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Radioactivity logging memory tool APRK-2N


The tool has the following modifications by max operating temperature Tmax and upper value of borehole hydrostatic pressure Pmax:
  T max =90 °C, Pmax= 80 MPa;
  T max =120 °C, Pmax= 80 MPa.
Designed to measure water-filled porosity (volumetric moisture content) of formations by neutron-neutron thermal logging (NNLth) and exposure rate (ER) of natural gamma radiation (gamma-ray, GR).

Used for logging of wells drilled with diameter from 120 to 350 mm, wells that have horizontal or nearly horizontal final section filled with any mud.

 well section lithological identification;
 reservoir properties and rocks mineral composition identification;
 gas-bearing formations identification, gas-liquid contact identification.

The measuring equipment of compensated neutron-neutron logging, three-sonde – 3NNKt-24/43/59 (chamber for fast neutron encapsulated source (Pu+Be, with output of 5×106 up to 107 n/sec) . GR measuring equipment consists of two independent detectors (NaJ(Tl) or CsJ(Na) scintillation).


 Measured parameters Range Error
ER of natural gamma radiation 0÷250 mR/h ±15 %
Uranium equivalent mass fraction 0÷200×10-4 % ±(5+140/Ue )%
Water-filled porosity by NNLth 1÷40 % 4.2+2.3(40/phi-1)

 General specifications
Tool length, mm 4715 not more than
Tool diameter, mm 73 not more than
Tool weight, kg 57 not more than
Power supply, self-contained, V 12  
Max operating temperature,0C from -10 to +120 not more than
Max operating pressure, MPa 80 not more than
Borehole diameter, mm 120÷350  
Logging speed, m/ hr 800  
Operating time in memory mode,  hours in record mode 10 not less than
Records frequency, pollings per sec. 2 (10 pollings per 
1 m)
Location in light alloy drilling pipe or container