Systems and methods for using stoneley waves for bottom-hole proximity detection

A method comprising:

• emitting, from a downhole tool, a plurality of Stoneley waves into a borehole in a pulse sequence;
• detecting, via a plurality of sensors, the plurality of Stoneley waves traveling in the borehole;
• and
• calculating, via the processor, a distance from the downhole tool to a bottom of the borehole based at least in part on the speed of the plurality of Stoneley waves in the borehole and a time between detections of the plurality of Stoneley waves.

Machine-executable instructions stored on a tangible, non-transitory machine readable storage medium, which, when executed by a machine, causes the machine to perform a method, the method comprising:

• controlling an emission of one or more Stoneley waves at a plurality of locations in a borehole;
• processing signals received from one or more Stoneley wave sensors, wherein the signals are representative of the one or more Stoneley waves sensed within the borehole;
• calculating a direction of travel of the one or more Stoneley waves;
• calculating a roundtrip time of the one or more Stoneley waves propagating down the borehole and reflecting back to the one or more Stoneley wave sensors at a bottom of the borehole based at least in part on the direction of travel of the one or more Stoneley waves;
• and
• calculating a distance from a bottom-hole assembly to the bottom of the borehole based at least in part on the roundtrip time of the one or more Stoneley waves.