SONIC WELL LOGGING TOOL FOR RADIALLY SCANNING CEMENTING CONDITIONS IN CASED WELLS

摘要

A sonic well logging tool radially determinescircumferential placement of cement longitudinally alongexterior surfaces of a well casing. The sonic well loggingtool includes a frequency shifting modulator for shiftingthe frequency of high frequency electrical signals toprovide analog data signals having substantially lowerfrequencies. The analog data signals have waveform shapeswhich directly correspond to time stretching the shapes ofwaveforms for the high frequency electrical signalsrepresenting high frequency sonic signals. The highfrequency electrical signals are frequency shifted tosubstantially lower frequencies which can be transmitteduphole over a wireline. The sonic well logging toolfurther includes high frequency sonic transducers which donot extend in a particular direction for substantially morethan one quarter of a sonic waveform length of the highfrequency sonic signals travelling in the particulardirection within a sector of casing.