Computation of Linear Elastic Properties from Microtomographic Images: Methodology and Match to Theory and Experiment.
Computation of Linear Elastic Properties from
Microtomographic Images: Methodology and Match to Theory
Arns, C. H.; Knackstedt, M. A.; Pinczewski, W. V;
Garboczi, E. J.
Journal of Geophysics, Vol. 67, No. 5, 1396-1405,
elastic property; finite elements; porosity; saturation;
microtomography; petrophysics; rock morphology
Elastic property-porosity relationships are derived
directly from microtomographic images. This is
illustrated for a suite of 4 samples of Fontainebleau
sandstone with porosities ranging from 7.5% to 22%. A
finite element method is used to derive the elastic
properties of digitized images. By estimating and
minimizing several sources of numerical error very
accurate predictions of properties are derived in
excellent agreement with experimental measurements over
a wide range of the porosity. We consider the elastic
properties of the digitized images under dry, water- and
oil-saturated conditions. The observed change in the
elastic properties due to fluid substitution is in
excellent agreement with the exact Gassmann equations.
This shows both the accuracy and the feasibility of
combining microtomographic images with elastic
calculations to accurately predict petrophysical
properties of individual rock morphologies. We compare
the numerical predictions to various empirical,
effective medium and rigorous approximations used to
relate the elastic properties of rocks to porosity under
different saturation conditions.