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Radioactive logging combined tool ARK


The tool has the following modifications by max operating temperature T max and upper value of borehole hydrostatic pressure Pmax:
  by temperature: 120°С,
 by pressure: 80 МPа.
Designed to measure exposure rate (ER) of natural gamma radiation and water-filled porosity by compensated thermal neutron-neutron logging - 3NNLth.

Used for logging of open and cased oil and gas holes filled with any mud; operates with a three-conductor carrying logging cable up to 7000m long and log recorders that provide for command transfer and data receipt in “Manchester-2” code.

 well sections and lithological changes correlation;
 detailed lithological identification;
 gas-bearing formations identification, gas-liquid and oil-water contact identification;
 gas saturation coefficient determination.

The measuring equipment of compensated neutron-neutron logging contains a chamber for fast neutron encapsulated source (Pu+Be, with output of 5×106 up to 107 n/sec) and three helium thermal neutron detectors. GR measuring equipment contains two scintillation gamma quantum detectors.

 Measured parameters Range Error
ER of natural gamma radiation 0÷250 μR/hr ±15 %
Water-filled porosity by 3NNLth 1÷40 % 4.2+2.3(40/phi-1)%

 General specifications
Tool length, mm 3400 not more than
Tool diameter, mm 76 not more than
Tool weight, kg 50 not more than
Power supply:
supply voltage, V
supply frequency, Hz


Borehole diameter, mm 110÷350  
Logging speed:
in terrigenous section, m/hr
in carbonate section, m/hr

Combinability feed-through  
Location in the borehole free