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Waveform acoustic logging tool АVАК-11

АВАК-11

The tool has the following modifications by max operating temperature T max and upper value of borehole hydrostatic pressure Pmax
 by temperature: 120, 150°С,
 by pressure: 80, 100, 120 МPа.
Designed to measure propagation parameters of compressional, shear and Stonely waves including measuring in low-velocity sections and through the casing string.

Used for open and cased holes filled with water- or oil-base mud; operates with a three-conductor logging cable up to 7000 meters long.

Applications:
 well section lithological identification;
 determination of rocks porosity factor and type;
 permeable formations identification;
 estimation of rocks elasticity modulus;
 evaluation of near-borehole zone acoustic anisotropy and filtration properties. 

The measuring sonde includes: transmitter unit and two receiver units divided by acoustic insulators. The transmitter unit contains three monopole transmitters IM1, IM2, IM3 and two dipole transmitters in one cross-section ID1, ID2 (cross-dipole). IM1 transmitter is cylindrical and magnetostrictive with basic frequency of 20 kHz;   IM2  transmitter is piston and magnetostrictive with basic frequency of 8 kHz and radiation pattern solid angle at the level of 0.5¸60°;   IM3 transmitter is piston and magnetostrictive with basic frequency of 2.5 kHz. Transmitters ID1, ID2 are piezoelectric ceramic with basic frequency of 4 kHz. The receiver units are identical and each of them contains one monopole receiver PM1 and PM2 and two dipole receivers PD1 and PD2 (cross-dipoles). Sondes formulas:  
for monopole transmitter with basic frequency of 20 kHz: PМ20.5PМ11.5IМ1;
for monopole transmitter with basic frequency of 8 kHz: PМ20.5PМ12.0IМ2;
for Stonely wave excitation: PМ20.5PМ12.0IМ3;
for dipole transmitter: PD20.5PD11.7ID.

 Measured parameters Range Error
Slowness, μsec/m:
compressional wave
shear wave from monopole sondes
shear wave from dipole sondes
Stoneley wave

120÷600
250÷600
250÷800
600÷900

from +5 to -5
from +10 to -10
from +10 to -10
from +10 to -10

Attenuation coefficient (amplitude ratio), dB/m:
compressional wave at 20 and 8 kHz frequencies
shear wave from monopole sondes
shear wave from dipole sondes
Stonely wave


0÷20
0÷20
0÷20
0÷20

from +3 to -3
from +3 to -3
from +3 to -3
from +3 to -3

General specifications
Tool length, mm 6000 not more
Tool diameter, mm 90 not more
Weight, kg 160 not more
Power supply:
supply voltage, V
frequency, Hz

220
50

10%
1%
Borehole diameter, mm 120÷290  
Logging speed, m/hr 400
at polling interval of 0.2m
 
Combinability feed-through  
Location in the borehole must be centralized  

Прибор волнового акустического каротажа АВАК-11