Acoustic Imaging Away From the Borehole Using a Low-Frequency Quadrupole Excitation

摘要

Acoustic measurements made in a borehole using a multipole source are used for imaging a near-borehole geological formation structure and determination of its orientation. The signal to noise ratio (as defined by the ratio of the signal radiated into the formation to the axially propagating signal) depends upon the type of source (force or volume) and its position in the borehole (on the tool, in the fluid or on the borehole wall).