Stabilized radioactive logging method and apparatus
An oil well logging apparatus is disclosed for detecting radiation emanating or returning from an oil well formation. The apparatus has a scintillation crystal adjacent a photomultiplier tube for detecting light flashes generated in the crystal by radiation. A low energy gamma source is included in the crystal for generating a known peak of pulse counts in the energy spectrum. A cadmium shield is placed over the crystal to block low energy radiation which would tend to mask the peak of gamma source pulses. This known peak is divided electrically downhole by window discriminators such that the peak is equally divided into two windows at a standard condition. If the frequency of pulses in one window varies from the frequency of pulses in the second window, a correction factor is generated downhole for varying the pulse height of the entire spectrum until the frequency of pulses in each window is again equal. Salinity compensation is also accomplished by samarium sleeves in the logging sonde.
- Assignee:
- Halliburton Co
- Patent Number(s):
- US 4300043
- OSTI ID:
- 5945032
- Country of Publication:
- United States
- Language:
- English
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Gain stabilization for radioactivity well logging apparatus
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Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
440400 -- Well Logging Instrumentation
47 OTHER INSTRUMENTATION
BOREHOLES
CADMIUM
CAVITIES
DESIGN
ELEMENTS
EQUIPMENT
GAMMA LOGGING
GAMMA SOURCES
MEASURING INSTRUMENTS
METALS
NAI DETECTORS
OIL WELLS
PHOTOMULTIPLIERS
PHOTOTUBES
PROBES
RADIATION DETECTORS
RADIATION SOURCES
RADIOACTIVITY LOGGING
RARE EARTHS
SAMARIUM
SCINTILLATION COUNTERS
SHIELDS
SLEEVES
SOLID SCINTILLATION DETECTORS
WELL LOGGING
WELL LOGGING EQUIPMENT
WELLS