Determining locations of acoustic sources around a borehole

A system for determining a location of an acoustic source outside of a borehole, the system comprising:

• a tool having acoustic sensors spaced along the tool;
• a processor electronically coupled to the tool to receive acoustic data signals from respective ones of the acoustic sensors;
• and
• a computer-readable storage device storing instructions that, when executed by the processor, cause the processor to perform operations comprising:
• receiving the acoustic data signals from the respective ones of the acoustic sensors;
• calculating, from the acoustic data signals, stacked energies for different radial distances from the borehole, wherein the stacked energy for each different radial distance from the borehole is computed by offsetting the acoustic data signals in time in accordance with a borehole model specifying acoustic delay to the respective acoustic sensor as a function of the radial distance from the borehole and an offset in the displacement along the borehole to the respective acoustic sensor, and summing the offset acoustic data signals to produce a stacked signal, and evaluating energy of the stacked signal over a time window;
• and
• translating at least one of the stacked energies to an indication of a radial distance of the acoustic source from the borehole.

A computer-readable storage device storing instructions which, when executed by a computing device, cause the computing device to determine a location of an acoustic source outside of a borehole by perform operations comprising:

• receiving acoustic data signals from respective acoustic sensors spaced along a tool lowered within a borehole;
• calculating, from the acoustic data signals, stacked energies for different radial distances from the borehole, wherein the stacked energy for each different radial distance from the borehole is computed by offsetting the acoustic data signals in time in accordance with a borehole model specifying acoustic delay to the respective acoustic sensor as a function of the radial distance from the borehole and an offset in the displacement along the borehole to the respective acoustic sensor, and summing the offset acoustic data signals to produce a stacked signal, and evaluating energy of the stacked signal over a time window;
• and
• translating at least one of the stacked energies to a radial distance of the acoustic source from the borehole.