Method for driving a bender-type transmitter of a borehole logging tool to sequentially produce acoustic compressional and tube waves

摘要

An acoustic well logging system employs a sine wave tone burst generator which drives a bender-type transmitter in a borehole logging tool to sequentially produce acoustic compressional and tube waves. A sine wave tone burst is selectively swept or fixed in frequency between 10 kHz and 1.5 kHz to generate a constant frequency compressional wave and below 1.5 kHz to generate a constant frequency tube wave. The constant frequency of the compressional wave along a particular subsurface formation interval is characteristic of the rock material of such subsurface formation interval.