Borehole Stoneley Wave Propagation Across Permeable Structures: Comparison Between Theory And Experiment
Name
1992.4 Zhu et al.pdf
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558.88 KB
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Checksum (MD5)
2097d625c9012904cea09a5bf211190f
Author(s)
Zhu, Zhenya
Tang, Xiaoming
Cheng, C. H.
Toksoz, M. N.
Date Issued
1992
Publisher
Massachusetts Institute of Technology. Earth Resources Laboratory
Series/Report no.
Earth Resources Laboratory Industry Consortia Annual Report;1992-04
Abstract
The attenuation of borehole Stoneley waves across a permeable structure (e.g., fractures
or fracture zone) is correlated with the permeability of the structure. Using a
simplified Biot theory, the structure can be modelled as a permeable porous layer intersecting the borehole. In order to study the effect of such a structure on Stoneley waves and to evaluate the theoretical model, we performed laboratory experiments using ultrasonic borehole models. The porous layer model is made of fine-grained sands with
high permeability and porosity. The experiments are carried out with three saturant
fluids: water, alcohol, and glycerol. The iso-offset Stoneley waveforms are recorded by
moving the source and receiver across the porous layer. In this way, robust estimates
of Stoneley wave transmission coefficients are obtained. The experimental transmission
coefficients are compared with the theoretical coefficients calculated using the borehole
and permeable zone parameters. There is good agreement between theoretical results
and experimental results. For low viscosity fluid water and ethyl alcohol, the agreement
is very good. For high viscosity fluid, glycerol, the agreement is fair with the
experimental Stoneley attenuation higher than the theoretical value.
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