Method and system for eliminating direct wave interference in acoustic logging, and acoustic logging instrument

Abstract

The invention relates to a method and a system for eliminating direct wave interference in acoustic logging, and an acoustic logging instrument. A transmitting transducer of the acoustic logging instrument transmits logging acoustic waves to two or more receiving transducers; the receiving transducers receive the logging acoustic waves; as for each receiving transducer, the time and slowness related coefficient of the logging acoustic waves is solved out by virtue of scanning in a time domain and a slowness domain, so that a time and slowness related coefficient spectrum is formed; the time and slowness related coefficient spectrum is researched; by virtue of researching a peak value, the slowness of each mode wave of a stratum is determined; the time that each mode wave arrives at the receiving transducers is determined according to the slowness, so that logging analysis data can be provided, wherein the consistency of direct waves received by each receiving transducer is damaged, and the correlation coefficient of the direct waves is reduced, so that the reality and accuracy of useful logging data are realized.

Description

technical field [0001] The present invention relates to a method and system for eliminating direct wave interference in sonic logging performed with a sonic logging tool in which logging is transmitted from a transmitting transducer of the sonic logging tool to two or more receiving transducers Acoustic wave, collecting the well logging sound wave through the receiving transducer, for each receiving transducer, the time slowness correlation coefficient of the well logging sound wave is calculated by scanning in the time domain and the slowness domain, thus The time-slowness correlation coefficient spectrum is formed, the time-slowness correlation coefficient spectrum is searched, the slowness of each mode wave in the formation is determined through peak search, and the oil reservoir and geological characteristics are determined according to the slowness. In addition, the present invention also relates to a corresponding sonic logging tool applied to the method and system. Ba...

AI Technical Summary

Problems solved by technology

The disadvantage is that once the stratum changes drastically, the amplitude of the first wave will fluctuate violently due to the great difference in the attenuation effect of the stratum with different properties on the amplitude of the sound wave, and for the softer stratum, the noise and the amplitude of the first wave are equivalent, and the first wave is more difficult to find. The performance is that the final output logging curve will jump violently, resulting in inaccurate measurement

When the correlation of the formation is weaker than that of the direct wave, it will cause misjudgment

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