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Acoustic reflection logging for open and cased holes
Author(s) -
Markov M.,
Markova I.,
Jarillo G. Ronquillo
Publication year - 2015
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/1365-2478.12197
Subject(s) - borehole , multipole expansion , geology , sonic logging , acoustics , dipole , magnetic monopole , waveform , acoustic impedance , reflection (computer programming) , acoustic wave , reverberation , quadrupole , well logging , physics , geophysics , ultrasonic sensor , atomic physics , geotechnical engineering , quantum mechanics , voltage , computer science , programming language
In the present work, the waveforms of reflected wave sonic log for open and cased boreholes are calculated. Calculations are performed for a borehole containing an acoustic multipole source (monopole, dipole, or quadrupole). A reflected wave is more efficiently excited at resonant frequencies. These frequencies for all source types are close to the frequencies of oscillations of a fluid column located in an absolutely rigid hollow cylinder. It is shown that the acoustic reverberation is controlled by the acoustic impedance of the rock Z = V p ρ s for fixed parameters of the borehole fluid, where V p is the compressional wave velocity in the rock, and ρ s is the rock density. This result is correct for all types of acoustic sources (monopole, dipole, or quadrupole). Methods of the waveform processing for determining parameters characterizing the reflected wave are discussed.