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The tool generates a continuous oriented 360° image of
the borehole wall unwrapped using an optical imaging system (downhole CCD
camera which views a reflection of the borehole wall in a prism mirror). The
tool includes a full orientation device consisting of a precision 3 axis
magnetometer and 2 accelerometers thus allowing for both accurate borehole
deviation data to be obtained during the same logging run, and for accurate
and precise orientation of the image.
The optical televiewer is fully downhole digital and can
be run on any standard winches (mono, 4 conductors, 7 conductors). It is
directly compatible with the ALT acquisition system using acquisition and
processing software (ALTlogger and WellCAD). Resolution is user definable
(up to 0.5 mm Vertical resolution and 720 pixels Azimuthal resolution).
Applications :
The purpose of the optical tool is to provide detailed, oriented,
structural information when the accoustic cannot operated (air or clean
water filled boreholes)
fracture detection and evaluation
detection of thin beds and bedding dip
lithological characterization
casing inspection
high resolution caliper measurements
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