The Hole Mole™ is the tool that started it all!  Designed and manufactured by Sonasearch for surveying saturated-brine filled storage caverns, the Hole Mole was the first computer-controlled, long-line survey tool certified for use in the Strategic Petroleum Reserve by Sandia National Labs.

The Hole Mole was a revolutionary concept that provided an accurate picture and volumetric survey of fluid-filled underground caverns.

The system consisted of a SONASEARCH Hole Mole downhole probe communicating with
a modified NEC APC personal computer via a proprietary communications interface over up to 25,000 feet of Rochester H-314 single-conductor wireline.

A field engineer commanded the downhole electronics to sweep the structure.  Ensonified echo returns were received, digitized and transmitted to the surface for display on the high-resolution color video monitor.  Rotation speed and pulse rate were under software control as a function of selected range and corrected for speed of sound.  The data stored to disk included date, depth, distance in feet of the radii, angle of tilt in degrees and angle of
rotation in degrees.  On completion of the survey, the survey data was available to the field engineer for post processing and reporting.