Abstract of the paper ``Inverting ultrasonic data on solid/fluid mixtures for Biot-Gassmann parameters''
with David E. Lumley
Although the Biot-Gassmann equations are known to predict
acoustic data for water-saturated glass bead packings very well, these
equations often seem to give anomalous results for naturally occurring rocks.
The theory shows that, as the compressibility of the pore fluid increases,
the inverse of the coefficients C and M in Biot's equations should
increase linearly, and the theory also gives definite predictions about the
values of the slope and intercept of the resulting lines. Although the
anticipated linear behavior is observed in real data, the values of the slopes
are smaller than expected for some rocks. Therefore, the process of inverting
this data for the desired coefficients must incorporate other physical
constraints and then produces, not a single value but rather, a range of
possible values for each coefficient.
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