FremgangsmÕte og apparat for akustisk skjµrb°lge-logging

摘要

A borehole logging tool (13) having a dipole acoustic energy source (16) and a plurality of spaced-apart dipole acoustic energy receivers (17) is lowered into a deviated borehole (14) penetrating a subsurface formation. The dipole source (16) and receivers (17) are positioned eccentrically with respect to the borehole axis and are focused in the same direction perpendicular to the axis of the borehole tool as well as perpendicular to the direction of such eccentricity so that received tube wave amplitudes are minimized with respect to received shear wave amplitudes.