Neutron logging method and apparatus for determining a formation characteristic free of environmental effects

Patent · Tue Dec 27 04:00:00 EST 1983

OSTI ID:7099547

Ellis, D V; Flaum, C

A method for determining porosity or other formation characteristic of a sub-surface geological formation traversed by a borehole is claimed. A neutron logging tool is passed through the borehole while irradiating the formation with neutrons. The neutron logging tool includes a neutron source and first and second detectors spaced from the source by different distances. Neutrons exiting the formation are detected with the neutron detectors and count rate signals are generated. In response to these signals, an indication of porosity, substantially independent of error due to tool standoff from said borehole wall, is produced. In addition, values of tool standoff are also generated. These standoff values are then filtered by a filter to reduce statistical variations and are used to generate improved indications of porosity.

• Assignee: Schlumberger Technology Corporation
• Patent Number(s): US 4423323
• OSTI ID: 7099547
• Country of Publication: United States
• Language: English

Related Subjects

440400* -- Well Logging Instrumentation
47 OTHER INSTRUMENTATION
BOREHOLES
CAVITIES
CONTROL
DESIGN
DETECTION
EQUIPMENT
EXPLORATORY WELLS
FUNCTIONS
GEOLOGIC DEPOSITS
GEOPHYSICAL SURVEYS
IRRADIATION
MEASURING INSTRUMENTS
NEUTRON DETECTION
NEUTRON LOGGING
NEUTRON SOURCES
PARTICLE SOURCES
POROSITY
PROCESS CONTROL
RADIATION DETECTION
RADIATION DETECTORS
RADIATION SOURCES
RADIOACTIVITY LOGGING
RESPONSE FUNCTIONS
SURVEYS
WELL LOGGING
WELL LOGGING EQUIPMENT
WELLS