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Method and system for generating a beam of acoustic energy from a borehole, and applications thereof

United States Patent

February 14, 2012
View the Complete Patent at the US Patent & Trademark Office
Los Alamos National Laboratory - Visit the Technology Transfer Division Website
A compact array of transducers is employed as a downhole instrument for acoustic investigation of the surrounding rock formation. The array is operable to generate simultaneously a first acoustic beam signal at a first frequency and a second acoustic beam signal at a second frequency different than the first frequency. These two signals can be oriented through an azimuthal rotation of the array and an inclination rotation using control of the relative phases of the signals from the transmitter elements or electromechanical linkage. Due to the non-linearity of the formation, the first and the second acoustic beam signal mix into the rock formation where they combine into a collimated third signal that propagates in the formation along the same direction than the first and second signals and has a frequency equal to the difference of the first and the second acoustic signals. The third signal is received either within the same borehole, after reflection, or another borehole, after transmission, and analyzed to determine information about rock formation. Recording of the third signal generated along several azimuthal and inclination directions also provides 3D images of the formation, information about 3D distribution of rock formation and fluid properties and an indication of the dynamic acoustic non-linearity of the formation.
Johnson; Paul A. (Santa Fe, NM), Ten Cate; James A. (Los Alamos, NM), Guyer; Robert (Reno, NV), Le Bas; Pierre-Yves (Los Alamos, NM), Vu; Cung (Houston, TX), Nihei; Kurt (Oakland, CA), Schmitt; Denis P. (Katy, TX), Skelt; Christopher (Houston, TX)
Chevron U.S.A. Inc. (San Ramon, CA)
12/ 137,980
June 12, 2008
GOVERNMENT RIGHTS This invention was made with Government support under Cooperative Research and Development Agreement (CRADA) Contract Number DE-AC52-06NA25396 awarded by the United States Department of Energy. The Government may have certain rights in this invention.