 |
ACOUSTIC TELEVIEWER
Tool design philosophy & applications
Acoustic Borehole scanner tools generates
an image of the borehole wall by transmitting ultrasound pulses
from a rotating sensor and recording the amplitude and travel
time of the signals reflected at the interface between mud and
formation (borehole wall).
Most common applications are
•
Fracture detection and evaluation
•
Detection of thin beds
•
Determination of bedding dip
•
Lithological interpretation
•
Breakout analysis
•
Monitoring of earth stress field
•
Casing inspection
•
High resolution caliper
The latest generation of ALT acoustic televiewer
is a multi-echo system. This is achieved by digital recording
of the reflected wave train. On line analysis of the acoustic
data is made by a DSP (Digital Signal Processor). Sophisticated
algorithms allow the system to detect the reflection from the
acoustic window and to separate/classify all subsequent echoes.
Minimum input of the operator is needed to enable:
•
Automatic optimization of measurement window under all borehole
conditions
•
Automatic adaptation to variable borehole conditions
•
Improvement of dynamic range of signal detection
•
Very high travel time resolution
•
Implementation of different operating mode
Main features
•
Direct linear 14bit, 10mhz A/D conversion (automatic gain settings)
•
Dynamic range of amplitude measurement is 84 db
•
Calliper resolution is better than 0,1mm
•
Orientation sensor which does not require field calibration
•
Increased telemetry bandwidth (data transmission rate up to 500kbits
depending on wireline), 166kbps typical on 300m four-conductors.
•
Full wave form recording and real time display for quality control
•
Multiecho mode to realize acoustic measurements through plastic
pipes (require the plastic pipe to be centralized inside the borehole)
•
Pipe-inspection mode to detect inner corrosion, outer corrosion,
and wall thickness
•
Automatic measurement window definition to gain optimum performance
and variable borehole conditions
 top
ABI40-2G tool specifications PDF
|
diameter
length
weight
Max temp
Max pressure
Borehole diameter
|
40mm
1.61m
6.7 kgs
70°c
200 bar
2” to 21” depending on mud conditions |
Processing acoustic data
top
ABI85 tool specifications PDF
The ABI85 is a new generation of high temperature and high-pressure
acoustic imaging tool based on the well-known ABI40 televiewer
technology.
Dewar technology is applied to shield the electronics.
Maximum operating time is 10 hours at 275°C ambient temperature.
 
|
diameter
length
weight
Max temp
Max pressure
Borehole diameter
|
85mm (3” 3/8)
5.2m with ‘inline’ centralisers, 3.7m without
‘inline’ centralisers
150kgs
275°c for 10 hours
800 bar (12000 PSI)
4” to 25” depending on mud conditions |
Processing acoustic data
top
|
