 |
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 |
|
|