Acoustic reflection logging for open and cased holes. (14th November 2014)

• Record Type: Journal Article
• Authors: Markov, M.; Markova, I.; Jarillo, G. Ronquillo
• Is Part Of: Geophysical prospecting. Volume 63:Number 2(2015:Mar.)
• Page Start: 442
• Page End: 450
• Publication Date: 2014-11-14
• Subjects: Prospecting -- Geophysical methods -- Periodicals; 622.15
• DOI: 10.1111/1365-2478.12197
• Languages: English
• ISSNs: 0016-8025

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <p>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 <italic>Z</italic> = <italic>V_p ρ_s</italic> for fixed parameters of the borehole fluid, where <italic>V_p</italic> is the compressional wave velocity in the rock, and <italic>ρ_s</italic> 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.</p> </abstract>