Patent ID: 7839718
Filing Date: 2010-11-23
Classification: G01V

Abstract:
1. A method of generating a beam of acoustic energy in a borehole, the method comprising: generating a first acoustic wave at a first frequency; generating a second acoustic wave at a second frequency different than the first frequency, wherein the first acoustic wave and second acoustic wave are generated by at least one transducer arranged on a tool located within the borehole; transmitting the first and the second acoustic waves into an acoustically non-linear medium, wherein the composition of the non-linear medium produces a collimated beam by a non-linear mixing of the first and second acoustic waves, wherein the collimated beam propagates through the non-linear medium in a same direction as an initial direction of the first and second acoustic waves and has a frequency equal to a difference of the frequencies of the first and the second acoustic waves; and directing the collimated beam by a steering device in at least one direction with respect to the tool away from the borehole into the material around the borehole, wherein the collimated beam has a frequency of at least 20 kHz.