Abstract The infl uence of an acoustic logging tool on borehole guided wave propagation should be considered in the processing and inversion of the guided waves for formation acoustic property estimation. This study introduces an equivalent-tool theory that models the tool response using an elastic rod with an effective modulus and applies the theory to multipole acoustic logging for both wireline and logging while drilling (LWD) conditions.The theory can be derived by matching the tool’s acoustic impedance/conductance to that of the multipole acoustic wavefi eld around the tool, assuming that tool radius is small compared to wavelength. We have validated the effectiveness and accuracy of the theory using numerical modeling and its practicality using fi eld data. In fi eld data applications, one can calibrate the tool parameters by fi tting the theoretical dispersion curve to field data without having to consider the actual tool’s structure and composition. We use a dispersion correction example to demonstrate an appl ication of the simple theory to fi eld data processing and the validity of the processing result.
This work is supported by the Fundamental Research Funds for the Central Universities and the National Hi-tech Research and Development Program of China (863 Program) (Grant No. 2007AA06Z232 ).
About author: Su Yuan-Da graduated from China University of Petroleum (East China) with a Master of Science degree in geo-resources exploration and information Technology in 2004. He has been conducting teaching and research in acoustic logging theory and applications. He is a member of Acoustic Society of China.
Cite this article:
SU Yuan-Da,TANG Xiao-Ming,HEI Chuang et al. An equivalent-tool theory for acoustic logging and applications[J]. APPLIED GEOPHYSICS, 2011, 8(1): 69-78.
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