OSTI ID:4192141

Scott, H D; Smith, M P

An illustrative embodiment of the invention includes method and apparatus for making earth formation porosity measurements in open or cased well boreholes. A relatively high intensity (10$sup 8$ neutrons/sec) actinium- beryllium neutron source is used to irradiate earth formations surrounding a well borehole with high energy neutrons. As the high energy neutrons interact with the materials comprising the earth formation their energy is reduced and some having epithermal energy are deflected back into the borehole at spaced distances from the neutron source. Two epithermal energy neutron detectors spaced at different vertical distances from the neutron source and from each other are used to measure the epithermal neutron population at the different distances. The ratio of the counting rates in the two detectors may be interpreted in terms of earth formation porosity by means of a predetermined relationship. (auth)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-33-000793
• Assignee: to Texaco Inc.
• Patent Number(s): US 3906224
• OSTI ID: 4192141
• Country of Publication: United States
• Language: English

Related Subjects

*POROSIMETERS-- DESIGN
*SOILS-- POROSITY
*WELL LOGGING-- POROSIMETERS
440105* --Instrumentation--Radiation Instrumentation-- Radiometric Instruments
ACTINIUM
BERYLLIUM
EPITHERMAL NEUTRONS
N44410 - -Environmental & Earth Sciences--Radiometric Techniques--Atmosphere
N46200* --Instrumentation--Radiometric Instruments
NEUTRON SOURCES