  A quantitative comparison between the experimental microstructure of a
sedimentary rock and three theoretical models for the same rock is presented.
The microstructure of the rock sample (Fontainebleau sandstone) was obtained by
microtomography. Two of the models are stochastic models based on correlation
function reconstruction, and one model is based on sedimentation, compaction
and diagenesis combined with input from petrographic analysis. The porosity of
all models closely match that of the experimental sample and two models have
also the same two point correlation function as the experimental sample. We
compute quantitative differences and similarities between the various
microstructures by a method based on local porosity theory. Differences are
found in the degree of anisotropy, and in fluctuations of porosity and
connectivity. The stochastic models differ strongly from the real sandstone in
their connectivity properties, and hence need further refinement when used to
model transport.
