multi-sensor gamma ray tool
TRANSCRIPT
Description
ApplicationsSchematic diagram of the Multi-Sensor Gamma Ray Tool.
Specifications
ODP Logging Services, Lamont-Doherty Earth Observatory, Rt. 9W, Palisades, NY 10964
Multi-Sensor GammaRay Tool
Logs from the MGT show more finely layered structurethan those of standard gamma tools, which can exhibitpronounced smoothing effects due to their bigger detec-tor size and lower sampling rate
The Multi-Sensor Gamma Ray Tool (MGT) is a completenatural gamma spectrometry system consisting of four gammaspectrometry sensors and a variety of electronics for pulseprocessing and analysis. Each sensor module includes an NaIdetector with an internal calibration source, programmablepower supply, digital pulse analyzer, and pulse heightstabilization circuitry. Individual calibration results for eachsensor are stored in microcontroller memory; thus, themodules are interchangeable and independently replaceable.Spectral data are collected from each of the four individualgamma ray modules, as well as from downhole accelerometerand temperature sensors, and transmitted uphole to the datareceiver in a surface panel. The MGT increases the verticalresolution of natural gamma ray log data by a factor of 3-4over conventional logging tools, allowing for detailedcharacterization of thin bed layering and sedimentary cycleswhen their gamma ray response is sufficiently large.
♦ Clay typing♦ Mineralogy♦ Ash layer detection
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MGT - HNGS ComparisonHole 1194b
MGTNGT
DEPTH, m
MGT Telemetry
MGT Measurement
Four detectors
spaced at 0.6m
Telemetry section
for data transmission
and to switch from
stand-alone to
combination mode
28.1 meters
33.7 meters
Zero
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