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Compensated acoustic logging tool 4AK


The tool has the following modifications by max operating temperature T max and upper value of borehole hydrostatic pressure Pmax :
 by temperature: 120, 150, 175, 200 °С,
 by pressure: 80, 100, 120, 140 МPа.
Designed to measure propagation parameters of head waves and wave along the casing string.

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

 determination of porosity and rocks elasticity modulus in open holes;
 casing string cementing evaluation.

The measuring sonde consists of two transmitters T1, T2 and two receivers R1, R2 of elastic oscillations divided by acoustic insulators and placed at the opposite ends of the sonde. The couples of transmitters and receivers form two spacings with reversed transmitter-receiver configurations – compensated sonde. Transmitters are cylindrical and magnetostrictive with base frequency of 20 kHz. Sondes formulas are R20.4R11. 0T10.4T2

 Measured parameters (for LogPWin software) Range Error
Open hole measurements:
compressional wave slowness
shear wave slowness
P-wave attenuation factor
Cased hole measurements:
wave along the casing string attenuation factor

100÷500 µsec/m
100÷500 µsec/m
0÷20 dB/m

0÷20 dB/m
20÷30 dB/m

±15 µsec/m
±15 µsec/m
±3 dB/m

±3 dB/m
±6 dB/m

 General specifications
Tool length, mm 4550 not more than
Tool diameter, mm 76 not more than
Max diameter with centralizers, mm 90 not more than
Tool weight, kg 80 not more than
Power supply:
supply voltage, V
supply frequency, Hz


Borehole diameter, mm 110÷350  
Casing string diameter, mm 127÷245  
Logging speed, m/hr 800  
Combinability feed-through  
Location in the borehole must be centralized