Method and apparatus for neutron induced gamma ray logging for direct porosity identification

Patent · Mon Feb 06 23:00:00 EST 1984

OSTI ID:6785333

Oliver, D W; Chace, D M

In a gamma ray well logging instrument, a neutron generator is pulsed at a predetermined rate. Each neutron burst produces gamma radiation resulting from inelastic scattering and neutron capture. The detected gamma radiations are detected by a detector system within the logging instrument. The detected pulses are transmitted to the surface electronics where pulses occurring in the inelastic interval are directed to one section of a multi-channel analyzer and pulses from the capture interval are directed to another section of the analyzer. The use of address decoders and ratio circuits enables an electrical signal to be obtained which represents the ratio of the total capture gamma ray counts within an energy range to the total inelastic gamma ray counts within the same energy range. This electrical signal is representative of the porosity of the subsurface formations being irradiated by neutrons.

• Assignee: Dresser Industries, Inc.
• Patent Number(s): US 4430567
• OSTI ID: 6785333
• Country of Publication: United States
• Language: English

Related Subjects

440400* -- Well Logging Instrumentation
47 OTHER INSTRUMENTATION
ACCURACY
BARYON REACTIONS
CAPTURE
COMMUNICATIONS
DATA TRANSMISSION
DESIGN
DISCRIMINATORS
ELECTROMAGNETIC RADIATION
ELECTRONIC CIRCUITS
ELECTRONIC EQUIPMENT
EQUIPMENT
GAMMA RADIATION
GEOLOGIC FORMATIONS
HADRON REACTIONS
INELASTIC SCATTERING
IONIZING RADIATIONS
LOGIC CIRCUITS
MEASURING METHODS
MULTI-CHANNEL ANALYZERS
NEUTRON LOGGING
NEUTRON REACTIONS
NEUTRON SOURCES
NEUTRON-GAMMA LOGGING
NUCLEAR REACTIONS
NUCLEON REACTIONS
PARTICLE SOURCES
POROSITY
PULSE ANALYZERS
PULSE TECHNIQUES
RADIATION SOURCES
RADIATIONS
RADIOACTIVITY LOGGING
RELIABILITY
SCATTERING
TELEMETRY
WELL LOGGING
WELL LOGGING EQUIPMENT