Chevron U.s.a. Inc.

Triad National Security, LLC

Peter Roberts

Harvey Edwin Goodman

Marcel Remillieux

Paul Allan Johnson

Pierre-Yves Le Bas

Robert A Guyer

Timothy James Ulrich, Ii

Apparatus and methods for measurement of pore pressure in rock formations through an open, or cemented and/or cased, borehole are described. Such measurements are achieved using the Dynamic Acoustic Elasticity (DAE) method for characterizing nonlinear parameters by perturbing a selected rock formation volume with a High Amplitude, Low Frequency (HALF) acoustic strain wave, and probing this volume using a Low Amplitude, High Frequency (LAHF) acoustic wave. Time reversal techniques may be employed for focusing acoustic energy Into the formation in the vicinity of the pipe or open hole.

Downhole nonlinear acoustics measurements in rock formations using dynamic acoustic elasticity and time reversal

An apparatus () and method for performing nonlinear elasticity measurements using the dynamic acousto-elasticity technique (DAET) at simulated subsurface conditions in the laboratory, are described. The current state-of-the-art for measuring nonlinear elasticity parameters using DAET is limited to ambient pressure conditions on the bench-top. The present invention permits nonlinear parameter measurements at controlled sample internal fluid pore pressures () and external confining stress (), () conditions.

Apparatus and method for dynamic acousto-elasticity technique measurements at simulated subsurface pressures

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Los Alamos, NM, United States of America

Peter Roberts