The accelerometer/temperature tool is used to make environmental corrections to logs made by other sensors.
Acceleration data is passed through special processing software to compute the instantaneous deviation in depth from the indicated value provided by the measure-wheel, caused by stick-slip or yo-yo motion of a tool string.
Temperature (internal) is used to correct for thermal expansion of a long tool-string that introduces errors into the depth offsets.
These corrections must be combined with accurate calibrated values of the measure-points for each tool in the string, for maximum accuracy.
The tool was specifically designed for use in Formation-Compaction monitoring. It is combined in a stack with multiple NGT-B Gamma-ray and ICL-A collar locator tools, and used to determine depths of collars and radio-active tags to an accuracy of +/- 0.5 inches at depths to 15,000 feet.