GAMMA RESISTIVITY SELF POTENTIAL NEUTRON

SPECIFICATIONS

System Requirement Logger 20 / ALT logger
Diameter 40 mm
Length 2.90 m
Weight 15 kg
Max. pressure 200 bars =2900psi
Max. temp. 70º C
Power supply 35 - 40 V
Detectors GR - NaI(Tl) Neutron He3
Source (Neutron) Am 241 Be 1 or 3 Currie
Logging speeds 6 m/min
Hole diameter min. 60 mm

LOG PARAMETERS

Natural Gamma Ray (GR)
Neutron (Neut) or (NPOR).
Self Potential (SP)
Single Point Resistance (SPR)
16 inch Normal (16NR)

APPLICATIONS

Gamma Ray logs measure the naturally occurring gamma emissions from the formation surrounding the borehole. These emissions are electromagnetic
radiations that are released by a nucleus of an unstable element, decaying to a more stable state. In nature, the most significant of these elements occurring in abundance is potassium 40 (K40),
uranium 238 (U238), uranium 235 (U235) and thorium 232 (TH232). The most plentiful of these elements is potassium 40.

As the unstable element decays, issuing electromagnetic radiation, the gamma ray probe detects the events by recording the number of particles or photon emissions. This detection is accomplished by use of a sodium iodide crystal optically coupled to a photo-multiplier. As the incident photon enters the crystal a release of energy takes place in the form of illumination that is detected by the photo-multiplier. A corresponding voltage is delivered to the surface where it is counted and averaged over a specific time period. Since radiation is of a statistical nature it is necessary to average the measurement of radiation over a selectable time period in order to derive a representative sample of the amount of
radiation being emitted.

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